Hi all
I noticed something odd recently, and wondered if it might be due to thermo-siphoning, and if so - how I might stop it.
At the centre of my DHW & CH system is a thermal store.
The ground floor of the house is heated by water-based UFH.
One of the outlets from the store feeds the UFH manifold/mixer.
The outlet & return from the store, drop briefly, then rise about 4 metres upwards from the store, travel horizontally for 4-5 metres, and then fall 4 metres again down to the UFH manifold / mixer / pump assembly.
The UFH pump only runs when at least one of the UFH programmable room stats is calling for heat.
It's been pretty warm over the last few days, considerably warmer than the room stat target temps, so none of the zones have been calling for heat.
However - I noticed by accident that the UFH outlet pipe from the store is still hot. I went to check at the other end, and the pipework around the UFH mixer assembly is also pretty warm. The actual manifold itself is cool.
I turned off all the room stats, to be 100% sure the UFH pump isn't running, but the pipes remained warm.
They only cooled down when I turned off the isolation valves at the entry to the UFH pump/mixer assembly.
I guess the water must be circulating of it's own accord due to thermo-siphon effect ?
This must be wasting energy as there's a small but constant drain of heat from the store.
How can I solve this ?
Is it possible to wire in a valve somewhere that takes power from the UFH pump supply, so the valve only opens when the pump is running - and shuts at other times to prevent thermo-siphoning ?
Thanks for any advice !
Lee
I noticed something odd recently, and wondered if it might be due to thermo-siphoning, and if so - how I might stop it.
At the centre of my DHW & CH system is a thermal store.
The ground floor of the house is heated by water-based UFH.
One of the outlets from the store feeds the UFH manifold/mixer.
The outlet & return from the store, drop briefly, then rise about 4 metres upwards from the store, travel horizontally for 4-5 metres, and then fall 4 metres again down to the UFH manifold / mixer / pump assembly.
The UFH pump only runs when at least one of the UFH programmable room stats is calling for heat.
It's been pretty warm over the last few days, considerably warmer than the room stat target temps, so none of the zones have been calling for heat.
However - I noticed by accident that the UFH outlet pipe from the store is still hot. I went to check at the other end, and the pipework around the UFH mixer assembly is also pretty warm. The actual manifold itself is cool.
I turned off all the room stats, to be 100% sure the UFH pump isn't running, but the pipes remained warm.
They only cooled down when I turned off the isolation valves at the entry to the UFH pump/mixer assembly.
I guess the water must be circulating of it's own accord due to thermo-siphon effect ?
This must be wasting energy as there's a small but constant drain of heat from the store.
How can I solve this ?
Is it possible to wire in a valve somewhere that takes power from the UFH pump supply, so the valve only opens when the pump is running - and shuts at other times to prevent thermo-siphoning ?
Thanks for any advice !
Lee
