So presumably that still worked as intended, heating the Maxipod from the stove, but stopped the reverse?
Thermo-syphon
- Thread starter Harry Bloomfield
- Start date
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CH is off, I am attempting to avoid using it.
Here - https://www.diynot.com/diy/threads/pipe-thermometers.597957/
They are not strictly pipe thermometers, just digital displays with a wired sensor, but cheaper and much more accurate than any clip on pipe thermometers. Just clip them against the pipe with a short piece of pipe insulation.
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OK thanks
anti gravity valves
How does an anti gravity valve help me save money on my central heating? What is an anti gravity valve? An anti gravity valve is a non return valve which works to prevent thermosiphoning. They ar…dolantethole.wordpress.com
Thanks, I will fit one next time I drain down. The thermosyphoning is in reverse to the normal flow direction with the pump running, so a valve should stop it completely.
[UPDATE] I have kept an eye on the flow and return temperatures for a few days, and managed to confirm that thermosyphoning does only take place when the last use of the boiler was to heat the HW cylinder.
Remember - I have a MOMO type 3-port, which stays put at the last setting it is used on, be it HW or CH, until there is a demand for the alternative.
When the 3-port 'parks' set for HW, flow temperature shows a few degrees cooler than return.
When the 3-port 'parks' set for CH, both temperatures will be almost the same. Both assuming boiler has not fired for a few hours.
Remember - I have a MOMO type 3-port, which stays put at the last setting it is used on, be it HW or CH, until there is a demand for the alternative.
When the 3-port 'parks' set for HW, flow temperature shows a few degrees cooler than return.
When the 3-port 'parks' set for CH, both temperatures will be almost the same. Both assuming boiler has not fired for a few hours.
Does MOMO have a mid-position? Just curious, I wouldn't want a mid-position valve. I've always had W-plan and the either/or valve (Honeywell V4044 or clone) is simpler, cheaper and more reliable. I never found waiting for the cylinder-stat to be satisfied was a problem, even with 3 young kids. And with weather compensation, needing PDHW, that's what you get with W-plan. With a mid-position valve, or S-plan, need to wire it to give PDHW.
BTW I got a pipe-stat, great little toy for £3-29!
It does and it did, before I fitted a new control system. My new control system does use the mid-position, my boiler now runs separate flow temperatures for HW versus CH, so it's one or the other, not both together.
OK thanks. Did you mean "My new control system does not use the mid-position"?
Sorry for the omitted word, yes.
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Thank you, I had never considered thermal syphon working in reverse, at moment DHW turned off, it is only turned on in the summer, as in winter every time the boiler fires up the DHW is heated anyway, in summer only turned on 3 times a week for ½ hour a time. The tank seems to stay hot enough for 2 days, to have hot water at taps. Running on a C Plan.
Have however had reverse flow with the CH and radiators getting hot when they should not, so fitted motorised valves to CH. Next summer I will check if tank warming boiler, but think unlikely.
Have however had reverse flow with the CH and radiators getting hot when they should not, so fitted motorised valves to CH. Next summer I will check if tank warming boiler, but think unlikely.
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