Hi,

I have a Vaillant Boiler Turbo Max around 11 years old.

Now the boiler has stopped working as it should.

If you open the hot water tap, you get no hot water and the radiators start heating up, thats with the central heating off.

So, I called a plumber, he came around, quotes me £180 for a diverter valve, which he believed to be faulty. The price was abit much for me, so I called another engineer, who came around, checked the boilder and said the diverter valve was fine and that the Heat exchanger needed replacing.

So, he replaced the heat exchanger, and bingo, we have hot water not as hot as it used to be, before the boiler conked out, bearable, I would say.

BUT, the rads still heat up when the hot water is running.

I have told the engineer, he believes it may be a censor, but assured me that he will sort it out.

Can anybody shed some light on this?

If any additional info is required, please let me know.

Thanks.

Unhappy Boiler, April 2010

Plumber was correct - diverter valve

AndyP, April 2010

Your problem is clear when open hot tap the boiler fires and heating is coming on so it is dirverter valve not letting divert water to plate exchanger so water is not been heated up. Even though diaframe is functioning but it could be damaged plunger inside diverter valve letting water on heating side and not shuting of heating side when hot water tap is open

k, April 2010