Hi everyone,
I’m new to posting on here but have often turned to this forum for helpful advice over the years. Now I’m hoping for some troubleshooting help from the underfloor heating and biomass experts here!
System Setup:
UFH is supplied directly from a thermal store via an inset woodburning stove with back boiler.
Current Status (which all should mean flow is happening):
Despite all of the above, there is no flow through the open UFH loops when the blending valve is set to 30-35°C ish... or at any temperature say below about 50°C.
The puzzling part:
If I increase the blending valve temperature to 50–60°C, then flow instantly resumes at the desired rates (visible on the flow meters) - but at that temperature the water is far too hot for UFH.
My Understanding & Questions:
My understanding is that the blending valve should mix water to the set temperature (e.g., 30°C) and supply it to the manifold, where the pump then circulates it through the open loops at the set flow rates for each loop.
1. Is my understanding correct? Should I be able to set the mixing temperature on the valve without it impacting the flow rate?
2. What could be wrong? The valve seems to be directly restricting flow at lower temperatures, and at higher temperature letting lots of flow into the loops. Could the valve itself be faulty, or is there another component (like the pump or system pressure) that might be interacting with it?
Any guidance or troubleshooting steps would be greatly appreciated!
I’m new to posting on here but have often turned to this forum for helpful advice over the years. Now I’m hoping for some troubleshooting help from the underfloor heating and biomass experts here!
System Setup:
UFH is supplied directly from a thermal store via an inset woodburning stove with back boiler.
Current Status (which all should mean flow is happening):
- Blending valve set to 30°C
- Wall thermostats calling for heat
- Manifold actuators open, pins free
- Central heating and manifold pumps running
- UFH zone control open
Despite all of the above, there is no flow through the open UFH loops when the blending valve is set to 30-35°C ish... or at any temperature say below about 50°C.
The puzzling part:
If I increase the blending valve temperature to 50–60°C, then flow instantly resumes at the desired rates (visible on the flow meters) - but at that temperature the water is far too hot for UFH.
My Understanding & Questions:
My understanding is that the blending valve should mix water to the set temperature (e.g., 30°C) and supply it to the manifold, where the pump then circulates it through the open loops at the set flow rates for each loop.
1. Is my understanding correct? Should I be able to set the mixing temperature on the valve without it impacting the flow rate?
2. What could be wrong? The valve seems to be directly restricting flow at lower temperatures, and at higher temperature letting lots of flow into the loops. Could the valve itself be faulty, or is there another component (like the pump or system pressure) that might be interacting with it?
Any guidance or troubleshooting steps would be greatly appreciated!
