My problem has switched since I repressured my Vaillant Turbomax 824 boiler. The central heating was not working and the pressure was at 0.8. I followed instructions to repressurise and slightly overfilled (2.5). For most of the evening I had heating and hot water. Then I noticed the heating had remained on, even though the timer should have turned it off. In addition, I can no longer get hot water -- if I turn the boiler on, regardless of setting, temperature etc, the central heating goes on full blast and no hot water is produced.

Fran, October 2006

This a divertor valve problem and I think you probably have the warmstart feature on (green light flashing all the time). Turn the hot water temp dial all the way to min temp and the light will go out. Then turn it to the desired temp. Your heating will work when you want it to but your hot water will still not operate. The divertor valve needs changing to get your hot water back, but for the time being, your heating wont be on all the time.

John, November 2006

Dump the excess pressure by opening a bleed screw on one of your radiators. It may take some time and a fair bit of water will come out. The excess pressure may be preventing the divertor valve from operating. 2.5 bar is not normally a problem for most boilers.

kenneth, October 2006