Central heating comes on with hot water.

Jbartlam

Hi all. Having big problems with my Worcester heatslave 20/25 oil fired boiler.

The central heating comes on when the hot water does.

Tried replacing diverter valve, motherboard, thermostats, plus something else that slips my mind.

Each time problem seems to dissappear then returns a week or two later.

Also for separate reasons I think had to replace the valve outside the house that allows the oil in and the expansion vessel.

All in the last 6 months so just about had enough.

Jonesya

Well there shouldn't be any mystery to it, you should be able to find out what's going wrong each time by testing and fault finding.

Did you locate the fault for definite before you started changing parts?

jayyar66

Did you replace the complete diverter valve assembly or just the motorised head?

Jbartlam

Changed both head and valve

Jbartlam

Any suggestions on finding the fault I think we've tried everything now.

[Deleted User]

Ours has been like that for years. Its an old system so we w.on't be spending any money trying to fix it as long as we still have hot water when we want and heating when we want

southcoastrgi

blocked plate heat exchanger

Jakg

I have nothing to add to help, but I have the same boiler and the same problem.

I've changed the diverter head (no difference), and keep meaning to change the diverter valve next.