In message , obclare
writes
I have a problem with an Ariston a/23 combi boiler that has beaten
British gas and a handful of gas engineers.
The system fires up and immediately fires down again and fires up
again immediately and so on. Anybody any ideas?

Hard water area?

Is the heat exchanger scaled up?

Is there a blockage in the system

Is the pump working properly ?

I'm afraid, to properly diagnose this, more info is needed

is it fully firing up or just starting - still sparking?

Has this suddenly happened or has it been getting progressively worse?





Various bits have been
replaced but to no avail. Very occasionally the system works.

--
geoff