Hi there, thanks for taking the time to read this. I've been trying to diagnose why my gas consumption is so high and been doing various measurements and tests.
With the UFH, my setup is about 10 room zones connected on two separate UF manifolds linked to one UF pump with a return blending valve from the LLH (picture) - i.e. there is no pump on the manifolds, just at the LLH - each room has an actuator opening each zone from the manifold. Total UF area around 160 sqm with UF pipes on average 150mm spacing (some 200 and some 100mm).
In the middle of the night I positioned a camera to see what calls for heat from the boiler at what time. For about two hours in the middle of the night, only the UF pump turned the boiler on, and I believe only 1 or 2 room zones (about 50-80sqm) would have called for heat (I had set the others back on temperature). I think in theory this should be a heat demand of 9kwh. However the gas consumption for that period shows the boiler was going on full 30kw gas burning per hour (I have ranged rated my 40kw boiler down to around 30kw).
My question is if the UF blending temp was turned down to 40/45 degrees, how should the boiler respond when it is set to a flow of 65 degrees? Will it just keep sending out 65 degrees, and because of the low return temp from the UF manifold into the LLH, the LLH will be sending back a low return temperature to the boiler, so the boiler keeps firing fully instead of modulating down to a lower temperature and consuming less gas?
If so, then would any setup with HW, UFH and radiators from one LLH always cause a boiler to fire too much - since the boiler is set to a higher to satisfy the HW but too high for the UFH and radiators maybe, but cannot modulate down because of the LLH distortion?
Thanks for your help... sorry this may be a rookie question!
With the UFH, my setup is about 10 room zones connected on two separate UF manifolds linked to one UF pump with a return blending valve from the LLH (picture) - i.e. there is no pump on the manifolds, just at the LLH - each room has an actuator opening each zone from the manifold. Total UF area around 160 sqm with UF pipes on average 150mm spacing (some 200 and some 100mm).
In the middle of the night I positioned a camera to see what calls for heat from the boiler at what time. For about two hours in the middle of the night, only the UF pump turned the boiler on, and I believe only 1 or 2 room zones (about 50-80sqm) would have called for heat (I had set the others back on temperature). I think in theory this should be a heat demand of 9kwh. However the gas consumption for that period shows the boiler was going on full 30kw gas burning per hour (I have ranged rated my 40kw boiler down to around 30kw).
My question is if the UF blending temp was turned down to 40/45 degrees, how should the boiler respond when it is set to a flow of 65 degrees? Will it just keep sending out 65 degrees, and because of the low return temp from the UF manifold into the LLH, the LLH will be sending back a low return temperature to the boiler, so the boiler keeps firing fully instead of modulating down to a lower temperature and consuming less gas?
If so, then would any setup with HW, UFH and radiators from one LLH always cause a boiler to fire too much - since the boiler is set to a higher to satisfy the HW but too high for the UFH and radiators maybe, but cannot modulate down because of the LLH distortion?
Thanks for your help... sorry this may be a rookie question!