myson boiler

[cattch08]

i have a problem with my MYSON 50B gas boiler.

the fault is it keeps shutting down and the pilot light goes out as well. it has a brand new gas valve fitted and new pilot burner assembly and a new thermal coupling. A lot of people said just buy a new boiler but if the 3 items above have been renewed it should work. if i just leave the pilot light on without programming thr heating/water it stays on 4 days once the heating or water comes on after a while sometimes hours the pilot light goes out.i thought the only thing that could shut down the boiler and pilot light was the loss of heat to the thermal coupling.i have confirmed that it is not blowing out die to wind or draught just wonder if the thermostat could shut it down

any ideas would be appreciated thanks al barron

 

[CH4]

The thermocouple connects to an electromagnet, within the primary gas valve, via a limit thermostat. If the boiler over heats, the limit stat opens and interrupts the current that holds the gas valve open.

So, the problem could be caused by a faulty limit stat or a bad lead/connection.

Alternatively, the boiler could actually be over heating. This could be caused by poor water circulation through the boiler or a faulty pump-overrun thermostat - intended to keep the pump running for a short while after the main burner goes off (to remove residual heat from the heat exchanger).