Worcester 240 - Domestic hot water

[Richard]

I have a Worcester 240 combi boiler. The central heating side of things works fine.

On the domestic hot water side of it, you have to turn a hot tap on fully to get the burner to light. Once lit, if you turn down the tap down slightly the burner goes out. The water also gets only slightly warm if the burner stays lit. I am aware that at high flow rates the domestic hot water will not get as hot as at lower rates. It is however not getting anywhere near as hot as it used to.

Does anyone know what is wrong and point me in the right direction?

Thanks in advance.

[Christian McArdle]

Do you live in a hard water area?

Christian.

[Ed Sirett]

You may have two faults hee one which has been creeping up for a long time and one whcih has suddenly come on.

The secondary heat exchanger has probably become choked with limescale and working much less well.

The new problem is that the water flow detector has become nearly broken (it is possible that it contains a diaphragm which has split) but jst works at high flow rates.

Repair the boiler then see if it the DHW heat exchanger needs replacement/descale.

[Richard]

...yes, I do. Richard