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Inconsistent Water Level in Steam Boiler

Brad White
Brad White Member Posts: 2,398
If the boiler feed line connects at or near the point of level control, it may be forming a venturi and dropping the pressure hence level at the point of measurement.

The boiler level may be rising in fact, but the point of measurement, a sight glass I assume, has other ideas during the time the pump is running.

When you shut off the pump is the level restored?

I would feed the boiler about 1/3 the way up from the bottom, clearly below the water line but not so low that it stirs up any mud.
"If you do not know the answer, say, "I do not know the answer", and you will be correct!"

-Ernie White, my Dad


  • John Temporale
    John Temporale Member Posts: 5
    Water Level for Boiler

    Water level drops when condensate pump feeds water into the steam boiler. Check valves are holding, have been replaced. 140# of pressure on condensate pumps, 60# set point on boiler. Why is the water level dropping when the condensate pump turns on? Bigelow Boiler with an 84 year old #6 Fuel Oil Burner. Condensate pump runs constant, which is the design. Soleniod valve sends water to boiler. Level drops immediately when the solenoid valve opens up. 3 other boilers piped in series and do not experience this problem.
  • Steamhead (in transit)
    My first thought

    was that the colder condensate was causing the boiler water to shrink a bit. But you say the other three don't do that.

    What, if anything, is different about this boiler or its hookup?

    Has the water-side been cleaned recently?

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  • Make sure,

    the condensate pump will be able to "overcome" the steam pressure, try a gauge on the outlet side.

  • John Temporale
    John Temporale Member Posts: 5
    To Dave in response to inconsistant water level


    there is 140 lbs pressure on the condensate pump going to the boiler, and there are three other systems all tied together. I checked every source of outlet piping on the boiler, and this never happened before. The level on the glass drops like a rock when the valve opens to feed water into this boiler, only this boiler is experiencing this problem and as i said before, all the boilers are piped together. Could I be over firing the boiler when it starts to make up water and flashing the water to steam and dropping the gauge level? I know i have 140 lbs because i did change the gauge to make sure we had that 140 lbs, were only running 160 lbs of steam pressure. All check valves have been changed on the condensate makeup water line, I tried shutting the boiler header valve, I dropped the water level manualy and i didnt notice the level to flash in the gauge. Also, if i do let the boiler run on low fire it dosent seem to drop the gauge level as quick, thats why im wondering if i could be over firing it? That led to my second question, How do you adujust the oil pressure and viscosity on a number 6 ray oil burner, its model number is RCR8, its a model 550 oil burner with the old style visocsity valve, it has to be 80 years old, no one seems to know anything about it or be bothered on that note. I have a flow diagram that i made up on the system and can fax it to you.

    Thankyou for your time.

    -John Temporale.
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