I have a 24CDi boiler, which lately has been switching off when hot water is demanded. It switches off and back on about 3 times during a 5 minute shower for example. The heating side is running perfectly.
The boiler doesnt show any signs of a fault whatsoever other than turning itself off and on.
I recently had a new circuit board fitted, could this be the problem? Could the water pressure have been altered in any way so that the boiler thinks theres no demand? Any help much appreciated, thanks in advance, regards Jeff

Jeff, January 2009

If people have the same prob... it was the DIVERTER VALVE, all sorted now, cheers, Bun,Rup.

Jeff, February 2009

hi Jeff mine seems to be doing exactly the same thing. Ive been led to believe that it is either the diverter valve or the heat exchange. either way it can be expensive and fiddelly.

rup, January 2009

Next time it happens get someone to watch the lights on the boiler.

If the hot water demand light stays ON, but the burner light (the little flame) goes OFF, then the boiler's diverter valve is staying where it should be, but the boiler is shutting off the burner for some reason.

This could be because the temperature on the main g/w heat exchanger is too high, or it could be that the sensor detecting this is faulty.

If the hot water light goes OFF, then look to the diverter valve. If the valve has failed, it won't stay pushed out and will switch the boiler off. If the switch itself has failed, this can do the same thing.

Hope this helps

Bunslinger, January 2009