Underfloor Heating Problem

[GravyLaughing]

Hi,

We’ve recently installed a new single zone underfloor heating solution.

This worked ok for about a week and then stopped working. Doing a bit of investigation I found there seemed to be an issue around the mixing valve, if I turned up the thermostat hot water would start being pumped into the pipe below the pump and into the room (I put the this back again as I know this shouldn’t be set above 50 degrees).

As a workaround then I lowered the boiler temperature to <50 which enabled the UFH to function until the I could get the plumber back.

Plumber came back, drained some water out the system and did some “stuff” and it all started to work again, i.e. boiler turned back up to 75 degrees and UFH mixing valve thermostat at 50 degrees! He did actually confess though he didn’t know what he’d done to get it working though.

Anyway, 5 days later the issue has started again…..

Both pipes either side of the mixing value are hot, as is the pump itself. Again if I turn the thermostat up on mixing valve hot water starts being pumped around.

Hardware is a Grundfos single circuit constant supply temperature unit.

Our plumber doesn’t have a clue what the problem is so any help greatly appreciated!

Many thanks,
Brian.

 

[DeltaT2]

Certainly sounds like a faulty mixing valve or sensor Brian.
Fairly easy to check I'd think. I'd be a bit worried at the Plu
ber's lack of knowledge though!!! I hope he was cheap??

 

[GravyLaughing]

Thanks for the reply..... to answer your question, yes he was cheap, very infact, as we haven't paid him yet!

I'm going back to the supply to see what they say.

Cheers.