URGENT boiler kicks in and rads get very hot when clock is in off mode

[radblagger]

so we dont use the timer mode on the honeywell clock just put the heating on when we want and off when we dont manually

a few times recently but not every day the boiler starts up when we have turned it off the rads all get very hot far hotter than we ever set the temp too

all except for the rad in the hallway where the thermostat is that one stays stone cold

we have to switch the boiler off at the mains to stop it which seems to reset it till it does it again

i changed the timer/clock about 18 months ago because when you pressed the buttons the lcd went out the new one also does the same thing

any thoughts or suggestions please

merry christmas
david

ps for the 1st time 2 nights on the trot its come on by itself now

 

[Deleted member 120897]

Are we talking an s-plan, y-plan, combi boiler etc?

 

[radblagger]

Are we talking an s-plan, y-plan, combi boiler etc?

combi boiler........................ it does it when we turn the boiler off on the clock but not during use

 

[Deleted member 120897]

Could be a stuck diverter valve or (more likely) a timeswitch/clock issue - as in not turning off properly.

 

[radblagger]

Could be a stuck diverter valve or (more likely) a timeswitch/clock issue - as in not turning off properly.

so if the clock/timeswitch ive replaced it once without it making any difference

the 2 wires that connect on the back of the timeswitch where do they go? im presuming to the boiler i wondered if they were maybe defective or poor connection somewhere?

 

[Deleted member 120897]

I would think the time switch wire would go to the thermostat, then this to the boiler.