Central heating pump now constantly on

concerned123_2

Hi
My central heating pump is now suddenly on constantly even when the boiler is off. I assume it is something electrical, the pump is a Grundfos super selectric, about 7 years old. Any advice gladly appreciated.

gas4you

We need more info.

Make, model of boiler and what type of system you have.

Without this info I can only guess at a zone valve stuck on if you have any.

concerned123_2

Boiler is Potterton Suprima, not very savvy with what type of system, as far as I am aware it is just a standard system in a detached house around 7 years old. Thanks

gas4you

Your boiler controls the pump via its pcb, or should do in most cases.

It could be the infamous suprima pcb at fault, but you need to check that any motorised valve heads have not jammed on and are supplying 240VAC to the board first.

If you have a multimeter and feel competent and safe to check mains volatge, you need to check for 240VAC at the switched live terminal at the front of the boiler.

Mains kills, so be very careful. If any doubt get a pro in.

concerned123_2

Hi
Thanks for your reply again, much appreciated. The water has come on for a timed 1 hour and the pump has now switched itself off again.........
Does this help you if the fault does not occur again?