Boiler wont stay fired up?

[keesh1967]

I have a Glowworm Economy Plus 40 boiler that I am having trouble keeping fired up. When I press the on button the boiler fires up and either clicks off after 2 seconds, sometimes stays on 5 mins or will run for the full hour.
It is the old style boiler with seperate immersion heater 12yrs old.

I have just changed the connector S202095 as it had snapped but that was just a matter of unscrewing it and replacing with the new one.

As I don't have the working instructions does anyone have any suggestions what the fault maybe?

thanks all

 

[John506]

gas valve?

 

[GasHed]

Partially blocked pilot injector causing a small pilot flame? Dodgy overheat stat or connections? Faulty thermocouple?

 

[Soggy_weetabix]

Partially blocked pilot injector causing a small pilot flame? Dodgy overheat stat or connections? Faulty thermocouple?

Check the Gas Valve does not let by to the pilot when the boiler shuts down.

Dave