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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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Non-modulating condensing boilers?
Choosing a boiler again... but can anyone suggest any non-modulating
condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) .. |
#2
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This would be for a Thermal Store system, for which flame modulation is
(in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. There's no problem in using a modulating burner for this. Indeed, it can actually be beneficial, as when the store gets nearly full, a non-modulating one can start cycling on the boiler stat when the store stat is not yet satisfied, particularly if the pump speed is fairly slow. Christian. |
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In article , Egremont
writes Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. One of the benefits of a modulating one would be that it would modulate to keep the boiler in condensing mode. That would be useful towards the end of a cycle when the temperature of the store is reaching it's demand level and the return temperature would rise, given continued max output. I see this with my own (large) hot water cyl when it starts out on full whack, then backs off a bit towards the end, usually a 20min cycle with the last 5mins backed off to half power. My Keston Celsius 25 has been reported here once as not liking driving thermal stores, don't know why but I recall it from way back. Sorry for not answering the question :-). -- fred |
#4
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"Egremont" wrote in message ... Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) The Baxi has a jumper on the pcb, which eliminates the modulating. Maxie may know of some pcbs (boilers) with the same function. |
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On Wed, 20 Jul 2005 13:01:45 GMT, "Egremont"
wrote: Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) You would be better off with a modulating one driving the radiators directly and the cylinder of the thermal store directly, with the thermal store used only for hot water. In this way, when the heating requirement for the space heating is fairly low, as it is for a large proportion of the year in the UK, the boiler will run at lower temperatures and far more efficiently than it will if you always drive a thermal store with it. If you drive a thermal store with a modulating boiler, it will wind up to full power for much of the recharging cycle anyway and you will eliminate/reduce cycling. Lack of cycling is one mechanism for efficiency. Running at lower temperatures where efficiency is better anyway and heat recovery from latent heat can happen is the other. Condensing boilers of a few years ago had an efficiency advantage over non condensing because normally they had larger and more efficient heat exchangers. More recently, non-condensing caught up. Operationally, you want the thermal store to recover quickly. You won't be running the boiler at low temperatures during that time anyway, so the only efficiency gain comes from not having cycling. You don't need a non modulating boiler to achieve that. For space heating, you are better off taking advantage of the fact that by directly driving the radiators, the boiler can modulate down and run cooler while still not cycling. If you put a thermal store in the middle, then you prevent that from happening. The only exception to this is if you were introducing a "free" source of energy such as solar. In that case a thermal store is useful to combine sources. Other than that, it is a good way to heat the water but not a good way to maximise efficiency from a condensing boiler. -- ..andy To email, substitute .nospam with .gl |
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"Andy Hall" wrote in message ... On Wed, 20 Jul 2005 13:01:45 GMT, "Egremont" wrote: Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) You would be better off with a modulating one driving the radiators directly He wouldn't at all. and the cylinder of the thermal store directly, with the thermal store used only for hot water. He has the heating already off the store in two zones. snip |
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On Wed, 20 Jul 2005 16:18:24 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message .. . On Wed, 20 Jul 2005 13:01:45 GMT, "Egremont" wrote: Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) You would be better off with a modulating one driving the radiators directly He wouldn't at all. and the cylinder of the thermal store directly, with the thermal store used only for hot water. He has the heating already off the store in two zones. snip This does not make optimal use of a condensing boiler, let alone a modulating one. -- ..andy To email, substitute .nospam with .gl |
#8
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"Andy Hall" wrote in message ... On Wed, 20 Jul 2005 16:18:24 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message .. . On Wed, 20 Jul 2005 13:01:45 GMT, "Egremont" wrote: Choosing a boiler again... but can anyone suggest any non-modulating condensing boilers in the 24-28kW range?. The one suggestion I've seen so far is Quantum Heatsave, I'd need too check physical size, cost etc so a choice of more than 1 would be good. This would be for a Thermal Store system, for which flame modulation is (in theory) an unneccessary waste. On the other hand, I'm thinking I might be better off just 'going with the flow' and getting a standard (modulating) boiler regardless of the redundant fucntion. Egremont. PS - there is a background that's been gone into in another thread (which I'm still looking into...) You would be better off with a modulating one driving the radiators directly He wouldn't at all. and the cylinder of the thermal store directly, with the thermal store used only for hot water. He has the heating already off the store in two zones. snip This does not make optimal use of a condensing boiler, let alone a modulating one. It does. Only a cheaper, simpler more reliable boiler need be used. |
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[Had to edit this post, line-breaks may be off...] OK I've read many of your previous discussions in this area and didn't want to take you back over old ground!. I will mention a few things as relates to my installation: 1) The store has two 'stats to combat boiler cycling (you can blame Dr Evil) 2) My pump is indeed a bit slow (10L/min max), so much so that something will probably have to be done. 3) The water sent to the current boiler (from the bottom of the 1300mm store) seems to be surprisingly cool(ish) in relation to the overall temperature of the store, the space-heating take off is high up which probably helps. This should help condenser efficiency though may not be the whole story!. As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. Egremont. |
#10
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"Egremont" wrote in message ... [Had to edit this post, line-breaks may be off...] OK I've read many of your previous discussions in this area and didn't want to take you back over old ground!. I will mention a few things as relates to my installation: 1) The store has two 'stats to combat boiler cycling (you can blame Dr Evil) 2) My pump is indeed a bit slow (10L/min max), so much so that something will probably have to be done. 3) The water sent to the current boiler (from the bottom of the 1300mm store) seems to be surprisingly cool(ish) in relation to the overall temperature of the store, the space-heating take off is high up which probably helps. This should help condenser efficiency though may not be the whole story!. As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. Illegal. Only fitted in exceptional circumstances, which difficult to achieve. Stick to a condensing boiler, as they are cheaper to run. Look at the Baxi, this can be non-modulating. The two stats work with any boiler and will enhance condensing as the when the stat call for hot water the cylinder will be pretty cool promoting efficiency. |
#11
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Keston 25 was once on my short-list, partly due to it's shallow depth (a
particular requirement) but negative comment from various sources on reliability and support, though not universal, has put me off. At this point, Worcester Greenstar R 24i (I think it was!) is one possible alternative on the fully modulating front, but I think selecting a boiler will be easy(er) if I can reasonably forget about non-modulation. Egremont |
#12
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In article , Egremont
writes Keston 25 was once on my short-list, partly due to it's shallow depth (a particular requirement) but negative comment from various sources on reliability and support, though not universal, has put me off. At this point, Worcester Greenstar R 24i (I think it was!) is one possible alternative on the fully modulating front, but I think selecting a boiler will be easy(er) if I can reasonably forget about non-modulation. My choice was limited to only one or two boilers by a requirement for a really long flue and the Keston won on cost of both boiler and the low cost flue (plastic drain pipe) but if that's not important there are many others out there. I've not had any trouble with mine and I was able to talk to directly to one of their technical bods when I needed a hand at commissioning time but as I'm sure you've seen, that's not everyone's experience. Build quality looks good on a chum's recently fitted non-condensing Worcester Bosch but that's as much as I know of them. Good luck. -- fred |
#13
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On Wed, 20 Jul 2005 17:39:51 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message This does not make optimal use of a condensing boiler, let alone a modulating one. It does. Only a cheaper, simpler more reliable boiler need be used. Sorry but no, as has been demonstrated before. -- ..andy To email, substitute .nospam with .gl |
#14
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On Wed, 20 Jul 2005 17:30:53 +0000, Egremont wrote:
[Had to edit this post, line-breaks may be off...] As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. Yes, they are on offer at more than one place around here, one advertises on the side of the building (in bright pink, as they do) COMBI 310+VAT.!!! Can they be fitted? Yes it's physically possible. Is it legal to fit them? no (but for very exceptional exceptions). Will anything come of fitting one? Almost certainly not unless some other work was involved in the same place that brought in some authority. Should you fit one? Depends on how serious you are about energy efficiency, 'saving the planet', fixing to sell or fixing to dwell? etc.etc. -- Ed Sirett - Property maintainer and registered gas fitter. The FAQ for uk.diy is at http://www.diyfaq.org.uk Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html |
#15
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On Wed, 20 Jul 2005 17:30:53 GMT, "Egremont"
wrote: [Had to edit this post, line-breaks may be off...] OK I've read many of your previous discussions in this area and didn't want to take you back over old ground!. I will mention a few things as relates to my installation: 1) The store has two 'stats to combat boiler cycling (you can blame Dr Evil) 2) My pump is indeed a bit slow (10L/min max), so much so that something will probably have to be done. 3) The water sent to the current boiler (from the bottom of the 1300mm store) seems to be surprisingly cool(ish) in relation to the overall temperature of the store, the space-heating take off is high up which probably helps. This should help condenser efficiency though may not be the whole story!. As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. If you are going to hook the boiler up to a thermal store for space heating, it won't make a lot of difference because it will seldom run cool enough to take advantage of low temperature condensing operation. You will get bursts of high power operation as the store is periodically replenished and the return temperature will initially be cool. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. If the condensing boiler drives the radiators directly, the flow temperature can be allowed to fall substantially and the return even more so that the burner will tend to run continuously at low output rather than cycling at a higher temperature range to drive a store. Use of a store makes good sense for DHW purposes if sufficient mains flow is available. For space heating, unless other energy sources are being added in, it defeats the designed in optimisation of the boiler which will then run less efficiently. -- ..andy To email, substitute .nospam with .gl |
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"Ed Sirett" wrote in message news On Wed, 20 Jul 2005 17:30:53 +0000, Egremont wrote: [Had to edit this post, line-breaks may be off...] As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. Yes, they are on offer at more than one place around here, one advertises on the side of the building (in bright pink, as they do) COMBI 310+VAT.!!! Can they be fitted? Yes it's physically possible. Is it legal to fit them? no (but for very exceptional exceptions). Will anything come of fitting one? Almost certainly not unless some other work was involved in the same place that brought in some authority. Should you fit one? Depends on how serious you are about energy efficiency, 'saving the planet', fixing to sell or fixing to dwell? etc.etc. Or saving money on gas bills too. |
#17
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"Andy Hall" wrote in message ... On Wed, 20 Jul 2005 17:30:53 GMT, "Egremont" wrote: [Had to edit this post, line-breaks may be off...] OK I've read many of your previous discussions in this area and didn't want to take you back over old ground!. I will mention a few things as relates to my installation: 1) The store has two 'stats to combat boiler cycling (you can blame Dr Evil) 2) My pump is indeed a bit slow (10L/min max), so much so that something will probably have to be done. 3) The water sent to the current boiler (from the bottom of the 1300mm store) seems to be surprisingly cool(ish) in relation to the overall temperature of the store, the space-heating take off is high up which probably helps. This should help condenser efficiency though may not be the whole story!. As for the boiler... pendulum swinging towards a 'normal' modulating boiler I think. Apart from anything else, Quantum Heatsave seems to be the only known specialist option. BTW can you really still get non-condensers?. If you are going to hook the boiler up to a thermal store for space heating, it won't make a lot of difference It will make quite a difference. because it will seldom run cool enough to take advantage of low temperature condensing operation. He has two stats so the store will enough for the cool mass to be heated all at once with ample coll return water. You will get bursts of high power operation as the store is periodically replenished and the return temperature will initially be cool. For quite a while. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. Only at the end. The operation temp of the store can be lowered to promote cooler operation. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boioer kW has bottomed out. Alos means zone valve for zone, 3-ways, and other complexity. the flow temperature can be allowed to fall substantially and the return even more so that the burner will tend to run continuously at low output rather than cycling at a higher temperature range to drive a store. Will not cycle heating the store as two stats are used. Will cylce directly on the rad circuits. Problems always when fitting therostat rad valves. Use of a store makes good sense for DHW purposes if sufficient mains flow is available. For space heating, unless other energy sources are being added in, it defeats the designed in optimisation of the boiler which will then run less efficiently. Nonsense. |
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"Andy Hall" wrote in message ... On Wed, 20 Jul 2005 17:39:51 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message This does not make optimal use of a condensing boiler, let alone a modulating one. It does. Only a cheaper, simpler more reliable boiler need be used. Sorry but no, as has been demonstrated before. It hasn't. You made things up, that was all. |
#19
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On Thu, 21 Jul 2005 00:17:04 +0100, "Doctor Drivel"
wrote: For quite a while. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. Only at the end. The operation temp of the store can be lowered to promote cooler operation. That's useless. Then one can't achieve decent storage for the energy needed for hot water If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boioer kW has bottomed out. There are boilers around with 5kW minimum. Alos means zone valve for zone, 3-ways, and other complexity. A store needs a number of controls around it as you very well know. the flow temperature can be allowed to fall substantially and the return even more so that the burner will tend to run continuously at low output rather than cycling at a higher temperature range to drive a store. Will not cycle heating the store as two stats are used. Will cylce directly on the rad circuits. Not if the minimum modulation level is reasonably low at 5kW or so. Problems always when fitting therostat rad valves. No there aren't. Use of a store makes good sense for DHW purposes if sufficient mains flow is available. For space heating, unless other energy sources are being added in, it defeats the designed in optimisation of the boiler which will then run less efficiently. Nonsense. Your department, I think. -- ..andy To email, substitute .nospam with .gl |
#20
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"Andy Hall" wrote in message news On Thu, 21 Jul 2005 00:17:04 +0100, "Doctor Drivel" wrote: For quite a while. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. Only at the end. The operation temp of the store can be lowered to promote cooler operation. That's useless. Then one can't achieve decent storage for the energy needed for hot water You size the cylinder to suit. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boioer kW has bottomed out. There are boilers around with 5kW minimum. Very few, and they still cycle, and still need zone vale and problems with TRVs. Also means zone valve for zone, 3-ways, and other complexity. A store needs a number of controls around it as you very well know. Simple stats and pumps, unless yiou have a state of the art one like me. the flow temperature can be allowed to fall substantially and the return even more so that the burner will tend to run continuously at low output rather than cycling at a higher temperature range to drive a store. Will not cycle heating the store as two stats are used. Will cycle when directly on the rad circuits. Not if the minimum modulation level is reasonably low at 5kW or so. Very rare, and only v expensive boilers and they still cycle. Problems always when fitting thermostat rad valves. No there aren't. There are. Use of a store makes good sense for DHW purposes if sufficient mains flow is available. For space heating, unless other energy sources are being added in, it defeats the designed in optimisation of the boiler which will then run less efficiently. Nonsense. Your department, I think. You just don't know. |
#21
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At one point I was looking at putting the boiler in an odd spot and the
waste-pipe flue would have made it just about the only choice, but this never came to pass Egremont. |
#22
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On Thu, 21 Jul 2005 01:19:36 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message news On Thu, 21 Jul 2005 00:17:04 +0100, "Doctor Drivel" wrote: For quite a while. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. Only at the end. The operation temp of the store can be lowered to promote cooler operation. That's useless. Then one can't achieve decent storage for the energy needed for hot water You size the cylinder to suit. Fine. However, you are always the person who promotes stores being able to be smaller because the water temperature is higher. You can't have it both ways as has been demonstrated many times. Next time the Albion rep. comes in, ask him to explain it to you. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boioer kW has bottomed out. There are boilers around with 5kW minimum. Very few, and they still cycle, and still need zone vale and problems with TRVs. Rubbish. There are no problems with TRVs at this level. Not if the minimum modulation level is reasonably low at 5kW or so. Very rare, and only v expensive boilers and they still cycle. Your understanding of heat storage and distribution is quite limited, isn't it.... If you drive radiators directly from a modulating boiler, when the heat requirement for the space is above the minimum boiler output, the boiler runs continuously. At the lower end, it also runs highly efficiently. When the heat requirement is at or below the minimum output level, the room thermostat will also play a part and will lock out the boiler until heat is next required. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. Ask one of the boiler reps to explain this to you. Actually don't - call their technical department. Problems always when fitting thermostat rad valves. No there aren't. There are. Perhaps you should use decent ones. Some TRV4s please. Use of a store makes good sense for DHW purposes if sufficient mains flow is available. For space heating, unless other energy sources are being added in, it defeats the designed in optimisation of the boiler which will then run less efficiently. Nonsense. Your department, I think. You just don't know. Plumbers merchants seem to be full of people behind the counter who spout about this or that in an "authoritative" way. Either they heard it from several heating guys who came in or were told by the manufacturer's rep as he was telling them about the latest promo trip to Eyebyeza. When are you going? -- ..andy To email, substitute .nospam with .gl |
#23
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"Andy Hall" wrote in message news On Thu, 21 Jul 2005 01:19:36 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message news On Thu, 21 Jul 2005 00:17:04 +0100, "Doctor Drivel" wrote: For quite a while. However, as the store warms, so will the return temperature, and to a point where the boiler is operating in the range of a conventional boiler. Only at the end. The operation temp of the store can be lowered to promote cooler operation. That's useless. Then one can't achieve decent storage for the energy needed for hot water You size the cylinder to suit. Fine. However, you are always the person who promotes stores being able to be smaller because the water temperature is higher. A store can be many things. You can combine the outout of boiler and the thermal store, moreso a heat bank than store, to improve DHW performace using a smaller storage vessel. You can promote greater condensing efficiency by lowering the store temperature and having alarger store, or a store matched to suit, etc. You can't have it both ways You can. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boiler kW has bottomed out. There are boilers around with 5kW minimum. Very few, and they still cycle, and still need zone vale and problems with TRVs. Rubbish. There are no problems with TRVs at this level. You require by-passes and a control interlock, which can be a bit involved, if you want TRVs on all rads. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. Not if the minimum modulation level is reasonably low at 5kW or so. Very rare, and only v expensive boilers and they still cycle. Your understanding of heat storage and distribution is quite limited, isn't it.... It is 110%. Just read and take note. You don't have to understand. Just accept it. If you drive radiators directly from a modulating boiler, When having two zones and TRVs on all rads complexities arise. 3kW is the least you will get from a boiler and those boilers are "very" expensive. When the heat requirement is at or below the minimum output level, the room thermostat will also play a part and will lock out the boiler until heat is next required. Using two CH zones off a thermal store using TRVs all around doesn't even require a room stat. Simple, by just instaling an Alpha pump. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. By inserting an outside weather compensator that dictates the temperature of the stored CH water in the thermla store, a condensing boiler operates to max efficiency. Simple to do. Plumbers merchants seem to be full of people behind the counter who spout about this or that in an "authoritative" way. Most have never heard of a thermal store, never mind how you apply it. You just don't know. |
#24
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On Thu, 21 Jul 2005 11:04:49 +0100, "Doctor Drivel"
wrote: A store can be many things. You can combine the outout of boiler and the thermal store, moreso a heat bank than store, to improve DHW performace using a smaller storage vessel. We've been around that one before. There is a short term effect with this which is dependent on the storage volume, the boiler capacity and the rate of use of heat. It does not improve performance in the sense of flow rate, and if used to make a worthwhile reduction in cylinder size, the stored energy may well run out reducing the performance and water temperature substantially - in effect creating a combi. Not a very interesting solution. You can promote greater condensing efficiency by lowering the store temperature and having alarger store, or a store matched to suit, etc. Condensing efficiency is improved by operating the boiler at a lower temperature not by increasing the size of the store. The effect of the latter is only to reduce cycling and is only important when, as is required with a store, the boiler runs at high temperature. That argument is more applicable to non-condensing boilers which are designed to run at high temperatures. You can't have it both ways You can. It's behind you. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boiler kW has bottomed out. There are boilers around with 5kW minimum. Very few, and they still cycle, and still need zone vale and problems with TRVs. Rubbish. There are no problems with TRVs at this level. You require by-passes and a control interlock, which can be a bit involved, if you want TRVs on all rads. The need for bypasses or not depends purely on the boiler and even if an external one is required, it is trivial. Likewise, control interlock in the form of a room thermostat is also trivial for those of average intelligence or above. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. This is pointless. A modulating condensing boiler can do this directly. Several have pump speed control as well so that the boiler burn rate, water flow rate and temperatures can all be optimised for maximum condensing efficiency and lack of cycling. Adding a store in the middle defeats that and is pointless for space heating applications. Not if the minimum modulation level is reasonably low at 5kW or so. Very rare, and only v expensive boilers and they still cycle. Your understanding of heat storage and distribution is quite limited, isn't it.... It is 110%. Just read and take note. You don't have to understand. Just accept it. Is that what the rep told you? He's a nice guy, isn't he? Don't forget to up that order for the Yorkshire fittings that he needs this month, will you.... If you drive radiators directly from a modulating boiler, When having two zones and TRVs on all rads complexities arise. 3kW is the least you will get from a boiler and those boilers are "very" expensive. There are several that will modulate down to low levels and will drive the radiators directly perfectly well. If your idea were so beneficial, it would be common practice and boilers would be designed to do it. As it is, they are optimised to heat cylinders (or stores) quickly for hot water purposes and to drive radiators directly. That is the main point of arranging for them to modulate. The vast majority do modulate, and very few are around that have fixed output, simply because a store is not the best way to implement a space heating solution unless other energy sources are being added in. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. By inserting an outside weather compensator that dictates the temperature of the stored CH water in the thermla store, a condensing boiler operates to max efficiency. Simple to do. If you do that and reduce the temperature in the store, it is no longer optimal for heating the water. Considering that with a modulating boiler, the temperatures can be run as low as 45/25 degrees to the radiators, the store is going to be pretty useless for heating the water. Plumbers merchants seem to be full of people behind the counter who spout about this or that in an "authoritative" way. Most have never heard of a thermal store, never mind how you apply it. Presumably they have in your branch now though? -- ..andy To email, substitute .nospam with .gl |
#25
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"Andy Hall" wrote in message ... On Thu, 21 Jul 2005 11:04:49 +0100, "Doctor Drivel" wrote: A store can be many things. You can combine the outout of boiler and the thermal store, moreso a heat bank than store, to improve DHW performace using a smaller storage vessel. We've been around that one before. There is a short term effect with this which is dependent on the storage volume, the boiler capacity and the rate of use of heat. Short term effect? What a BS term! This one is full of it. It does not improve performance in the sense of flow rate, What is he on about. and if used to make a worthwhile reduction in cylinder size, the stored energy may well run out reducing the performance and water temperature substantially - in effect creating a combi. Not a very interesting solution. This one hasn't a clue. You size the boiler output and then size the cylinder to support, to attain the level of DHW flow and volume required. You can promote greater condensing efficiency by lowering the store temperature and having alarger store, or a store matched to suit, etc. Condensing efficiency is improved by operating the boiler at a lower temperature not by increasing the size of the store. If the store is at a lower temp the stored energy is less. You size to suit. The effect of the latter is only to reduce cycling and is only important when, as is required with a store, the boiler runs at high temperature. Nonsense. That argument is more applicable to non-condensing boilers which are designed to run at high temperatures. Nonsense. You can't have it both ways You can. It's behind you. If the condensing boiler drives the radiators directly, This produces boiler cyling, once the boiler kW has bottomed out. There are boilers around with 5kW minimum. Very few, and they still cycle, and still need zone vale and problems with TRVs. Rubbish. There are no problems with TRVs at this level. You require by-passes and a control interlock, which can be a bit involved, if you want TRVs on all rads. The need for bypasses or not depends purely on the boiler and even if an external one is required, it is trivial. Another thing to go wrong and wreck your boiler. Likewise, control interlock in the form of a room thermostat is also trivial for those of average intelligence or above. A room stat cuts off the whole system or zone. Having TRVs on all rads and and Alpha pump, all off a store has no drawbacks. If you want TRVs on all rads with a boiler directly heating that rads, the control interlock becomes more complex and not standard. A major drawback. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. This is pointless. There is no central wall room stat to lmock ooff the zone. What is warm in one room maybe cold in another. A modulating condensing boiler can do this directly. Without a room stat? It can but complexity arises, and the control interlock and by-pass. The thermals store/Alpha pump is by far the best solution. Several have pump speed control as well so that the boiler burn rate, water flow rate and temperatures can all be optimised for maximum condensing efficiency and lack of cycling. All added complexity which can be avoided by using a thermal store. Adding a store in the middle defeats that and is pointless for space heating applications. Utter nonsense. If you drive radiators directly from a modulating boiler, When having two zones and TRVs on all rads complexities arise. 3kW is the least you will get from a boiler and those boilers are "very" expensive. There are several that will modulate down to low levels and will drive the radiators directly perfectly well. A few and are "very" expensive and highly complex. With a thermal store a cheap simple boiler can be used to better effect. If your idea were so beneficial, it would be common practice and boilers would be designed to do it. Sinmple boilesr are there and can do it. Main pressure water is far superior to tanks in lofts in performance. Yet if it was so good we would all be using it. Obvious. Yet even today new homes in estates are being built with low pressure tanks in the lofts. Why? Beats me. Most plumbers don't even know how thermal stores work. But, Gledhill Thermal Stores are making headway in the new build sector. As it is, they are optimised to heat cylinders (or stores) quickly for hot water purposes and to drive radiators directly. They are designed for the replacement market, which is now the largest sector. That is the main point of arranging for them to modulate. No. It is to mate onto an existing system. The vast majority do modulate, and very few are around that have fixed output, simply because a store is not the best way to implement a space heating solution unless other energy sources are being added in. As indicated to you the store is the best way. Simpler, more effective, and all rooms can have "fully" independent temp control. On warm up the rads are hot instantly. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. By inserting an outside weather compensator that dictates the temperature of the stored CH water in the thermla store, a condensing boiler operates to max efficiency. Simple to do. If you do that and reduce the temperature in the store, it is no longer optimal for heating the water. I think you mean DHW. You only have the lower CH section controlled by the compensator. The upper DHW section can be 70, 75, 80C. The upper and lower sectionnwill be at too very different temperatures, with the lower controlled by the outside waether compensator. This lower CH section could be as low as 35C and the boiler operates in a low temperature high efficient environment. A cheap simple boiler too, no compe expensive mother... Considering that with a modulating boiler, the temperatures can be run as low as 45/25 degrees to the radiators, the store is going to be pretty useless for heating the water. See just above, DHW. Plumbers merchants seem to be full of people behind the counter who spout about this or that in an "authoritative" way. Most have never heard of a thermal store, never mind how you apply it. Presumably they have in your branch now though? ...Lord Hall wears a top hat, this is so ...Lord Hall thinks the top hat is all the go ...Lord Hall wears the top hat all the week ...and the dead mouse upon his lip don't half reak ...he doesn't know it's there as dead mice don't squeak |
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On Thu, 21 Jul 2005 14:26:13 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message .. . On Thu, 21 Jul 2005 11:04:49 +0100, "Doctor Drivel" wrote: A store can be many things. You can combine the outout of boiler and the thermal store, moreso a heat bank than store, to improve DHW performace using a smaller storage vessel. We've been around that one before. There is a short term effect with this which is dependent on the storage volume, the boiler capacity and the rate of use of heat. Short term effect? What a BS term! This one is full of it. There may well be a British Standard covering this area. It does not improve performance in the sense of flow rate, What is he on about. and if used to make a worthwhile reduction in cylinder size, the stored energy may well run out reducing the performance and water temperature substantially - in effect creating a combi. Not a very interesting solution. This one hasn't a clue. You size the boiler output and then size the cylinder to support, to attain the level of DHW flow and volume required. You are obfuscating again. You can promote greater condensing efficiency by lowering the store temperature and having alarger store, or a store matched to suit, etc. Condensing efficiency is improved by operating the boiler at a lower temperature not by increasing the size of the store. If the store is at a lower temp the stored energy is less. You size to suit. Obviously, but there is a lower reasonable limit. One needs to have the store temperature at 60 degrees to produce hot water at a reasonable temperature. The effect of the latter is only to reduce cycling and is only important when, as is required with a store, the boiler runs at high temperature. Nonsense. No it isn't. Cycling at high temperature implies far more loss of energy than it does at lower temperatures. That argument is more applicable to non-condensing boilers which are designed to run at high temperatures. Nonsense. Nope. The need for bypasses or not depends purely on the boiler and even if an external one is required, it is trivial. Another thing to go wrong and wreck your boiler. Tripe. Likewise, control interlock in the form of a room thermostat is also trivial for those of average intelligence or above. A room stat cuts off the whole system or zone. Having TRVs on all rads and and Alpha pump, all off a store has no drawbacks. The drawback is putting the store in the middle of the control system forcing the boiler to operate outside its optimal range for space heating as well as for DHW. If you want TRVs on all rads with a boiler directly heating that rads, the control interlock becomes more complex and not standard. A major drawback. Rubbish. This is entirely the standard implementation used in millions of homes. TRVs on all radiators except one located in the room with room thermostat. Surely you are not trying to claim that room thermostats are complex are you? Ask the Danfoss rep. to explain how they work next time he's in. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. This is pointless. There is no central wall room stat to lmock ooff the zone. What is warm in one room maybe cold in another. A modulating condensing boiler can do this directly. Without a room stat? It can but complexity arises, and the control interlock and by-pass. The thermals store/Alpha pump is by far the best solution. You are spouting nonsense as has already been explained. Several have pump speed control as well so that the boiler burn rate, water flow rate and temperatures can all be optimised for maximum condensing efficiency and lack of cycling. All added complexity which can be avoided by using a thermal store. It is no more added complexity to have a pump which is controlled by the boiler electronics vs. an external Alpha. The Alpha is useful for cases where the boiler is incapable of stepped or proportional control of the pump. In cases where the boiler electronics can control the pump - e.g. the Celsius and Micromat among others then it makes sense to use it. In effect what you are suggesting is an arrangement where you disable the designed control system of the boiler by putting a store between it and the load that it can so easily control, to run the boiler outside of its optimal range of temperature and then to attempt to redress the issue by fitting an Alpha, which good though it is, only operates based on detecting flow/pressure and not under control of the boiler, which also knows aout temperature and optimisation of that. It's a dumb idea. Adding a store in the middle defeats that and is pointless for space heating applications. Utter nonsense. Yes it is utter nonsense unless you are trying to introduce energy from another source. If you drive radiators directly from a modulating boiler, When having two zones and TRVs on all rads complexities arise. 3kW is the least you will get from a boiler and those boilers are "very" expensive. There are several that will modulate down to low levels and will drive the radiators directly perfectly well. A few and are "very" expensive and highly complex. There is a burner, a heat exchanger, a board of electronics, a fan, a gas valve and perhaps a pump. This is not "highly complex" any more than any decent quality modulating boiler. With a thermal store a cheap simple boiler can be used to better effect. As long as the boiler is a non-condensing one, possibly. If your idea were so beneficial, it would be common practice and boilers would be designed to do it. Sinmple boilesr are there and can do it. Main pressure water is far superior to tanks in lofts in performance. Provided that the water supply is adequate. Yet if it was so good we would all be using it. Obvious. Yet even today new homes in estates are being built with low pressure tanks in the lofts. Why? Beats me. Most plumbers don't even know how thermal stores work. You must be a plumber on the side then, as well as working in a merchant. But, Gledhill Thermal Stores are making headway in the new build sector. As it is, they are optimised to heat cylinders (or stores) quickly for hot water purposes and to drive radiators directly. They are designed for the replacement market, which is now the largest sector. That is the main point of arranging for them to modulate. No. It is to mate onto an existing system. Radiators are radiators. If the radiator system is designed to have been run from a conventional 82/70 boiler, then at certain times of the year, high temperatures will be needed. If it sized to give more output and work with 70/50 from a condensing boiler then fine as well and it will be more efficient. Either way a modulating boiler is beneficial if it is condensing. The vast majority do modulate, and very few are around that have fixed output, simply because a store is not the best way to implement a space heating solution unless other energy sources are being added in. As indicated to you the store is the best way. Simpler, more effective, and all rooms can have "fully" independent temp control. It isn't simpler because you are adding a store, pump and controls. On warm up the rads are hot instantly. The key thing is the radiator output in proportion to that required to address the heat loss of the room. Since many boilers have high peak outputs anyway, what you describe is at best a second order effect. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. By inserting an outside weather compensator that dictates the temperature of the stored CH water in the thermla store, a condensing boiler operates to max efficiency. Simple to do. If you do that and reduce the temperature in the store, it is no longer optimal for heating the water. I think you mean DHW. You only have the lower CH section controlled by the compensator. The upper DHW section can be 70, 75, 80C. The upper and lower sectionnwill be at too very different temperatures, with the lower controlled by the outside waether compensator. This lower CH section could be as low as 35C and the boiler operates in a low temperature high efficient environment. This is waffle. Unless you split the store into discrete and separate sections or have two stores, you can't achieve any accuracy of control, especially as you only have one source of heat into the store. -- ..andy To email, substitute .nospam with .gl |
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"Andy Hall" wrote in message ... On Thu, 21 Jul 2005 14:26:13 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message .. . On Thu, 21 Jul 2005 11:04:49 +0100, "Doctor Drivel" wrote: A store can be many things. You can combine the outout of boiler and the thermal store, moreso a heat bank than store, to improve DHW performace using a smaller storage vessel. We've been around that one before. There is a short term effect with this which is dependent on the storage volume, the boiler capacity and the rate of use of heat. Short term effect? What a BS term! This one is full of it. There may well be a British Standard covering this area. A BS covering BS? Mmmmm It does not improve performance in the sense of flow rate, What is he on about. and if used to make a worthwhile reduction in cylinder size, the stored energy may well run out reducing the performance and water temperature substantially - in effect creating a combi. Not a very interesting solution. This one hasn't a clue. You size the boiler output and then size the cylinder to support, to attain the level of DHW flow and volume required. You are obfuscating again. Quite clear. You can promote greater condensing efficiency by lowering the store temperature and having alarger store, or a store matched to suit, etc. Condensing efficiency is improved by operating the boiler at a lower temperature not by increasing the size of the store. If the store is at a lower temp the stored energy is less. You size to suit. Obviously, but there is a lower reasonable limit. One needs to have the store temperature at 60 degrees to produce hot water at a reasonable temperature. The effect of the latter is only to reduce cycling and is only important when, as is required with a store, the boiler runs at high temperature. Nonsense. No it isn't. Cycling at high temperature implies far more loss of energy than it does at lower temperatures. Nonsense. That argument is more applicable to non-condensing boilers which are designed to run at high temperatures. Nonsense. Nope. The need for bypasses or not depends purely on the boiler and even if an external one is required, it is trivial. Another thing to go wrong and wreck your boiler. Tripe. Likewise, control interlock in the form of a room thermostat is also trivial for those of average intelligence or above. A room stat cuts off the whole system or zone. Having TRVs on all rads and and Alpha pump, all off a store has no drawbacks. The drawback is putting the store in the middle of the control system forcing the boiler to operate outside its optimal range for space heating as well as for DHW. Nonsense. The store is a great neutral point asset. The boiler work can work at very low temperatures when a weather compensator is attached to the CH section. This also reduces boiler cycling too. A great assset. If you want TRVs on all rads with a boiler directly heating that rads, the control interlock becomes more complex and not standard. A major drawback. Rubbish. This is entirely the standard implementation used in millions of homes. TRVs on all radiators except one located in the room with room thermostat. You can't read. I said "TRVs on all rads", not one left open that switches the system off when some rooms are calling for heat. Silly idea. Surely you are not trying to claim that room thermostats are complex are you? Ask the Danfoss rep. to explain how they work next time he's in. With a boiler directly heating rads if all rads have TRVs, complexity arises to ensure the boiler has flow though it at all times. A thermal store using Alpha pumps eliminates this complexity. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. This is pointless. There is no central wall room stat to lmock ooff the zone. What is warm in one room maybe cold in another. A modulating condensing boiler can do this directly. Without a room stat? It can but complexity arises, and the control interlock and by-pass. The thermals store/Alpha pump is by far the best solution. You are spouting nonsense as has already been explained. You lack comprehension. There is complexity using a thermals store, an Alpha pumps and TRVs on all rads. No room stat required, no by-pass no flow switches, none of any of that. Alpha are also quiet in operation as they vary the speed. Several have pump speed control as well so that the boiler burn rate, water flow rate and temperatures can all be optimised for maximum condensing efficiency and lack of cycling. All added complexity which can be avoided by using a thermal store. It is no more added complexity to have a pump which is controlled by the boiler electronics vs. an external Alpha. Much more needless complexity. In effect what you are suggesting is an arrangement where you disable the designed control system of the boiler by putting a store between it and the load that it can so easily control, You have a boiler without a complicated control system. Simpler, cheaper, longer lasting and more reliable. to run the boiler outside of its optimal range of temperature The boiler runs at the temperatures dicted by the buiklding load dictated by a weather compensator. The compensator heats the stored water in te CH section of the store. and then to attempt to redress the issue by fitting an Alpha, which good though it is, only operates based on detecting flow/pressure and not under control of the boiler, which also knows aout temperature and optimisation of that. The Alpha does not have to be under the control of the boiler. It is better separated from the boiler totally and run from a thermal store. Optimisation of temperature is best done via a weather compensator, not the boiler. It's a dumb idea. You haven't a clue. Adding a store in the middle defeats that and is pointless for space heating applications. Utter nonsense. Yes it is utter nonsense unless you are trying to introduce energy from another source. If you drive radiators directly from a modulating boiler, When having two zones and TRVs on all rads complexities arise. 3kW is the least you will get from a boiler and those boilers are "very" expensive. There are several that will modulate down to low levels and will drive the radiators directly perfectly well. A few and are "very" expensive and highly complex. There is a burner, a heat exchanger, a board of electronics, a fan, a gas valve and perhaps a pump. This is not "highly complex" any more than any decent quality modulating boiler. With a thermal store a cheap simple boiler can be used to better effect. As long as the boiler is a non-condensing one, possibly. Nope. A condesning boiler is fully optimised. If your idea were so beneficial, it would be common practice and boilers would be designed to do it. Simple boilers are there and can do it. Mains pressure water is far superior to tanks in lofts in performance. Provided that the water supply is adequate. Yet if it was so good we would all be using it. Obvious. Yet even today new homes in estates are being built with low pressure tanks in the lofts. Why? Beats me. Most plumbers don't even know how thermal stores work. You must be a plumber on the side then, as well as working in a merchant. Not a plumber. No drains and gutters. But, Gledhill Thermal Stores are making headway in the new build sector. As it is, they are optimised to heat cylinders (or stores) quickly for hot water purposes and to drive radiators directly. They are designed for the replacement market, which is now the largest sector. That is the main point of arranging for them to modulate. No. It is to mate onto an existing system. Radiators are radiators. If the radiator system is designed to have been run from a conventional 82/70 boiler, then at certain times of the year, high temperatures will be needed. If it sized to give more output and work with 70/50 from a condensing boiler then fine as well and it will be more efficient. Either way a modulating boiler is beneficial if it is condensing. If directly attached to an existing system. The vast majority do modulate, and very few are around that have fixed output, simply because a store is not the best way to implement a space heating solution unless other energy sources are being added in. As indicated to you the store is the best way. Simpler, more effective, and all rooms can have "fully" independent temp control. It isn't simpler because you are adding a store, pump and controls. No zone valves, just simple pumps. On warm up the rads are hot instantly. The key thing is the radiator output in proportion to that required to address the heat loss of the room. The TRVs do that. Independent room control "in all rooms" Since many boilers have high peak outputs anyway, what you describe is at best a second order effect. More BS. Any switching of the boiler will be on a very long interval, just as it is with a store. However, since this is occuring at a much lower power level than happens when driving a store, there is less energy waste at the time the boiler fires up. It will also be working directly in its most efficient temperature range. By inserting an outside weather compensator that dictates the temperature of the stored CH water in the thermla store, a condensing boiler operates to max efficiency. Simple to do. If you do that and reduce the temperature in the store, it is no longer optimal for heating the water. I think you mean DHW. You only have the lower CH section controlled by the compensator. The upper DHW section can be 70, 75, 80C. The upper and lower sectionnwill be at too very different temperatures, with the lower controlled by the outside waether compensator. This lower CH section could be as low as 35C and the boiler operates in a low temperature high efficient environment. This is waffle. Read again. You can move your lips. Unless you split the store into discrete and separate sections or have two stores, you can't achieve any accuracy of control, especially as you only have one source of heat into the store. The store can be split into two temperature zone with the same cylidner, both temp zones heated via the same heat souces. ...Lord Hall doesn't know, a man who has no clue ...he has no clue about the things which are known to me and you ...24/7 he is vacant in his head ...no knoweldge, reason, logic, this must be said ...drivel and babble just comes so ...relentless, incoherrent in its flow ...it's time take no notice of this hot head babbling fool ...just laugh and smile and thank the Lord you are sane and cool |
#28
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On Thu, 21 Jul 2005 22:43:16 +0100, "Doctor Drivel"
wrote: It does not improve performance in the sense of flow rate, What is he on about. and if used to make a worthwhile reduction in cylinder size, the stored energy may well run out reducing the performance and water temperature substantially - in effect creating a combi. Not a very interesting solution. This one hasn't a clue. You size the boiler output and then size the cylinder to support, to attain the level of DHW flow and volume required. You are obfuscating again. Quite clear. I thought so. Likewise, control interlock in the form of a room thermostat is also trivial for those of average intelligence or above. A room stat cuts off the whole system or zone. Having TRVs on all rads and and Alpha pump, all off a store has no drawbacks. The drawback is putting the store in the middle of the control system forcing the boiler to operate outside its optimal range for space heating as well as for DHW. Nonsense. The store is a great neutral point asset. Where do you get these lines? It's a neutral point asset *perhaps* if there is a requirement to introduce heat from solar etc. The boiler work can work at very low temperatures when a weather compensator is attached to the CH section. This also reduces boiler cycling too. A great assset. Waffle. You know full well that this only does anything worthwhile if there were separate heating and DHW stores. Since the former is pointless anyway, the whole thing goes full circle to where we came in. If you want TRVs on all rads with a boiler directly heating that rads, the control interlock becomes more complex and not standard. A major drawback. Rubbish. This is entirely the standard implementation used in millions of homes. TRVs on all radiators except one located in the room with room thermostat. You can't read. I said "TRVs on all rads", not one left open that switches the system off when some rooms are calling for heat. Silly idea. As you very well know, the radiator in the room without TRV is adjusted such that the rooms with TRVs are satisfied for heat before the thermostat turns off. Ask the rep to help you with this one. Surely you are not trying to claim that room thermostats are complex are you? Ask the Danfoss rep. to explain how they work next time he's in. With a boiler directly heating rads if all rads have TRVs, complexity arises to ensure the boiler has flow though it at all times. A thermal store using Alpha pumps eliminates this complexity. The whole thing is pointless and unnecessary in the first place, so adding self adjusting pumps is a separate issue. If a bypass is required, it can easily be implemented anyway. Taking the rad circuits from the store you can have TRVs on all rads, by only having a Grundfos Alpha on the circuit. You can have two CH zones directly off the store both with just an Alpha pump and TRVs on all rads. This is pointless. There is no central wall room stat to lmock ooff the zone. What is warm in one room maybe cold in another. A modulating condensing boiler can do this directly. Without a room stat? It can but complexity arises, and the control interlock and by-pass. The thermals store/Alpha pump is by far the best solution. You are spouting nonsense as has already been explained. You lack comprehension. There is complexity using a thermals store, an Alpha pumps and TRVs on all rads. yes I know. No room stat required, no by-pass no flow switches, none of any of that. So what. Alpha are also quiet in operation as they vary the speed. I know. I have one, but not for that application Several have pump speed control as well so that the boiler burn rate, water flow rate and temperatures can all be optimised for maximum condensing efficiency and lack of cycling. All added complexity which can be avoided by using a thermal store. It is no more added complexity to have a pump which is controlled by the boiler electronics vs. an external Alpha. Much more needless complexity. Ask the rep to explain to you about system boilers. In effect what you are suggesting is an arrangement where you disable the designed control system of the boiler by putting a store between it and the load that it can so easily control, You have a boiler without a complicated control system. Simpler, cheaper, longer lasting and more reliable. There are loads of extra discrete components in your scheme and a bunch of compromises that make no sense when a modulating condensing boiler is used. A pump is a pump whether it is fitted inside a boiler or outside. The extra thermostats, relays, switches, pumps and other paraphernalia are superfluous if the system is designed as the boiler manufacturers intended and not as a Heath Robinson project like you are suggesting. to run the boiler outside of its optimal range of temperature The boiler runs at the temperatures dicted by the buiklding load dictated by a weather compensator. The compensator heats the stored water in te CH section of the store. Really? How does it manage to do that? They are normally a sensor on the wall outside plus some electronics. Are you running pipes to the outside wall now? and then to attempt to redress the issue by fitting an Alpha, which good though it is, only operates based on detecting flow/pressure and not under control of the boiler, which also knows aout temperature and optimisation of that. The Alpha does not have to be under the control of the boiler. It is better separated from the boiler totally and run from a thermal store. It is designed to be standalone and for certain applications is useful. However, having flow rate controlled by the same controller as the boiler firing rate and temperatures will by definition be a superior solution simply because the control systems are closed loop and not disassociated as you are suggesting. Optimisation of temperature is best done via a weather compensator, not the boiler. Optimisation of temperature is best done with an outside temperature sensor connected directly to the boiler electronics and taken into account by them when directly controlling the pump and burn rate. This also optimises efficiency. .. There is a burner, a heat exchanger, a board of electronics, a fan, a gas valve and perhaps a pump. This is not "highly complex" any more than any decent quality modulating boiler. With a thermal store a cheap simple boiler can be used to better effect. As long as the boiler is a non-condensing one, possibly. Nope. A condesning boiler is fully optimised. Yes, to drive a space heating load directly. You must be a plumber on the side then, as well as working in a merchant. Not a plumber. No drains and gutters. Ah. Probably best. Hard to cut with a junior hacksaw. But, Gledhill Thermal Stores are making headway in the new build sector. As it is, they are optimised to heat cylinders (or stores) quickly for hot water purposes and to drive radiators directly. They are designed for the replacement market, which is now the largest sector. That is the main point of arranging for them to modulate. No. It is to mate onto an existing system. Radiators are radiators. If the radiator system is designed to have been run from a conventional 82/70 boiler, then at certain times of the year, high temperatures will be needed. If it sized to give more output and work with 70/50 from a condensing boiler then fine as well and it will be more efficient. Either way a modulating boiler is beneficial if it is condensing. If directly attached to an existing system. Even if attached to a newly designed system with larger heat emitters. The vast majority do modulate, and very few are around that have fixed output, simply because a store is not the best way to implement a space heating solution unless other energy sources are being added in. As indicated to you the store is the best way. Simpler, more effective, and all rooms can have "fully" independent temp control. It isn't simpler because you are adding a store, pump and controls. No zone valves, just simple pumps. "simple" pumps. Alpha. Hmm... On warm up the rads are hot instantly. The key thing is the radiator output in proportion to that required to address the heat loss of the room. The TRVs do that. Independent room control "in all rooms" Since many boilers have high peak outputs anyway, what you describe is at best a second order effect. More BS. Exactly. That's why I highlighted the error of your ways. Unless you split the store into discrete and separate sections or have two stores, you can't achieve any accuracy of control, especially as you only have one source of heat into the store. The store can be split into two temperature zone with the same cylidner, both temp zones heated via the same heat souces. There is very little splitting possible because the water will naturally convect and form a single temperature gradient. This was first form physics in grammar school or in my case already covered in the penultimate year of primary school. -- ..andy To email, substitute .nospam with .gl |
#29
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"Andy Hall" wrote in message ... Nonsense. The store is a great neutral point asset. Where do you get these lines? From brilliant knowledge and experience. The boiler work can work at very low temperatures when a weather compensator is attached to the CH section. This also reduces boiler cycling too. A great assset. Waffle. snip drivel If you want TRVs on all rads with a boiler directly heating that rads, the control interlock becomes more complex and not standard. A major drawback. Rubbish. This is entirely the standard implementation used in millions of homes. TRVs on all radiators except one located in the room with room thermostat. You can't read. I said "TRVs on all rads", not one left open that switches the system off when some rooms are calling for heat. Silly idea. As you very well know, the radiator in the room without TRV is adjusted such that the rooms with TRVs are satisfied for heat before the thermostat turns off. Then there is the boioer interlock. Surely you are not trying to claim that room thermostats are complex are you? Ask the Danfoss rep. to explain how they work next time he's in. With a boiler directly heating rads if all rads have TRVs, complexity arises to ensure the boiler has flow though it at all times. A thermal store using Alpha pumps eliminates this complexity. The whole thing is pointless and unnecessary in the first place, so adding self adjusting pumps is a separate issue. If a bypass is required, it can easily be implemented anyway. No by-pass, which could go wrong and wreck your boioer, with thermal store. Alpha are also quiet in operation as they vary the speed. I know. I have one, but not for that application Then you should use it on a thermal store. In effect what you are suggesting is an arrangement where you disable the designed control system of the boiler by putting a store between it and the load that it can so easily control, You have a boiler without a complicated control system. Simpler, cheaper, longer lasting and more reliable. There are loads of extra discrete components in your scheme Few components. It is simple and highly effective, reliable and efficient. and a bunch of compromises No compromises whatsoever. All aspects: CH, DHW and Boiler are optimised. that make no sense when a modulating condensing boiler is used. No need for such complexity when thermal store is used. Modulating boilers in themselves are compromises. A pump is a pump whether it is fitted inside a boiler or outside. Some modulates to system pressure - Alpha. The extra thermostats, relays, switches, pumps and other paraphernalia are superfluous if the system is designed as the boiler manufacturers intended and not as a Heath Robinson project like you are suggesting. This is utterly pathetic, bending your system to suit the whims of a boiler manufacturer. A designer has control of a system using a thermal store. The store a neutral point at the centre of the system. The boiler is heat source, that is all. The one aspect of the system can be optimised fro the rads which also optimises the boiler performance - by using a weather compensator. to run the boiler outside of its optimal range of temperature The boiler runs at the temperatures dicted by the building load dictated by a weather compensator. The compensator heats the stored water in the CH section of the store. Really? How does it manage to do that? Controlling a cheap simple boiler and then to attempt to redress the issue by fitting an Alpha, which good though it is, only operates based on detecting flow/pressure and not under control of the boiler, which also knows aout temperature and optimisation of that. The Alpha does not have to be under the control of the boiler. It is better separated from the boiler totally and run from a thermal store. It is designed to be standalone and for certain applications is useful. In this is it brilliant and ideal and no need for a boiler to be involved. However, having flow rate controlled by the same controller as the boiler firing rate and temperatures will by definition be a superior solution simply because the control systems are closed loop and not disassociated as you are suggesting. Not a superior solution. The weather compensator decides the rads flow temperature and then ensures a store of water is at that temperature. A simple boiler is used to heat the stored water to the desired temperature, maintain the boiler at optimum operating condition for efficiency, which also eliminates boiler cycling. The mass of water ensures this. The boilers is on full flow all the time as no rads with thermo valves to close down the flow. Always at the right optimised temp for the system. Optimisation of temperature is best done via a weather compensator, not the boiler. Optimisation of temperature is best done with an outside temperature sensor connected directly to the boiler electronics and taken into account by them when directly controlling the pump and burn rate. This also optimises efficiency. Not so. Best is have a mass of water at the correct temperature for the rads dictated by the outside weather compensator. This eliminates: - boiler cycling totally. - boiler interlocks - by-passes - room stats that control a system or heating zone Promotes: - efficient optimum boiler operation, always operating at the lowest temperature set by the weather compensator - independent room temperature control, not overriden by overall system temperature control - quiet CH zone operation - instant heat at rads - Instant DHW - few overall part - no complex parts, apart from weather compensator, which is not complex by todays stadards. - simple parts: simple boiler, simple thermo rad valves simple pumps - elmimation of troublesome parts - etc - etc. No zone valves, just simple pumps. "simple" pumps. Alpha. Hmm... Simple and self contained. Just treated as any other pump. Unless you split the store into discrete and separate sections or have two stores, you can't achieve any accuracy of control, especially as you only have one source of heat into the store. The store can be split into two temperature zone with the same cylidner, both temp zones heated via the same heat souces. There is very little splitting possible because the water will naturally convect and form a single temperature gradient. Nonsense. Distinct tem,temperature zone scan be maintained. ...Lord Hall doesn't know, a man who has no clue ...he has no clue about the things which are known to me and you ...24/7 he is vacant in his head ...no knoweldge, reason, logic, this must be said ...drivel and babble just comes so ...relentless, incoherrent in its flow ...it's time take no notice of this hot head babbling fool ...just laugh and smile and thank the Lord you are sane and cool |
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On Fri, 22 Jul 2005 00:20:26 +0100, "Doctor Drivel"
wrote: No by-pass, which could go wrong and wreck your boioer, with thermal store. Now you really are scratching around. Do you have a dud batch that you are trying to return to the manufacturer or something? Few components. It is simple and highly effective, reliable and efficient. and a bunch of compromises No compromises whatsoever. All aspects: CH, DHW and Boiler are optimised. Not with your arrangement. that make no sense when a modulating condensing boiler is used. No need for such complexity when thermal store is used. Modulating boilers in themselves are compromises. Everything's a compromise. Defeating control systems unnecessarily is pointless. A pump is a pump whether it is fitted inside a boiler or outside. Some modulates to system pressure - Alpha. Sigh...... The extra thermostats, relays, switches, pumps and other paraphernalia are superfluous if the system is designed as the boiler manufacturers intended and not as a Heath Robinson project like you are suggesting. This is utterly pathetic, bending your system to suit the whims of a boiler manufacturer. Who knows how to correctly match his heat source and control system to a standard load. A designer has control of a system using a thermal store. You are attempting to gild a lily and painting it with ****e instead. The store a neutral point at the centre of the system. The boiler is heat source, that is all. That depends on the boiler. If it's one of the budget range that you sell because you get free trips to Eyebyeza then quite possibly. If it's a decent quality one with integral controlled pump, conrolled modulating burner and weather compensation then it is a great deal more. I am surprised that you even tried that one. Actually, no I'm not. The one aspect of the system can be optimised fro the rads which also optimises the boiler performance - by using a weather compensator. Waffle. It is designed to be standalone and for certain applications is useful. In this is it brilliant and ideal and no need for a boiler to be involved. However, having flow rate controlled by the same controller as the boiler firing rate and temperatures will by definition be a superior solution simply because the control systems are closed loop and not disassociated as you are suggesting. Not a superior solution. The weather compensator decides the rads flow temperature and then ensures a store of water is at that temperature. A simple boiler is used to heat the stored water to the desired temperature, maintain the boiler at optimum operating condition for efficiency, which also eliminates boiler cycling. The mass of water ensures this. The boilers is on full flow all the time as no rads with thermo valves to close down the flow. Always at the right optimised temp for the system. Complete waffle. What desired temperature? You still haven't explained how you propose to optimise for the maximum efficiency of the boiler (low temperatures), the requirement for the store to be at high temperature for DHW production and the needs of space heating (variable to match the weather conditions. You can't achieve all of these objectives with a single store. Two would be required and then the boiler would still be run non optimally for space heating. Optimisation of temperature is best done via a weather compensator, not the boiler. Optimisation of temperature is best done with an outside temperature sensor connected directly to the boiler electronics and taken into account by them when directly controlling the pump and burn rate. This also optimises efficiency. Not so. Best is have a mass of water at the correct temperature for the rads dictated by the outside weather compensator. This eliminates: - boiler cycling totally. No it doesn't. - boiler interlocks No it doesn't - by-passes Irrelevant. - room stats that control a system or heating zone Big deal. Promotes: - efficient optimum boiler operation, always operating at the lowest temperature set by the weather compensator No it doesn't unless two stores are used and even then the boiler does not have the opportunity to modulate down to most optimum rate during space heating because the control is defeated. - independent room temperature control, not overriden by overall system temperature control Achievable whatever. - quiet CH zone operation Achievable whatever - instant heat at rads Second order effect on rate of rise in room temperature - Instant DHW Achievable in many other ways as well and a store is a good way for this part, just not for space heating with this type of boiler. - few overall part highly debatable - no complex parts, apart from weather compensator, which is not complex by todays stadards. No complex parts either way. - simple parts: simple boiler, simple thermo rad valves simple pumps the discussion is about a modulating boiler not a conventional non condensing one. Unless you split the store into discrete and separate sections or have two stores, you can't achieve any accuracy of control, especially as you only have one source of heat into the store. The store can be split into two temperature zone with the same cylidner, both temp zones heated via the same heat souces. There is very little splitting possible because the water will naturally convect and form a single temperature gradient. Nonsense. Distinct tem,temperature zone scan be maintained. Even you (actually especially you) can't defy physics. You cannot control a temperature gradient in a single body of water in two separate and discrete entities which is what you are suggesting here. It will naturally convect to form a single one. If you wanted to tap off at a certain point on a cylinder to get a lower temperature or deliver a lower temperature in a fixed way, that is reasonable. However, you have been suggesting that the needs of DHW production (80 degree storage) and spae heating with weather compensated temperature control of the stored water is possible in a single vessel. It very obviously isn't -- ..andy To email, substitute .nospam with .gl |
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"Andy Hall" wrote in message ... On Fri, 22 Jul 2005 00:20:26 +0100, "Doctor Drivel" wrote: No by-pass, which could go wrong and wreck your boiler, with thermal store. Now you really are scratching around. Not at all. Also they open up and defeat the object of a condensing boiler and greatly raise the return temperature. It is clear you are very silly snip garbage by Lord Hall ...Lord Hall doesn't know, a man who has no clue ...he has no clue about the things which are known to me and you ...24/7 he is vacant in his head ...no knoweldge, reason, logic, this must be said ...drivel and babble just comes so ...relentless, incoherrent in its flow ...it's time take no notice of this hot head babbling fool ...just laugh and smile and thank the Lord you are sane and cool |
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On Fri, 22 Jul 2005 01:53:19 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message .. . On Fri, 22 Jul 2005 00:20:26 +0100, "Doctor Drivel" wrote: No by-pass, which could go wrong and wreck your boiler, with thermal store. Now you really are scratching around. Not at all. Also they open up and defeat the object of a condensing boiler and greatly raise the return temperature. You know very well that an ABV is set to only open when the circuit flows are stopped entirely. Ask the rep to explain it to you. A tub of Boss White please. -- ..andy To email, substitute .nospam with .gl |
#33
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"Andy Hall" wrote in message ... On Fri, 22 Jul 2005 01:53:19 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message .. . On Fri, 22 Jul 2005 00:20:26 +0100, "Doctor Drivel" wrote: No by-pass, which could go wrong and wreck your boiler, with thermal store. Now you really are scratching around. Not at all. Also they open up and defeat the object of a condensing boiler and greatly raise the return temperature. You know very well that an ABV is set to only open when the circuit flows are stopped entirely. The hall rad is balanced it may not pass enough flow for the boiler, so the by-pass opens. Best avoid a by-pass and use a thermal store/heat bank and an Alpha pump. ..."self abuse"! Lord Hall doth shout ...he heavily indudges, of this no doubt ...of this act he does hanker ...that's why his mates call him the DIY ****** |
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On Fri, 22 Jul 2005 14:48:18 +0100, "Doctor Drivel"
wrote: "Andy Hall" wrote in message .. . On Fri, 22 Jul 2005 01:53:19 +0100, "Doctor Drivel" wrote: "Andy Hall" wrote in message .. . On Fri, 22 Jul 2005 00:20:26 +0100, "Doctor Drivel" wrote: No by-pass, which could go wrong and wreck your boiler, with thermal store. Now you really are scratching around. Not at all. Also they open up and defeat the object of a condensing boiler and greatly raise the return temperature. You know very well that an ABV is set to only open when the circuit flows are stopped entirely. The hall rad is balanced it may not pass enough flow for the boiler, so the by-pass opens. Best avoid a by-pass and use a thermal store/heat bank and an Alpha pump. Don't be silly. This is a non issue. 1) There is nothing that says that the radiator in the hall has to be used as the non-TRV one nor that it would be of a size where there is insufficient flow. 2) It is perfectly possible to choose living room or other locations as the non-TRV location. 3) TRVs do not close off completely until the room temperature is above the set point. They close off gradually with temperature and reduce the flow first. In order to make sure that the temperatures in rooms with TRV achieve a desired level, the TRVs are set to make sure that that happens close to when the room thermostat becomes satisfied. I know that you are clutching at straws, but it is more typical to use hemp, not straw in combination with Boss White for thread sealing. A plastic pipe cutter and three lengths of 15mm barrier tube please... -- ..andy To email, substitute .nospam with .gl |
#35
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For a Thermal Store - you are right it is far better to turn off
modulation - you can do this by a simple removal of a bridge on most boilers. I have a Baxi 100HE/Barcelona just pull out one bridge to turn off modulation, and also pull 2nd bridge to put in in high power mode. most boilers are the same. |
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