 |
|
| 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. |
| Reply |
|
|
LinkBack | Thread Tools | Display Modes |
|
#1
|
|||
|
|||
single pipe central heating
Hi everyone,
i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... |
|
#2
|
|||
|
|||
|
"BAHADIR" wrote in message om... Hi everyone, i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... http://www.diydata.com/planning/cent...g/pipework.htm |
|
#3
|
|||
|
|||
|
"Dave Jones" wrote in message ... "BAHADIR" wrote in message om... Hi everyone, i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... http://www.diydata.com/planning/cent...g/pipework.htm I note the above site talks about pressure relieve valve. I believe in Sweden ( could also be Denmark) they have automatic pressure relieve valves built in the their thermostatic valves so if all the thermostatic valves are closed the water flows though each radiators automatic bypass this keeps the pipe work warm (it wont freeze) when the outside temperature is well below -25c. MikeS |
|
#5
|
|||
|
|||
|
Hi
I'm a bit uncertain here whether the flow is top or bottom of the radiator, this shows bottom, other sources I have seen show top. Anyone know which it is in practice? "Dave Jones" wrote in message ... "BAHADIR" wrote in message om... Hi everyone, i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... http://www.diydata.com/planning/cent...g/pipework.htm |
|
#6
|
|||
|
|||
|
"Aidan" wrote in message m... (BAHADIR) wrote in message . com... or may be a link to a site about system... See also information about the diverter-tee/monoflo-tee system at the site below. This system isn't used in the UK, so far as I know. http://www.heatinghelp.com/heating_howcome3.cfm The diverter tee is similar to a spreader "Y" tee. We don't use diverter tees because a simple, cheap in-line restrictor can balance up a system. "Y" tees are horrendously expensive. |
|
#7
|
|||
|
|||
|
"Peter" wrote in message ... Hi I'm a bit uncertain here whether the flow is top or bottom of the radiator, this shows bottom, other sources I have seen show top. Anyone know which it is in practice? The flow entering at at the top is the best position, whether pumped or on gravity. The flow went into the top on gravity systems. No need on a pumped system. |
|
#8
|
|||
|
|||
|
"BAHADIR" wrote in message om... Hi everyone, i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... With a one pipe system the pump speed can't be too fast otherwise the water just bypasses the radiators and leaves them cold. They are used in large commercial systems where the loop pipe is oversized, so the loop is no too cool at the end. The are used in large system as running two 1.5" pipe in parallel is not practical and visually looks appalling. The designer will size the loop pipe and the radiators along the loop; the end rads will probably be much larger than those at the beginning of the loop. They were used in domestic systems in the 1950/60s to keep costs down when copper pipe was more expensive. Some would have a two pipe system on the ground floor and a one pipe on the first, where temp were lower and in those days the bedrooms were deemed to only have only background heat. When someone changed a pump and left it on the highest speed, the bedrooms went cold. I have seen a one pipe system ripped out to great expense because the pump was set too high, the "plumbers", not heating engineers, didn't know what was happening. A one pipe system with a condensing boiler is a no, no, as it keeps the return temp far too hot. A condenser needs the return pipe temp as low as possible. One pipe systems are difficult to balance the rads. In short a one pipe system is the worst case. A two pipe flow/return system is the best, as then you have far more control and balancing is far easier. An extra copper pipe is not expensive in a domestic system. |
|
#9
|
|||
|
|||
|
In article ,
"Peter" writes: "Dave Jones" wrote in message ... "BAHADIR" wrote in message om... Hi everyone, i have a final project about single pipe central heating systems, and heating a building with the system... i am studying mech. eng. and i need detailed information about this subject... it would be glad if there are anyone can help me... it may be your own knowledge or experience about the system or may be a link to a site about system... Thanks For everyone who will answer me..... http://www.diydata.com/planning/cent...g/pipework.htm Hi I'm a bit uncertain here whether the flow is top or bottom of the radiator, this shows bottom, other sources I have seen show top. Anyone know which it is in practice? I believe that picture and text is wrong. I think the author has got a single pipe system mixed up with a gravity system, and got one of his laws of physics upside down. In a single pipe circuit, water flows in the radiator because it has less resistance than the pipe underneath -- the radiator is like a big fat pipe in comparison, so a proportionally more water will go through the radiator. The outlet from each radiator is much better positioned at the bottom where it will take the cooler water out of the radiator. The inlet doesn't matter so much. I prefer it at the bottom -- the hot water will rise to the top inside the radiator anyway in the first one or two channels, but if the circulated water suddenly goes cold because another zone opens, then the cold circulating water will run across the bottom of the radiator leaving most of the radiator hot until the boiler catches up heating the additional volume of cold water. It also looks better in most cases with both inlet and outlet at the bottom. However, as the article points out, you will have different water temperatures in each radiator. If they're all in one room, it won't matter so much as the effect will cancel out in the room, but the heating they provide won't be even. If they are in different rooms, then you will have to take the different average temperatures into account which will result in undersizing the first radiator through to oversizing the last, or your room heating will be unbalanced. For balancing a single pipe circuit, it was done either by very accurately sizing the radiators and having a single flow restrictor for the whole circuit, or having one per radiator (and you will still need one for the whole circuit if you have other circuits running from the pump). -- Andrew Gabriel |
|
#10
|
|||
|
|||
|
"Andrew Gabriel" wrote in message ... but if the circulated water suddenly goes cold because another zone opens, then the cold circulating water will run across the bottom of the radiator leaving most of the radiator hot until the boiler catches up heating the additional volume of cold water. You are implying water only enterdd the rads via gravity. Not the case. The pump did fiorce water through the rads. If a sudden influx of cold water is present in teh system, then some of this will enter the radiator. For balancing a single pipe circuit, it was done either by very accurately sizing the radiators and having a single flow restrictor for the whole circuit, or having one per radiator (and you will still need one for the whole circuit if you have other circuits running from the pump). To save costs lockshield valves were omitted on the rads and one gate valve was inserted on the combined return at the boiler, to balance the whole one pipe loop. When having a two pipe on the ground and one on the upper floors a gate valve was always inserted. on the one pipe loop at the boiler. This way the pump could be at high speed and the balance gate valve gave the right flow for the one pipe circuit to operate. Most installers on changing boilers will not connect up to the one pipe system and will only do the job if they removed the one-pipe and replaced it with a two pipe. Some would make the customer sign a waver on the one-pipe loop, if it didn't work correctly after a boiler change. They would then cvharge for callbacks on the one pipe loop. Most of this was just pure ignorance, as a simple in-line restrictor would make it operate. In some cases they were not that stupid, they didn't want call backs as balancing was pig. |
|
#11
|
|||
|
|||
|
In article ,
"IMM" writes: You are implying water only enterdd the rads via gravity. Um, try reading what I actually wrote again. You seem to have misread or misunderstood it. -- Andrew Gabriel |
|
#12
|
|||
|
|||
|
"IMM" wrote in message ...
The diverter tee is similar to a spreader "Y" tee. We don't use diverter tees because a simple, cheap in-line restrictor can balance up a system. "Y" tees are horrendously expensive. No, I do not think that a diverter tee is similar to a spreader "Y" tee. A diverter tee is similar to a tee with an additional in-line restrictor. If you look at the link I posted, there is a diagram of one. I am not certain what you mean by a "spreader 'Y' tee" because I cannot find any other reference to this term. If you mean a Y-shaped tee, then a diverter tee is definitely not similar. |
|
#13
|
|||
|
|||
|
"Aidan" wrote in message m... "IMM" wrote in message ... The diverter tee is similar to a spreader "Y" tee. We don't use diverter tees because a simple, cheap in-line restrictor can balance up a system. "Y" tees are horrendously expensive. No, I do not think that a diverter tee is similar to a spreader "Y" tee. A diverter tee is similar to a tee with an additional in-line restrictor. If you look at the link I posted, there is a diagram of one. An in-line restrictor is adjustable. The diverter tee aims to do the same job a a spreader tee. A spreader T is a an odd shape and can't be made to look good on surface pipework in many situations, hence the diverter T. I am not certain what you mean by a "spreader 'Y' tee" because I cannot find any other reference to this term. If you mean a Y-shaped tee, then a diverter tee is definitely not similar. A Y shaped tee does the same job - deliver equal amounts of flow to both pipes. |
|
#14
|
|||
|
|||
|
"IMM" wrote in message ...
An in-line restrictor is adjustable. In which case I'd probably know it as a regulating valve. The Monoflo tees have fixed in-line restrictions causing a portion of the flow to go down the branch. A Y shaped tee does the same job - deliver equal amounts of flow to both pipes. No, only if the hydraulic resistance of the circuits is equal. |
|
#15
|
|||
|
|||
|
"IMM" wrote in message ...
With a one pipe system the pump speed can't be too fast otherwise the water just bypasses the radiators and leaves them cold. nope |
|
#16
|
|||
|
|||
|
"Aidan" wrote in message om... "IMM" wrote in message ... An in-line restrictor is adjustable. In which case I'd probably know it as a regulating valve. The Monoflo tees have fixed in-line restrictions causing a portion of the flow to go down the branch. A Y shaped tee does the same job - deliver equal amounts of flow to both pipes. No, only if the hydraulic resistance of the circuits is equal. Of which both types of tees do. |
|
#17
|
|||
|
|||
|
"N. Thornton" wrote in message om... "IMM" wrote in message ... With a one pipe system the pump speed can't be too fast otherwise the water just bypasses the radiators and leaves them cold. nope Yep it does. |
|
#18
|
|||
|
|||
|
|
|
#19
|
|||
|
|||
|
"IMM" wrote in message ...
A Y shaped tee does the same job - deliver equal amounts of flow to both pipes. "A Y shaped tee"? No, only if the hydraulic resistance of the circuits is equal. Of which both types of tees do. Agreed. Which makes your introduction of a "spreader Y-Tee" into the thread rather pointless. |
|
#20
|
|||
|
|||
|
"Aidan" wrote in message om... "IMM" wrote in message ... A Y shaped tee does the same job - deliver equal amounts of flow to both pipes. "A Y shaped tee"? Yep, shaped like a "Y". No, only if the hydraulic resistance of the circuits is equal. Of which both types of tees do. Agreed. Which makes your introduction of a "spreader Y-Tee" into the thread rather pointless. Going through the bits. The US diverter tee requires a pump with high head, which requires more power to operate it and more system noises. Best avoid. |
| Reply |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Forum | |||
| Feeble woman about central heating | UK diy | |||
| plastic air pipe | Woodworking | |||
| Hot Air Central Heating | UK diy | |||
| No central heating - HW only threewayvalve and tank therm | UK diy | |||
Linear Mode
