Lock out on Glow worm boiler

[robbo33]

Ive got a Glow worm compact electronic condenser boiler (7 years old estimate), and it keeps locking out.

When I go to turn the hot tap on to use the hot water the boiler locks out after first first firing up and then heating for a few seconds.

However when I put the central heating on it fires up ok and warms the radiators alright with no problem.

The boiler engineer thought it was fan and replaced this but the same problem is still happening.

Any ideas, Why does the heating work ok, but when using the hot water the boiler locks out and fails?

 

[SafeGasInstall]

did boiler over heat or just went to lock out

 

[robbo33]

No it didnt overheat, it just went to lockout.

 

[BLOD]

I'd check the plate heat exchanger for blockage

 

[SafeGasInstall]

If it did not over heat then can not be blockage !!!

 

[robbo33]

I have noticed now that it it locking out when using the central heating, but it takes about 2 or 3 minutes before it locks out when using the central heating, but is much quicker to lock out when just using the hot water only at 5 to 20 seconds.

Would the pump need replacing?

 

[diamondgas]

robbo33, your most likely in need of a GSEngineers. Lockout could be a multitude of reasons, specially what you're describing.... It sounds most like it could be circulation problems which do mean pump and/or blockage. However you need someone there to see what is happening I'd say. Could just be a sensor fault end of the day! IMHO