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steam pressure.

was on a service call today. burnham v series steam from 2008. most likely a "cut and slide" install. somethign strange that i moticed ( maybe it's not strange) is that there was no call for heat, only for domestic hw off the coil. the aquastat was set to 120. the boiler was stone cold before that because it has been off on safety since last night. when i got it running again i noticed the pressuretrol was a set at 5 psi. i turned it down to 2 with a subtractive differential of 1.5 Still might be too high, IDK, but at least it's better. now my question. after the boiler shut off on limit ( i assume the domestic aquastat, not the pressuretrol) the gauge was at 4psi. i can't rememeber the last time i saw a steam pressure gauge not read 0psi. there are 4 hoffman #75 main vents on the system right at the boiler. there are no wet returns and no hartford loop. dry returns come back to the boiler and straight in. the vents appear to be "newer but i can't guarantee that they are all working. they are in the run of a bullhead tee at the drop where the dry returns tie in like i so often see around here so maybe they are plugged shut. the tenant says that he has replaced many of the radiator vents but also that many of the radiators have been removed from the system and capped off. i'm sure the boiler is way too big for that house at this point without those connected. what are some other things that can cause the gauge to read pressure and what can i do to get this system running more efficiently next time i find myself there. i doubt the landlord will pay to repipe the near boiler stuff and hes not gonna buy a new boiler yet


  • BobC
    BobC Member Posts: 5,306
    Pressuretrols are not renowned for their accuracy, neither are 30 # pressure gauges - one of them could be lying to you. Did you check the pigtail to be sure it's not gunked up? Check the base of the pressuretrol to make sure the little hole in the base of it's brass fitting is clear.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jamie Hall
    Jamie Hall Member Posts: 18,903
    In addition to @BobC. -- vents. Whether those main vents are working or not, you almost certainly need some main venting on the mains themselves. You might also consider adding a 0 - 3 psi gauge somewhere -- you might be able to make a T and nipple and elbow configuration with the pressurestat for it (you have to keep the 0 to 30, working or not). Just to see what's really happening in terms of pressure.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Fred
    Fred Member Posts: 8,518
    As has been said, I'm beeting the pigtail the Pressuretrol is mounted on hasn't been taken off and cleaned out since the boiler was installed. That will prevent the Pressuretrol from seeing the actual pressure and allow the pressure to build well beyond the settings and pressure will build if the boiler is well over sized.