Honeywell Thermostat CM901

borischelski

The settings are programmed to go on and off 3x per day.

However suddenly the heating had started coming on 24/7 within the originally preset target temperatures.

We have double checked and the system is on auto not manual overide.

Any ideas as to what may have suddenly gone wrong ?

wavelets

borischelski wrote: »

The settings are programmed to go on and off 3x per day.

However suddenly the heating had started coming on 24/7 within the originally preset target temperatures.

We have double checked and the system is on auto not manual overide.

Any ideas as to what may have suddenly gone wrong ?

The obvious answer is the thermostat has gone wrong!
(but I accept you've probably discounted that possibility, or at least looking for other possibilities. ))

One option to consider may be a stuck motorised valve. If that sticks, and the boiler is being called for heat to heat your domestic hot water, then the space heating could come on.

There are so many other possibilities too, so it may be you need to get a professional in to look at your own particular system.

MoneyMate

Sorry if its so obvious and you've checked but New batteries required ?