Central Heating comes on of it's own accord

[Dominique]

Hello our central heating comes on of it's own accord. The timer controls are on timer but it is outside the time and the red 'on' indicator light is not illuninated.

1) Boiler make / model (gas or oil)
Gas boiler IDEAL Isar

2) What is / is not happening.
As above

3) Has ANYTHING else been done or changed recently.
Heat exchanger in November and Magnaclean

4) When did the problem start?
Not sure 2-3 weeks ago

5) When does it happen? eg, heating coming on or going off.
Early morning, middle of day nothing regular

6) Anything else you feel may be of relevance.
Some rads have individual thermostats others don't

Thanks for any feedback

 

[TonyW2]

Frost-stat fitted?

 

[Dominique]

TonyW2

What's that? And how would I know I have one? There is a thermostat in the hallway

 

[TonyW2]

Frost stat is like the hall thermostat, but acts in the "opposite" way, in that it fires up the c/h if the temperature drops down towards freezing. Acts as a safety device to overide the time controls if there is danger of freezing
Usually it is fitted if the boiler is in a cold place, such as outhouse or garage.
Obviously, this would only cause your symptons during very cold spells or if it has been set too high/ faulty.

 

[Dominique]

Our boiler is located in the bathroom of our house and it has been unseasonably mild for a week or more now.

We have the dial that is on the boiler for the central heating set on 2 (highest 6),

Where would a frost thermostat be located. I don't think we have on though. I would feel a bit silly if I hadn't noticed it after 10years

 

[TonyW2]

It would probably be out in garage, but from the position of boiler it is less likely that you even have one and if it is happenning when the weather is mild, I guess you can rule out the quick and obvious.

Sorry but the electrics and calls need checking to determine which component is playing up. Could be microswitch on valves sticking, but a systematic check is needed.
Are you OK with checking circuits at the wiring centre, etc?