boiler wont turn off

[Laburnum]

hi,

I have a glow worm 30 sxi system boiler,

the main circuit board was damaged so i have replaced recently all was fine until we have noticed that when the heating or water is meant to be off by the timer or manually the boiler keeps running.

any suggestions to this problem will be deeply appreciated

cheers

 

[nickso]

a shot in the dark here without any other system information but i had the exact same fault once when an installer had wired the boiler incorrectly to the controls. it made the boiler stay on permanently.

as you have had the pcb replaced perhaps a similar thing has occurred.

i cant remember my exact remedy but from memory it may have been something to do with the volt free inputs into the boiler.

could also be a faulty zone valve outwith the boiler though

 

[Laburnum]

thank you for your response

but not sure what the 'volt free inputs' are?

 

[ChrisR]

Was it ok before the pcb was replaced?

Boiler Thermostat connectionss usually need volt free contacts available at the thermostat. That means contacts with no voltages applied to them at the thermostat.
If you supply a mains live OR NEUTRAL up a thermostat wire in error, you may well either
1) break the pcb
2) hold the boiler on all the time

 

[Laburnum]

hi chris, thank you for your information

As im aware the boiler was fine before,

do you have any suggestions to try and cure this problem, or do you think i may be opening up a can of worms??

thanks again'