I have a Glow Worm Economy Plus 40B boiler. I have just had a new Thermocoupler fitted and for a few hours all was ok. Then the pilot light went out. I had to wait until next morning to re-ignite as after initially going out it would not ignite.
Next morning I turned thermo to zero then pushed in the Gas Valve and pressed the ignite switch and it ignited. I waited the 15-20 seconds then released the Gas Valve button and the pilot light went out. I can now ignite but as soon as I release the Gas Valve button the flame goes out.
Can anyone tell me why?

Andy, February 2011

Either the new thermocouple is faulty, or the gas valve power unit is faulty.
That is assuming that the pilot light is strong enough.

Carefree, February 2011