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SID BRAY Member Posts: 1
I have a Weil Mclain HE5, Series III boiler with cast iron
radiation and older 2 1/2" & 1 1/2" galvanized steel piping with a two pipe system. Also, I have in-floor radiant heat in a basement unfinished addition with its own pump, mixing valve and thermostat. I added four cast iron radiators in my basement a few years ago and piped it as a single pipe using 3/4" copper. My problem is that my boiler only heats to about 130 deg and that's on a cold day. There was no by-pass installed between the supply & return & Weil Mclain told me there should be one and that would bring the temperature up (the hi-limit switch is working okay). Also, the boiler circulator is on the return side and it handles the main level radiators and the four basement radiators. I can close off all the water flow to the basement and the boiler will not burn any hotter. Also I sized the radiators to see if my boiler was big enough to handle the larger water volume and it is. My other problem is that my basement radiators don't get any heat. Seems like the pipe is warm to the first radiator, but the radiator never heats up and the pipe leaving that first radiator never gets warm either--seems like an air lock although I never get air from the radiator coin vent or 90 deg elbow coin vents.
Anyone got any other ideas on the boiler temperature or the basement radiators??


  • Steamhead
    Steamhead Member Posts: 16,889
    How much radiation do you have in the house

    and what is the capacity ("Net IBR Rating") of the boiler?

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  • [Deleted User]
    My Weil

    Catalog says the HE-5 has a net rating of 94,800 btus. Sounds like you have a lot of radiation.

    The basement radiators will probably not work until you can figure how to divert some of the flow from the 2 pipe upstairs system. Maybe install a dedicated pump for the basement.

    Weil is correct. Their installation instructions mandate a bypass for low temperature ops, i.e. radiant or converted gravity systems. You are moving too much water through the boiler to get the temperature higher than 130. The HE-5 only holds 2.69 gallons.

    There should be someone in your area who can get you, or your contractor, the proper installation manual. The Manual Part # is 550-141-440/0385WP.

    Good luck.

  • Dana
    Dana Member Posts: 126

    Does the boiler shut down at 130 or does it just continually run on a call for heat and never actually get above 130.
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