normal boiler pressure

[ssupercoolss]

i drained my boiler, put in all my tee's and valves in order to pipe the wood boiler in. before i drained the boiler i noticed the pressure was 10 lbs. i thought normal boiler pressure was 12, and maybe a few more pounds per floor. it was then i found out the valve for make up water has been shut. dont know why, dont know when. i have lived here since 2003. so i drained everything, plumbed everything in, and went to refill the boiler. open the valve, no water pressure. i notice on the side of the pressure regulator there is kind of another shut off valve on that device. open it up, water starts flowing. its leaking, but flowing. now i see why it was shut off. so, i have no idea what my system should be set at for pressure. when i refilled the boiler i took it up to about 18 lbs, and it still was letting more in. i knocked it back to about 15, and shut everything off. 2 story house, with the boiler in the basement, should my pressure be over 18 lbs? good news is no leaks on the plumbing i did.

 

[Eric Johnson]

Somewhere between 12 and 15 is what I usually keep mine at.

 

[sandman59]

On most automatic fill valves that is a manual "fast-fill" lever that allows the water to enter the system at a higher flow rate. When this lever is in the up position, the regulator is being bypassed to allow the system to be filled faster. I would replace the automatic fill valve and when you fill the system again, fill to 12 pounds, cold without the pump running. The system pressure will go higher when the pumps are running and the water is hot. Mine runs at about 21 psi hot.

 

[markpee]

Mine is just over 20 lbs hot - so far I'm not worried, but perhaps a bigger expansion tank will lower it? I don't think there's reason to worry about a system at 20psi.