Why Would a preassure release on a boiler blow when not in use in the summer?

Question

and dont say because evil spirits have possed my house

Answer 1

I love the guesses you get on this subject. Your relief valve blows for one of two reasons. One is high temperature. We can rule this out. The other is high pressure. The pressure is continually building in your system because it is supposed to be 12 pounds on an idle system. When it reaches 30 pounds, the relief valve blows. This is caused by your pressure reducing valve leaking by, and should be replaced. This is normally a red B&G, or gold colored valve in the water supply to the boiler. There are other types of pressure reducing valves, but this is the most common. This can be a tricky replacement, and should be done by someone familiar with boilers. Hope this helps.

Answer 2

it is full of cold water and air then the air heats up due to temp change in temp when the boiler is shut down there is no place for the presser to go.  it dosent matter if the pressure goes from 50f to 90f  or from 120f to 160f you will see approx the same pressure change whith no place for the pressure to go

Answer 3

I am going to guess here. The expansion tank is waterlogged. Or the valve itself is bad.