Weil-Mclain 78-80 series leaking

Bigj59

I have this Weil Mclain 78-80 series boiler, with the bad castings. Under operating conditions at least six of the sections are leaking (the other four sections have been previously replaced). The relief valves are set for 30 PSI, and were tested at 45 PSI which showed no leakage.

What would cause it to leak when operating but not under test.



Normal operating pressure is 20 PSI @ 180F

ScottSecor

Sometimes they leak when hot, sometimes when there cold.  Did you test both ways?   I've also seen them leak into the combustion chamber (not necessarily outside where the cabinet goes).

tim smith

So they are leaking between sections I would guess? Why is it you think you have bad sections? Sounds more like you need to replace section gasket sets. Just theorizing.
Tim

EBEBRATT-Ed

Unless the sections are actually cracked or corroded so the gaskets will not seal then the sections should be ok. Unless the pins are damaged from flue gas condensation