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Low Pressure Weil McClain

Gage read 0 pressuretrol looks to be at 0. What can I safely try and run the system at? Can I bump cut in up slightly? Install a lower pressure gage? Cannot seem to get adequate heat on second story.  Been fiddling with vents and traps but cannot seem to get heat steadily on far reaching rads. Is the system just too low on pressure? 


  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    Low pressure is good on steam... but if your pressuretrol is at all accurate, you're set too high -- too low. It looks in the picture as though the indicator is seta round 2 -- it should be just barely above 0.5.

    The 0 to 30 psi gauge will likely not show you anything at all. They don't. They're there to keep the insurance companies and building inspectors happy.

    Are your radiators connected with one pipe at one end, and a vent at the other, or with a pipe at one end and another pipe likely with a trap at the other? You mention both vents and traps, which has me a bit confused. Regardless, are there any main vents on the steam mains?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 15,658
    Vents and traps?
    Is this a 2 pipe system?

    What vents are you using? What size radiators?
    Can we have an overall picture of the boiler and its piping, as well as some of the radiators and the vents you're using?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • neilc
    neilc Member Posts: 2,700

    I'm assuming the gage and Ptrol are mounted together, after the pigtail,
    have you checked and cleaned the pigtail, and know it to be clear back to the boiler?
    can you easily blow thru the pigtail back into the boiler?
    (maybe you're overpressured and sealed your vents shut? )
    known to beat dead horses