I have a house over three floors with three heating zones. Ground floor is UFH and newish, the 1st and second floor are radiator zones.
Historically the radiators don't get very hot on the top floor, however I've just switched them on for the first time since last winter and they are the best I've ever known them to be!
When I was doing this test the downstairs UFH zone was off and its led me to conclude that when the UFH is on, not much heat is getting to the top floor.
This is my setup:
System boiler (EcoTec 637) with the main pump inside it - has more than enough power for the property. Temp set to 65 degrees. Pressure about 2.0 bar nominally.
The UFH has a separate pump connected to it's manifold and the two upstairs radiator zones have two port valves but no separate pump. The two upstairs zones use Nest and the UFH has its own separate stat system. The zone values and the stats all work fine.
The UFH manifold is very close to the boiler, as is the hot water cylinder. The two radiator zones are further away - first one at least 10m to first rad, second at least 15m from the boiler.
I have a theory that when the 65 degree water is hitting the mixer valve on the UFH that the majority of this is being sent back down the return to the boiler (as the UFH temp is set to 40 degrees), with the boiler correspondingly reducing down the output power and potentially pump flow speed as its thinks the water in the system is at a good temp?
Does that sound like a reasonable explanation, and if so is there anything I can do about it?
Historically the radiators don't get very hot on the top floor, however I've just switched them on for the first time since last winter and they are the best I've ever known them to be!
When I was doing this test the downstairs UFH zone was off and its led me to conclude that when the UFH is on, not much heat is getting to the top floor.
This is my setup:
System boiler (EcoTec 637) with the main pump inside it - has more than enough power for the property. Temp set to 65 degrees. Pressure about 2.0 bar nominally.
The UFH has a separate pump connected to it's manifold and the two upstairs radiator zones have two port valves but no separate pump. The two upstairs zones use Nest and the UFH has its own separate stat system. The zone values and the stats all work fine.
The UFH manifold is very close to the boiler, as is the hot water cylinder. The two radiator zones are further away - first one at least 10m to first rad, second at least 15m from the boiler.
I have a theory that when the 65 degree water is hitting the mixer valve on the UFH that the majority of this is being sent back down the return to the boiler (as the UFH temp is set to 40 degrees), with the boiler correspondingly reducing down the output power and potentially pump flow speed as its thinks the water in the system is at a good temp?
Does that sound like a reasonable explanation, and if so is there anything I can do about it?
