Hot Water / Boiler Query

[aruck]

Morning all,
This may be quite vague and unhelpful but I'm hoping somebody can help me. We have a combi boiler. For a while we've only been able to get hot water when the central heating was turned on (ie. not when just switched to water only).

Recently we came back from holiday to find the house boiling hot (despite leaving the heating off). A few days later the boiler stopped all together. We called out a plumber who replaced what I think was called the overheating switch/valve (if my memory serves me!). This is apparently what had caused the heating to run permanently. This did get the boiler working again and fixed the problem of being able to switch between 'heating & water' and 'water only'. We also had hot water on demand without the heating on.

For no reason it has now decided to only give us hot water when the heating is running.

Does anyone have any idea what the problem could be? I appreciate the above is a bit of a ramble and may not be that helpful but feel free to ask me any questions and hopefully I will be able to make it clearer!

Thanks,
Adrian

[dirkgently]

Boiler make and model would help, but it sounds like a split in the diaphragm in the diverter valve.

[aruck]

It's a Worcester Bosch 240
Looks like this..

[Rickyy]

Agree with Dirk, if you remove the casing you should see a round brass fitting with a plastic rectangular housing. Between the two there should be a plastic plunger that should pop out and operate a microswitch when a hot tap is opened.

If it doesn't, the diaphragm has perished. Easy and cheap job.

[dirkgently]

aruck said:

It's a Worcester Bosch 240
Looks like this..

That model has a mechanical diverter valve, I think you need to get somebody Who can do the diagnostics.