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High glass gauge level related to wrong pigtail positioning?

Vermonter Member Posts: 57
I've been tuning mine too. I'm a homeowner, but I'll try my best.

Your water level should be dead center in the sight glass when the boiler is stone cold. It sounds like you have a low water feeder that is adding too much water to the boiler. This could possibly be caused by the pigtail if it is causing the pressuretrol to malfunction. The pressuretrol should be set as low as possible (1.5lb cut-out 0.5lb cut-in.).

If the high water level isn't causing problems (wet steam, water hammer) then I wouldn't keep draining it and adding fresh water. Fresh water is pretty bad for a boiler because it will accelerate corrosion.


  • John_153
    John_153 Member Posts: 9
    High glass gauge level related to wrong pigtail positioning?

    Hi all,

    New steam homeowner here. What level should the glass gauge be, half full or more then half full? I keep draining water from the system and the boiler to get the glass gauge level down to about half full, but every few days the water level keeps going up to about within an inch of the top of the gauge glass. What level should the water be in the glass gauge?

    Also I noticed the the pigtail that connects the pressuretrol is in the wrong position. Referencing Dan's book it should be that the curved part of the pigtail faces front to back, instead I see through the circle when I'm looking straight at the pressuretrol. Not sure if this is causing the water within an inch of the top of the gauge glass or not, but I plan to correctly positioning the pigtail when the temperature reaches about 10 degrees here in Connecticut and I can shut down and work on it after the boiler is cooled.

    What level should the water be in the glass gauge and is the level related to a wrong pigtail position?

  • jim_72
    jim_72 Member Posts: 77

    John. Two things if your pressuretrol has a mercury switch (look inside) you need to reposition the pigtail so it's level, if not leave it as is.Second when your boiler is hot and making steam ,What is the level in the glass?IF the water level bottoms out during operation it will cause LOWC to add water.This can be caused among other things by a block or semi blockage in your return lines back to the boiler.They may need to be flushed clean.
    .The former homeowner may never had the system cleaned and maintained properly .Good Luck
  • John_153
    John_153 Member Posts: 9
    follow up - baffling differential dial!?

    Thanks! The water level never bottomed out, it always creeped more toward an inch from the top, never toward the bottom. So I took today off from work and here is what I did.

    I let the system cool down, drained the return pipe until the glass gauge was empty and no more water came out, then repositioned the pigtail so it's facing me, then went out and bought a new pressuretrol controller (the bottom of the old one looked pretty beat), installed the new one, then set its main scale as low as it would go to .5. When I fired up the boiler, the water level reached half, then when the new (PSI) gauge reaches about 1.5 PSI, the system shuts off.

    Thing is, what does the differential dial in the pressuretrol controller do? The literature says the differential dial (which goes from 1 to 5, so I put it on 1, the lowest) lets the pressure rise above the main scale cut-in point before the electric circuit breaks.

    Does this mean the differential dial allows the boiler to go up to 1.5 PSI then shut down? I've read we shouldn’t let our boilers go past 1 PSI, but doesn’t setting the pressuretrol controller and its differential dial to their lowest still allow for the unit to get up to 1.5 PSI?

  • Vermonter
    Vermonter Member Posts: 57

    You're exactly right that the minimum you can set the Pressuretrol is 0.5psi cut-in and 1.5psi cut-out. That's why I installed a Vaporstat on my system :)


    Your waterline should start in the middle when dead cold too :)
  • Is it a,

    Honeywell PA404A you purchased?, usually the (internal) differential 1-5 scale is "subtractive" of the main(cut-out)scale on the front face. I`m not too fond of these as a main operating control, the "lower-end" scale accuracy is just not there. I usually install a vaporstat as the operator, and use this as a backup safety.

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