Hi I'm new to this site and am looking for some advice with my high pressure problem. I have an old Crane boiler that runs off gas and last weekend I needed to replace a leaking gasket above the circulator. Ever since that point the pressure is not stabilizing, and with sub zero temperatures in the Northeast I can't shut it down. I've replaced the valve above the diaphram expansion tank (tank bottom is cold, tank top is hot), I even relieved the tank of any air via the bleeder at the bottom. I also tried adjusting the pressure reducing valve by turning it clockwise after the pressure rose and it made no change. Usually, I'd expect the boiler to maintain no more than 15 psi (as indicated by a red needle), however every time it turns on it rises to above 25 psi and then I get concerned and shut it down. Please help.