by ericmark »
Sun Jan 26, 2020 9:48 pm
I think the boiler will have a pressure releaf valve, and likely problem is fault expansion vessel, some times the pressure has simply leaked out but more likely the diagram has a hole in it, since inside the boiler person correcting has to be gas safe, and so as an electrician I have not worked on integral expansion vessels, only the external ones, which you could often keep things going by blowing up with a bike pump.