Myson Apollo Fanfare - Firing when switched off

[steve.turner]

All,

I have the above boiler, it has now started to fire up (and then stop) intermittently when all controls are off. I have put on a new programmer, this seemed to improve it for one day only (red herring?).

I can stop it running by switching the "economy" switch to "off" or "low" but then the boiler won't fire up when it is switched on.

Because of this it can't be left in the normal "off" state, it has to be switched off at the mains.

Any ideas?

Thanks

Steve

[Ed Sirett]

When the boiler operates is it getting the demand signal? I suspect that you may have something like a stuck microswitch on a zone valve.

Anyway the first thing is to find out is whether the boiler is getting a demand signal or not.