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False water line

This woke me up in the middle of the night:

We are replacing an OLD Weil McLain 44 series steam boiler (wet return) with a Smith 28-8. Obviously we need a feed water tank with a pump controller to hold excess system water. It has been about 15 years since I had to deal with this issue. The last boiler, instead of building a false water line column with multiple steam traps attached, we tee'd off of the equalizer above the Hartford loop, installed an F&T trap and ran the discharge back to the feed water tank. I can not remember where I learned this from. How do I size the steam traps to dump water fast enough and is there any advantage between types of traps, F&T vs Bucket?

Thank You for you help


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    edited November 2015
    Is this one-pipe or two?
    Remember that steam has expanded 1600 times from water, so there should be enough water capacity in any boiler to make enough steam to fill the system without the added complication of a pump and tank. Go with gravity return.
    I have a Peerless 211A, with 1.005,000 BTU, and 55 rads-all Gravity.
    If there is a problem later, you can always add a non-pumped reservoir tank, at waterline height to add some extra water.
    Make sure there are no existing returns which are close to the waterline height of the new boiler, and you won't need a false waterline either.
    This might be suitable for twinned boilers.--NBC
  • HeatJockey
    HeatJockey Member Posts: 37
    2 pipe. Big building. 2.5 mil btu input. approx 150 -200 rads. Plus pipe riser radiation. Big difference in water content between old boiler and new.
  • No matter how big the water volume of the old boiler was, the replacement boiler will have enough water capacity to fill the system with steam. Making sure the returns are able to return the condensate in a timely manner is the key. Only if the returns are remote and at a troublesome elevation would it be necessary to have tanks and pumps.
    Your client may be very grateful if you can remove another potential service problem in the future, as well as saving him a Grover Cleveland or two!!--NBC