Worcester 9.24 Combi DHW Failure

[andychad]

After searching the forum for a while I'm beginning to home in on the causes of my problem but I'm looking for some confirmation that I'm not barking up completely the wrong tree. I am after all not a plumber.

Yesterday all was well with the boiler. Today, opening any tap on the hot water results in a flow of cold. If the heating is on (and that works fine) the boiler goes off. And whether or not the heating is on the demand light either stays lit or comes on but no flame in the boiler.

About 12 months ago a new diverter valve was fitted to the boiler, but I'm not sure that that is the problem this time mainly because the symptoms leading to the diverter valve replacement were gradual and this time the failure was sudden.

Could this be the flow valve micro switch? Could it be the diverter itself or am I miles out? If I'm off target any advice as to where I should be looking would be gratefully received.

Thanks in advance

Cheers

Andy

 

[ChrisR]

I think there are about 3 different models of these. CHeck the diverter is operating (visibly) when the tap is turned on. Check the switches(s) it pushes are operating.
Some models at least of these boilers had a relay, which one questioner had found had failed. If it has multiple contacts, that sounds quite likely in your case.
That questioner said that the relay was obsolete. That may or may not be entirely true, but secondhand parts are available (though hard to find), or relays can usually be replaced with one with the same spec .

 

[andychad]

Thanks ChrisR, I'll take a look at these and let you know

 

[andychad]

The push rod on the diverter valve is coming up quickly and is firm. It's reiggering the microswitch that is lighting the demand lights. I have replaced the microswitch but nothing changes.

I can't find a reference to a Relay in the manual. I wonder now if one of the pcb's has failed.

Any ideas?

Thanks


Andy