PRESSURE BUILD UP IN HEATING SYSTEM

MikeyB

We had a new Weil-McLain CGa gas fired water boiler (forced hot water system) installed in April 2008. We are in the New England areas thus the unit did not operate much until the fall of 2008. We noticed that once the unit was set at a 15 to 19 psi operating level, we have been in a 4 to 6 week cycle in which the hot water pressure in the heating system slowly creeps up over time. The pressure builds up reaching as high as 30 psi. We have had no less than 6 service calls on this and everything around the boiler has been replaced (expansion tank, regulating valves, fill valves, backflow) at least once and we even had a separate system expansion tank installed on our main incoming water line a few weeks ago. Any theories on what might cause this are welcome. Thus far, our installer has tried about everything they can think of and Weil-McLain has only thus far taken guesses as to what might be causing the problem.

Mark Eatherton

Does your boiler do your DHW as well??

Might be a cross connection...

Got pictures?

ME

D107

Again someone's posting in my name & email

poster should delete forums.invision cookies.

roger john

Leaky tankless coil

roger john

Leaky tankless coil

Paul DeLaiarro_2

pressure build up

Is your system a radiator system or baseboard? I have had several of these calls like this, and there are some answers, I just need more info.....

Big Ed_4

Pressure

Sounds like from what you posted , not enough expansion tank...

Fire it up from a cold start and watch the pressure if the pressure increases install another or larger expansion tank.

heatguy

David where in the piping is your boiler feed located if it is on suction side of pump every time the pump starts there will be a pressure drop which will make the feeder add water .shut off supply to boiler and watch water pressure