Heating staying on after programmer time ends

[markyp100]

Hi, we have had a new boiler system fitted for the last 18 months and lately the boiler has stayed on heating the rads after the programmer has gone off at 8.00pm. When it was fitted we had new pump, trv's, motorised valve and room stat fitted.

The boiler is a worc/bosch and was ok for the first year, but now randomly stays on after the programmer tells the boiler to end. When its on after the programmer time it stays burning and does not stop even if i turn the room stat down. Consequently my house gets very hot and even if the room stat is turned down the rads are red hot.

The only way to stop it is to turn off the electric to the boiler and tum back on again. I have had worc/bosch eng out and they have said the boiler is fine so have spoken to the electrician that wired it up and he said it maybe the motorised valve next to the tank that maybe faulty.

Does anybody know how i can check if it is the valve and what part of the valve i will need to replace, if not the whole unit ?

Thanks for your help.

Regards

Mark.

 

[adlplumbing]

is boiler located in the garage

 

[markyp100]

hi, no, the boiler is in the kitchen...i thought it might be the frost protection but bosch said it would never get that cold in my kitchen.

 

[adlplumbing]

is it a mechanical clock on the boiler

 

[markyp100]

no.... new digital one, the sparky replaced this first to see if it was faulty....made no difference.
regards
mark.

 

[adlplumbing]

whats room stat set to may be getting ghost singnal from that
but only guess

 

[markyp100]

the room stat is always set to 20, when its cold outside.

 

[adlplumbing]

turn it down and see if that makes any diffrence
other wise may need some else to actualy look