My faithful Vaillant is now 10yrs old with a couple of parts changed over the years, divertor Vv and clock if my memory serves me. On return from my hols recently the heating came on for a short while and then went off. Burner lockout comes on after the 10s ignition time passes. My gas engineer pal has checked everything again and again having replaced the main switchboard to no avail. This was changed as the gas solenoid was only getting about 19Vdc and according to the book this should be 200Vdc. The flow charts also seemed to lead to change the main switchboard. Can anyone point us in the right direction?

John Murray, November 2006

I have now found out that it is not adviseable to change the main switchboard alone. The new board that was fitted has been blown, it should have been changed as routine with a new control board also as a pair. A new pair of boards have now been fitted and my boiler is now running as good as ever.

John Murray, December 2006

Check to see if you have gas at the supply side of the gas valve and also the burner side if the valve opens. It sounds like the valve is not opening and needs replacing.

John, November 2006