BAXI Central heating problem

[dazontheweb]

I have a baxi solo 50 boiler. The external contols appear to be working correctly and Hot water is fine.
There appears to be a problem when using the boiler for central heating - the boiler goes completely dead. None of the lights on the boiler, such as boiler on light work. There is power at the S/L input. I replaced the Potentiometer but this changed nothing.
Do you think that I need to replace the PCB? I am loathed to spend £100 to replace this if it could be some thing else.
For some weeks the 3 position diverter valve by the tank has been making a loud buzzing noise. Could this cause the problem?

Darren

[KEVANS02]

You could be right about the 3 port diverter valve, there should be a lever on the valve which opens with a call for central heating. when the valve is closed it is in hotwater mode this is probably why the the boiler works on hot water and not heating. i whould guess that the synchron motor inside the valve head has burnt out and need replacing , this will cost you about 10 -15 pound to buy

hope this helps, kev