my boiler is leaking out of the overflow outside the water is also hot water.

paul docherty, February 2009

First check the pressure on your boiler it should read between 18-21 psi. If it is then it might be the pressure relief valve located at the top of the overflow pipe. It might need replacing, sometimes a little tap or opening and closing this valve might reseat itself. If the pressure is above 35 then the pressure regulator needs replacing.
Check the temp on the furnace (not the thermostat)this should be between 180 -240 degrees if higher it should be adjusted. If it cannot be ajusted then it needs repair call a tech.

xaviert20, March 2009

it may not be the expansion relief valve but the expansion vessel in or beside the boiler. This has to have air pressure of .5 bar. If no air pressure you can try pumping it up. If the pressure will not go up then it possibly has failed and needs to be replaced. [It has a rubber membrane inside which often fails]

gerard mc phillips, February 2009

your boiler pressure relif valve has failed, you need to replace it

Mr K, February 2009