raden wrote in message ...
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?

Thanks for the reply.

It is a soft water area. Very unlikely the heat exchanger is scaled
up, as it is only 2-3 years old.

No blockage in the system since it has been known to work.

Pump seems ok, when the system works.

It seems to be more or less constant now, from an intermittent fault.
Apparently the gas engineer is now going to replace the heat
exchanger. Its a friend of mine, but it seems to be a case of just
trying things. I'm not a gas engineer, but I wondered if the
thermostat that tells the temperature of the heat exchanger could have
gone, so it thinks its hot and cuts off, but then there would have to
be another thermostat that tells it to fire up again. It does fully
fire up, as far as I can see. I don't know whether the spark stops.

I'm getting near to the stage to say get a brand new unit.



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