Thanks for taking an interest and for your advice on refurb of valve.
Notes: diaphragm replaced in May 2007.
Rads heat up very fast when problem occurs.
After turning off hot water tap.
Central heating comes on (even though there is no demand for it).
This has happened 4 times.
First time Nov, I was confused by this. The only way to stop heating mode was to switch off power supply to boiler. On switching back on heating started up again but when I turned on and off hot water tap the fault went away.
Thinking the problem through I came to the conclusion that the diverter valve was probably sticking slightly open over the ch port and when water demanded it unstuck !!!
Second and third times Dec, it just righted itself after switching off and on power supply.
Last time Jan, I woke up to find the ch on (out of programmed time) and so decided to let the thing run. It ran as it normally does in this mode and then just stopped after 5-6 minutes.
I can only think that the valve must have become stuck after the last hot water demand the previous night and became unstuck due to temperature rise when it came on in the morning. This is why I think it is the valve that is causing the problem.
What do you think?
Do you have any tips or things to look out for on proposed refurb?
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