HW not CH to Bathroom radiator?
Can I use the HW in my bathroom radiator rather than the CH ?
I'd like warm towels all year round of is the only option to fit an electric rad ? -- Vass |
HW not CH to Bathroom radiator?
"Vass" wrote in message ... Can I use the HW in my bathroom radiator rather than the CH ? I'd like warm towels all year round of is the only option to fit an electric rad ? /\ or -- Vass |
HW not CH to Bathroom radiator?
In an earlier contribution to this discussion,
Vass wrote: "Vass" wrote in message ... Can I use the HW in my bathroom radiator rather than the CH ? I'd like warm towels all year round of is the only option to fit an electric rad ? /\ or You haven't told us enough your system to be able to give a proper answer. If you have an oldish gravity HW and pumped CH system, you could connect the bathroom radiator into the HW circuit and it would get hot whenever the boiler was running. If you have a more efficient fully pumped S-Plan or Y-Plan system - with zone valve(s) and a cylinder stat - putting the bathroom rad in the HW circuit is not very clever because it will only get hot when the HW is actually being heated - which isn't very often. In this case, you would do better to connect it after the pump but before the zone valves. That way, it would get hot whenever the boiler is running - either for HW or CH or both. -- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid. |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 10:42:55 -0000, "Vass"
wrote: Can I use the HW in my bathroom radiator rather than the CH ? I'd like warm towels all year round of is the only option to fit an electric rad ? Well you *could*. The problem would be that the radiator would corrode rather quickly. Apart from the electric suggestion, there are three ways to do this from the heating. 1) Use the bathroom radiator as a bypass for the boiler. If you look at your system, you may find a pipe between the flow and return from/to the boiler before the motorised valve(s) with something like a radiator lockshield valve on it. The purpose of this is so that if the CH and HW thermostats are satisfied and the boiler is in full burn, there is a path so that the pump can continue to run and dissipate the heat. You could take this out and replace it with the connections to the radiator. 2) If there is no bypass, then connect the radiator to the equivalent positions - i.e. after the pump but before the motorised valve(s). Either 1) or 2) will heat the bathroom radiator when either the CH or the HW comes on. It won't when neither is on. 3) Create a separate heating zone. This would need for the system to be changed to using an S plan configuration - one motorised valve for HW, one for existing CH and one for bathroom. (see Honeywell content site for info on this). This would allow completely separate control for the bathroom but would mean that a suitable thermostat for a bathroom would be needed. -- ..andy |
HW not CH to Bathroom radiator?
"Andy Hall" wrote in message ... 1) Use the bathroom radiator as a bypass for the boiler. If you look at your system, you may find a pipe between the flow and return from/to the boiler before the motorised valve(s) with something like a radiator lockshield valve on it. The purpose of this is so that if the CH and HW thermostats are satisfied and the boiler is in full burn, there is a path so that the pump can continue to run and dissipate the heat. This is how my towel rail is configured and I wish it wasn't! When it pumps through the towel when all other rads are off it makes quite a noise and stops me from sleeping at night. |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 11:56:55 -0000, "Mark Hewitt"
wrote: "Andy Hall" wrote in message .. . 1) Use the bathroom radiator as a bypass for the boiler. If you look at your system, you may find a pipe between the flow and return from/to the boiler before the motorised valve(s) with something like a radiator lockshield valve on it. The purpose of this is so that if the CH and HW thermostats are satisfied and the boiler is in full burn, there is a path so that the pump can continue to run and dissipate the heat. This is how my towel rail is configured and I wish it wasn't! When it pumps through the towel when all other rads are off it makes quite a noise and stops me from sleeping at night. You may be able to alleviate this by changing the pump to a Grundfos Alpha. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. -- ..andy |
HW not CH to Bathroom radiator?
In an earlier contribution to this discussion,
Andy Hall wrote: You may be able to alleviate this by changing the pump to a Grundfos Alpha. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? -- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid. |
HW not CH to Bathroom radiator?
Set Square wrote:
In an earlier contribution to this discussion, Andy Hall wrote: You may be able to alleviate this by changing the pump to a Grundfos Alpha. Or turning the existing pump down, as long as it still gives satisfactory circulation at a lower setting. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? Yes, I have heard that caveat (though I haven't come across that situation in practice, but then I've come across vanishingly few Alphas) |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 13:05:38 -0000, "Set Square"
wrote: In an earlier contribution to this discussion, Andy Hall wrote: You may be able to alleviate this by changing the pump to a Grundfos Alpha. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? There is a control to set the operating speed/power. In any case, though, there is not a need for a very great flow for bypass purposes - only enough to stop the water boiling if it were to otherwise stop flowing. Also, remember that this is more of an issue with cast iron boilers than those with low mass heat exchangers -- ..andy |
HW not CH to Bathroom radiator?
In an earlier contribution to this discussion,
John Stumbles wrote: You may be able to alleviate this by changing the pump to a Grundfos Alpha. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? Yes, I have heard that caveat (though I haven't come across that situation in practice, but then I've come across vanishingly few Alphas) Yes, I wonder how well they work with automatic by-pass valves. AIUI, an automatic by-pass only opens on the pressure rise resulting from low flow through the rads when all the TRVs are closed. If the Alpha backs off so that the pressure *doesn't* rise, the by-pass may not open and the boiler may overheat. -- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid. |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square"
wrote: In an earlier contribution to this discussion, John Stumbles wrote: You may be able to alleviate this by changing the pump to a Grundfos Alpha. These automatically back off their power as the flow resistance increases, which I suspect here is the reason for the noise. Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? Yes, I have heard that caveat (though I haven't come across that situation in practice, but then I've come across vanishingly few Alphas) Yes, I wonder how well they work with automatic by-pass valves. AIUI, an automatic by-pass only opens on the pressure rise resulting from low flow through the rads when all the TRVs are closed. If the Alpha backs off so that the pressure *doesn't* rise, the by-pass may not open and the boiler may overheat. You just make sure that the pump is set at a point that it always overcomes the ABV. -- ..andy |
HW not CH to Bathroom radiator?
In an earlier contribution to this discussion,
Andy Hall wrote: On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square" wrote: Yes, I wonder how well they work with automatic by-pass valves. AIUI, an automatic by-pass only opens on the pressure rise resulting from low flow through the rads when all the TRVs are closed. If the Alpha backs off so that the pressure *doesn't* rise, the by-pass may not open and the boiler may overheat. You just make sure that the pump is set at a point that it always overcomes the ABV. I probably need to educate myself about Alpha pumps. How many parameters can you change on them? As we known, a conventional pump operates on a curve (per speed setting) whose two ends are at max pressure/zero flow and max flow/zero pressure. In a heating system with TRVs, it would seem to be desirable to have a pump which provided a constant pressure regardless of flow. Then, when one or more TRVs closed, the flow through the remaining radiators would be unaffected. I presume that an Alpha goes some way - but not all the way - towards this, so that there is still *some* pressure rise to open the ABV when all the TRVs close? -- Cheers, Set Square ______ Please reply to newsgroup. Reply address is invalid. |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 17:23:31 -0000, "Set Square"
wrote: In an earlier contribution to this discussion, Andy Hall wrote: On Tue, 29 Nov 2005 15:00:38 -0000, "Set Square" wrote: Yes, I wonder how well they work with automatic by-pass valves. AIUI, an automatic by-pass only opens on the pressure rise resulting from low flow through the rads when all the TRVs are closed. If the Alpha backs off so that the pressure *doesn't* rise, the by-pass may not open and the boiler may overheat. You just make sure that the pump is set at a point that it always overcomes the ABV. I probably need to educate myself about Alpha pumps. How many parameters can you change on them? This one just has one knob to turn for the setting. If you look on their web site there is a procedure for setting the pump and ABVs. There is a more sophisticated one - UPE 15-60, which has a choice of two modes of automatic operation plus a head control. You can have a remote for it if you want.... As we known, a conventional pump operates on a curve (per speed setting) whose two ends are at max pressure/zero flow and max flow/zero pressure. In a heating system with TRVs, it would seem to be desirable to have a pump which provided a constant pressure regardless of flow. Then, when one or more TRVs closed, the flow through the remaining radiators would be unaffected. I presume that an Alpha goes some way - but not all the way - towards this, so that there is still *some* pressure rise to open the ABV when all the TRVs close? -- ..andy |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 11:34:24 +0000, Andy Hall wrote:
On Tue, 29 Nov 2005 10:42:55 -0000, "Vass" wrote: Can I use the HW in my bathroom radiator rather than the CH ? I'd like warm towels all year round of is the only option to fit an electric rad ? Well you *could*. The problem would be that the radiator would corrode rather quickly. If you put it through one of those ladder type towel warmers they are made of copper or brass I think. This idea is not new. Some of the 1930s mansion flats with central heating (in the very original and precise use of the term), put the DHW through the towel warmer. I discovered this when trying to change a washer on a basin tap. Only some of the flow to the bath & basin went through the towel warmer. The OP will also introduce a substantial delay to HW arriving at the taps. -- 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 |
HW not CH to Bathroom radiator?
On Tue, 29 Nov 2005 20:12:02 +0000, Ed Sirett
wrote: On Tue, 29 Nov 2005 11:34:24 +0000, Andy Hall wrote: On Tue, 29 Nov 2005 10:42:55 -0000, "Vass" wrote: Can I use the HW in my bathroom radiator rather than the CH ? I'd like warm towels all year round of is the only option to fit an electric rad ? Well you *could*. The problem would be that the radiator would corrode rather quickly. If you put it through one of those ladder type towel warmers they are made of copper or brass I think. This idea is not new. Some of the 1930s mansion flats with central heating (in the very original and precise use of the term), put the DHW through the towel warmer. I discovered this when trying to change a washer on a basin tap. Only some of the flow to the bath & basin went through the towel warmer. The OP will also introduce a substantial delay to HW arriving at the taps. Hmmm.... I can't imagine that this would be very good though. THe volume of water in the rail is not going to be large, and if it's just a basinful of water, the towels are not going to get very warm during ablutions. Running a bath would mean heat being supplied for a bit longer. I suppose another variant would be to put the towel warmer across the cylinder coil. At least that would heat the towel rail while the cylinder is recovering from delivering the bath water. -- ..andy |
HW not CH to Bathroom radiator?
The message
from Andy Hall contains these words: Is there any danger of them backing off so much that there's insufficient flow to cool the boiler during pump over-run conditions? There is a control to set the operating speed/power. In any case, though, there is not a need for a very great flow for bypass purposes - only enough to stop the water boiling if it were to otherwise stop flowing. Also, remember that this is more of an issue with cast iron boilers than those with low mass heat exchangers Boiling is not really an issue for me. Firing the overheat cutout is. I don't have an Alpha but I occasionally get the boiler isolated by the overheat stat which could be a problem if it ever happened when I was away from home in the depths of winter. However AFAICT it only happens when the boiler is heating the DHW shortly after the central heating has turned itself down for the night and then only so occasionally that I can't be bothered to bugger about with the flow rates though the heating coil and the automatic bypass. -- Roger Chapman |
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