Daz G wrote:

My room thermostat does not appear to be working , i.e it is not cutting
off the heating when it reaches its temperature, therefore the heating
is just constantly belting out heat, I have took the casing off and
cleaned it out in case it was the connection but no difference. Can
anyone advise what else I should do or do you think it needs replacing?
Cheers

Ah, diybanter. If your stat is managing to switch the 240v, its
something else, most likely the 2 or 3 port valve. If your stat doesnt
switch the 240v, the stat aint right.

Stats have 2 3 or 4 wires.

2: live, switched live
3: as above plus neutral to power the compensation resistor
4: as above plus earth

If you dont know how to do it safely, dont, as it will be live while
testing.

If its a bimetal stat, as it probably is, and it isnt switching, stuck
contacts can be wiggled apart and the surfaces smoothed with a rats
tail file or very fine sandpaper. Obviously dont do this with power
connected to it.

Doing this could knock the alignment off, so afterwards slowly turn it
till it clicks, to see if air temp matches dial temp. If not, adjust.


NT