Hi, I've installed a 2 zone kit that uses an RWC mixing valve, Thermomix with hot in, return to boiler and heat out to Ufh pump and return from floor manifold. From underfloor heating store but basically the same as a jug speedfit Ufh kit.
I thought I had a duff thermostat inside the reliance mixing valve but they supplied me a service kit and it's still not working.
The thermostat expands and contracts as it should, I tested it in a bowl of warm water, allowing the hot feed from the boiler to bypass the Ufh manifold but the inlet temp on the manifold is rising to basically as high as the boiler feed in, abou 65 degrees and the mixing valve control has no effect on any setting, I have just converted a y plan system to s plan with a separate zone for the Ufh and the return goes back close to the boiler return into the boiler. I've also fitted a bypass valve which you can hear opening when the boiler pump is on overrun and all zones have stopped calling for heat.
I'm really stumped, it's like the main system pump is overwhelming the mixing valve but it's running quietly on minimum setting.
I've no issues with the hot water or radiator zones or the boiler, and the Ufh manifold appears to be working fine and both loops heat ok, it's just there's no control of the temperature down to the 45 degrees needed for the floor.
I even tried restricting the flow to the valve by partially closing a full bore 22mm isolation valve I fitted in the supply to the Ufh zone but you have to almost shut it off completely to make any difference. There's no other parts in the mixing valve other than the spring and wax stat so nothing else I can see is wrong, I've tried the Ufh pump on different speeds, Ufh zones open or restricted, nothing makes any difference.
Any help would be great as I can't see anything wrong with the layout and components I have and I'm pulling my hair out with 50 degree water coming BACK OUT of the floor after nearly 50m of pipe run at the moment!!!
I thought I had a duff thermostat inside the reliance mixing valve but they supplied me a service kit and it's still not working.
The thermostat expands and contracts as it should, I tested it in a bowl of warm water, allowing the hot feed from the boiler to bypass the Ufh manifold but the inlet temp on the manifold is rising to basically as high as the boiler feed in, abou 65 degrees and the mixing valve control has no effect on any setting, I have just converted a y plan system to s plan with a separate zone for the Ufh and the return goes back close to the boiler return into the boiler. I've also fitted a bypass valve which you can hear opening when the boiler pump is on overrun and all zones have stopped calling for heat.
I'm really stumped, it's like the main system pump is overwhelming the mixing valve but it's running quietly on minimum setting.
I've no issues with the hot water or radiator zones or the boiler, and the Ufh manifold appears to be working fine and both loops heat ok, it's just there's no control of the temperature down to the 45 degrees needed for the floor.
I even tried restricting the flow to the valve by partially closing a full bore 22mm isolation valve I fitted in the supply to the Ufh zone but you have to almost shut it off completely to make any difference. There's no other parts in the mixing valve other than the spring and wax stat so nothing else I can see is wrong, I've tried the Ufh pump on different speeds, Ufh zones open or restricted, nothing makes any difference.
Any help would be great as I can't see anything wrong with the layout and components I have and I'm pulling my hair out with 50 degree water coming BACK OUT of the floor after nearly 50m of pipe run at the moment!!!