Electric underfloor heating - not working

[Chasingsquirrels]

Background - we had a conservatory added about 11 years ago, concrete floor, underfloor heating wires in screed, tiles on top. Temperature sensor in the floor and this wall controller.

Has been turned off over the summer and I turned the power on a couple of days ago, reset the time and date etc. unit registered floor temperature and I turned the heating on - it only comes on if the floor temperature is lower than the set temperature. The unit "clicks" when the heating goes on or off, it clicked and the went blank, then came back on all unset again.

I have turned the power off and let it but it just keeps doing the same thing, it is as if it is shorting out and resetting when it tries to turn on.

I think it must he the control unit, I've taken it off (had a couple of small dead spiders inside and some cobwebs) and cleaned it up, it is just an electronic circuit board. Tried again but just keeps resetting.

I could buy a new control unit and fit it, which probably would be as cheap as getting someone out to tell me that's what i need.

But, could it be something else? And if it is, presumably that means having the floor up? In which case I probably wouldn't do anything about it atm anyway.

you could get an electrician in to test and fault find. Don't dig anything up before that.

Unless you have been drilling holes in the floor, the cables are unlikely to have gone wrong.

Thanks PJ. That's my thinking re wires in the floor, I just can't see how they would go wrong other than corrosion. I was going to get an electrician in but have found the control unit for £40 and I guess it's going to cost more than that to get someone out, and if it isn't the unit it us the something concealed (in the floor) in which case I think it would have to stay broken atm.

I just wondered if there was something obvious I'm missing.

The link I gave is actually the business which fitted the system originally, so I thought I'd call them on Monday and see what they say..
Thanks again.

Sounds like it is the thermostat.
We have had electric in two houses.
The floor coming on when under the temp is the tolerance level set.
You may need to reset the prog or put it on manual to over run the setting.
Still get an electrican to fit the replacement if you get one.
the cables will not corrode.

Thanks. There is nothing wrong with when / how it comes on re the temp levels, I was just giving background to how it works. The issue is that when the controller tries to activate the heating it seems to overload, blank the display and then reset itself as it it has shorted out.

I'm ordering a new controller unit and hopefully that will sort it.
Otherwise fingers crossed for another mild winter as we barely used it last year.

Hi, did you ever get to the bottom of this problem. I have the same controller and it’s doing exactly as you described?

Sounds like a fault in the controller, see here:

ensupport.getconnected.honeywell.com/s/article/Aube-TH132-thermostat-resets-itself-and-will-not-heat