Ideal Response 100 intermittent issue

[mizziga]

Hi, In the last 2 weeks my boiler started to play funny (although it might have started earlier and I never noticed).
Unit is an IDEAL RESPONSE 100 combi boiler.
Whether through a programme or by manually switching the CH on, the boiler fires up and warms up the house. The "burner on" light stays lit and everything look as normal.
Pressure gradually rises from 1.3 and it reaches a max of 2.5, staying at that max level for the duration of the burner operation.
Then, after around 30 minutes from the initial ignition, the burner switches itself off ("burner on" light disappears), the pressure starts to slowly drop back and the radiators slowly lose their heat. The pump keeps on running.
I would expect this behaviour to be followed at some point by an automatic reignition of the boiler, but that does not happen.
I waited on a couple of occasions for up to 1 hour but the burner never switched itself on again.
I also tried in that interval to get hot water, but that does not reignite the boiler either, although i can hear the unit clicking, as if it was attempting to do something.
At this point, if I stop the programme or I manually switch the CH off, wait a few secs and try to either restart the CH or call for HW, the boiler comes back to life and works for say 20 minutes. Then it cuts off again.

I have noticed this behaviour most but not all of the times for the last 2/3 weeks
Radiators have been bled and actually become really hot, as normal.

Any ideas?
I'm thinking of calling Ideal service, but if there was a recognised behaviour with a simple fix to it I'd be happy to try that.

Thanks a lot!

 

[twgas]

Has the boiler been serviced recently, I suspect not!

 

[mizziga]

You are correct. No recent service

 

[twgas]

No need to say anymore then

 

[ChrisR]

Maybe it's the Single Malt doing it but I can't think of much that a service would adddress which would cause a fault like that.

Mizziga - if you remove the outer front panel, you'll see about 4 labelled red lights on the panel on the right. You'll see if it thinks it's trying to light. Might help.

What are you thnking, Mick?

 

[twgas]

build up of crud round the base of burner causing the spark to short to case and/or the sensing electrode dirty (same cause) similar problems found frequently on minimisers.