Underfloor Heating - Circulation pump Overheat

[PlumbingDetective]

Hi all, I’m trying to figure out why the temperature on my water is getting so high that it cuts off my circulation pump from running (greater than 60 degrees).
As expected, the thermostat triggers a notification to the control unit that then calls for hot water from the boiler (by opening a motorised valve) and at the same time triggers the actuator for the area where the thermostat is based.
I’ve tried changing the motorised valve in case this was stuck but doesn’t seem to have done much.
Do you have any further suggestions on what could be the cause and would warrant more investigation?
Thanks very much.

 

[cross thread]

White thermostat on the left ,is it operating

 

[PlumbingDetective]

I am not sure specifically about the thermostat - i would think that if the temp of the water gets above the value it’s set to then it should restrict the flow but given it’s set to 45 degrees and the water temp get to above 80 degrees, it’s not doing something. I’ll try reducing it and see if that has any effect.
Cheers for the pointer

 

[Madrab]

Get a decorators cap (like the one above it) and try adjusting it manually. Where is the pocket for the sensing vial, actually .... where is the actual vial placed?

 

[PlumbingDetective]

thanks for the reply - I’ll give that a go. There is a wire that goes from the thermostat and enters the circuit to the right or the temperature display gauge. I think it’s called a valve actuator with a remote sensor.
What confuses me is how I get the temperature down from the 80 degrees from the boiler to a suitable temperature for the underfloor heating. I believe it’s supposed to use the return to cool it down. The problem could be that the actuators take too long to open which means no release of cooler water…

 

[Johntheo5]

There's probably a safety overtemp sensor shutting the manifold pump down.

Havn't seen that type of control system, most are like this where a thermostatic mixing valve measures the mixed flow (required UFH flow temperature) temperature and mixes the hot boiler water with the "cold" UFH manifold return as required. Have you a link to that system?.

Where is the capillary sensor attached to the system?

 

[Johntheo5]

Uponor also state

• UFH Manifold Mixing Unit – The Mixing Unit is used to blend the water pumped from the heating source and the floor circuits, and helps to maintain the correct temperature for the entire system (OPTIONAL)

 

[Madrab]

enters the circuit to the right or the temperature display gauge

Ah ok, didn't see it when looking, spotted now.

What confuses me is how I get the temperature down from the 80 degrees from the boiler to a suitable temperature

You should crank your boiler down from 80Deg anyway TBH, get it down to 60Deg.