URGENT Glow-worm hideaway boiler issues

[Colin ash]

I have a old glowworn hideaway boiler which has been working perfectly until a few days ago, had a engineer come out and change the thermocouple and it now ignites and stays lit.. that is until the central heating is turned on, stays on for around 10 mins and then completely cuts off. Reset everything as the manual says. Still does the same, however it stays on with no issues when just the hot water is on, pilot light stays lit. Anyone any ideas?

 

[Hkphooey]

I have EXACTLY, the same issue with a potterton boiler.
Works fine as hot water is heating as soon as my rads heating kicks in it goes flat the red light comes on, no rads working, I reset via button and everthing kicks back in and wirks as it should be until next time heat repeat reset.
Driving me crazy.

 

[Last Plumber]

Glow Worm:
Yes, it is a common problem - usually lack of a good service - and an easy fix for someone who is experienced with those boilers.
You need someone gas safe registered.

Potterton:
Your issue is different but should also be an easy fix but maybe with a part replacement.

 

[Hkphooey]

But clearly beyond the knowledge of a BG engineer then
I have a home service sub the boiler gets serviced every year and has only just been serviced, the issues have been bought up with them several times but after each visit the issue is still there.
Perhaps if you can let me know the well known secret I can pass it onto the BG engineer as BG seem to have not got the memo

 

[Vee]

Could be a weak pump causing a genuine overheat lockout due to lack of circulation.

 

[Hkphooey]

Could be a weak pump causing a genuine overheat lockout due to lack of circulation.

Yes the pumps BG are using to replace faulty ones are cheap £80

 

[Hkphooey]

Could be a weak pump causing a genuine overheat lockout due to lack of circulation.

Weird thing is if I use boost to put heating on at the same time it works ok with water on at same time