Axel

Thanks for the advice, I will follow it!

Hopefully the isolating valves won't leak - I think they were replaced at least once since new. If they do they look easy enough to get at.

More of an issue is if the isolating valves let by - that is hard to spot seeing that there are pressure drop issues already!

My client / friend has reported that the pressure has remained the same for 2 days now, meaning that there is some intermittency to the pressure loss. She has been having baths etc as usual and using the heating during the day as normal.

I suppose there could be a pipework leak that is heat sensitive and therefore intermittent, but I suspect the boiler the more likely fault.

Thanks again,

Axel

Also check if the brown wires on the ballast resistor are intact. this resistor will be located under the combustion chamber on the right hand side.

Put out the pilot light. Switch the boiler off so no one can use it.

With boiler cool (temperature on gauge will be around 20 degree C) pressurise boiler to high pressure (say 2.7 bar). Close off the two valves on two 22mm pipes on the left. Go for a walk and a cup of tea. Return couple of hours later to read the pressure on the facia mounted pressure gauge. If pressure has dropped, leak in the boiler. If pressure has not dropped, open one isolating valve that was closed off earlier. If pressure drops, then leak beyong isolating valves towards the rads.

Be warned that isolating valves can leak making above test useless. Good idea to replace said valves.

If you need any heads up, email. I work with these boilers all the time.

I have a contact with a few new end of line cylinders that they are trying to clear warehouse space of. Totally above board, but I do not know what they have left. I sent him an email so hopefully will hear back on Monday.