My Baxi 105e comes on with the timer, runs until the house is warm, but later if you go upstairs you can see it is starting and stopping, it fires up for a couple of seconds, then goes off for a couple and then fires up again, it carries on like this for ages, and then after a while goes off, but does it again later on.

There are no alarm lights on, just the normal lights. If I turn the heating temp dial down during this, it switches off. I have changed the temp sensor but it still does it. The DHW is working fine and the heating cuts out when the hot tap is run as it should.

Could it be the PCB or is there some valve or switch which could be causing this?

Hope someone can help, thanks.

MikeD, November 2006

Try replacing the gas valve modulator & lead - this part has a microchip in it which controls the gas going into the chamber and we had exactly the same experience which confused the heck out our engineer

The clicking noise is the valve opening and shutting I think

Think they cost about £40 plus fitting

Russell, December 2006