Boiler is acting strangely!

[Catmint]

Hi, our boiler is quite an old combi boiler, we had the pump replaced about 5 years ago.

Anyway, we currently have the heating switched off and the hot water on twice a day. But today we aren't getting any hot water at all, and all the radiators have come on and are red hot.

Can anyone diagnose what may have gone wrong, and prescribe a cure for our boiler? Or do we need a new one?

Thank you.

Sorry I got that wrong, it is a conventional boiler.

If you have a hot-water cylinder and it is not a combi, then the three-port valve has failed. Call your regular heating engineer who services it. It is a common and not very complicated job.

If he tells you that only the motor needs changing, tell him you would like him to leave you the brass valve that came with it, to save you buying another when it wears out. If it is over ten years olds, I would suggest changing the whole thing (it will be a more expensive job as it will require some draining and refilling) because IMO both halves will be wearing out so you may as well get it over with.

The valve is probably near the pump and probably looks like one of these

Honeywell and Drayton are good brands and often last 20 years or more.

Thank you Piglet John, I was hoping you'd turn up!

The hot water has inexplicably come back today, but clearly there's an issue that we need to get sorted.

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