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Low water cutoff shutting down boiler before house gets warm

Mike K_9
Mike K_9 Member Posts: 2
I just had a new steam boiler installed. Before the boiler fires, the water fills approx 75 percent of the sight glass, but after the boiler has been firing awhile, the water level in the sightglass drops right out of sight, and the boiler shuts off. I also hear a water gurgling sound echoing through the pipes when I listen near the rad air vents. I have significant increased the amount of venting (main vents and rad vents), but even so the rads farther away from the boiler are not getting hot. The pressuretrol is set at 6-8 psi. I know the recommendation is to turn down the pressuretrol, but would that be causing the problem? Any thoughts?


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    pressure too high?

    yes set it for ounces 2-8.[with a vaporstat and gaugestore.com]
    check your water quality--could need skimming
    also compare your near boiler piping [supply and return] with the installation manual for your boiler.if there are any differences in the "as installed" from mfg. instructions post some pix here so all can advise.
    get a copy of dans steam book fro this site and become more informed about steam!
    good luck,i've been there done that--nbc
  • Mike Kehoe_4
    Mike Kehoe_4 Member Posts: 4

    I don't think the near boiler piping is the issue; it looks good. The water is very dirty right now (looks like strong tea) and the installer is not done with the skimming process. I'm wondering if that may be why he has the pressuretrol set so high for now. But, would the higher pressuretrol setting be causing really wet steam/water to go up into the system? I know that sometimes it is recommended to oversize the boiler, because today's boilers use less water, but this new boiler is only slightly smaller than the old one, and I never had this problem with the old one.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Commisioning a new Steamer

    Commissioning a new steam boiler takes time and should be done per the manufacturer's instructions, or Dan Holohan's articles found in his book, "The Lost Art of Steam Heating", or archived on this site.

    The new boiler acts like a scrub brush to the old piping and will bring back huge amounts of sediment from the old system unless treated with TSP or specialized boiler additive and flushed thoroughly. Blow down the LW cutoff daily for the first few weeks and monthly during heating season.

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