calling for c/h or h/w boiler fires for 10 seconds and goes to lockout reset it and it just does the same could it be the gas valve or pcb board

john brown, May 2005

Update to Intermittent Hot Water Only.
Please note since I posted the original last year, I should point out that the other cause of this problem is the flow meter.
sometimes tapping this gently can start the boiler up for hot water. this is located on the right hand side and bottom of the boiler.

Also, a tip I was given for checking if the thermistors are faulty is to swap the two thermistors over. There is one for hot water and one heating. If you change them over the hot water problem should clear and the heating should have the problem. Then it is advisable to change both of the thermistors.

I hope this helps

Be sure to drain the water from the boiler and disconnect the electricity supply before attempting a repair.

Clive, May 2006

you may also have a damaged or blocked flue venturi.

andy, January 2006

The answers are also elsewhere on this site.
But briefly the problems can be temperature sensors (2) eg thermistors, or sometimes the hot water flow temperate sensor (two minute job). Part available from plumb centre - part number 800320 (E23-839).

If you are not technically minded or used to plumbing get professional help.

Clive

Clive, August 2005