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Steam boiler over filling

I have a steam boiler that is over filling the boiler. Every week we pull out 25 gallons to get the water in the sight glass. It has a McDonald and Miller low water float that powers up a solenoid valve to refill the boiler. We don’t have many steam boilers around any more and all of our guys that knew them well have retired so please take it easy on me :). Any pointers would be appreciated. 

Comments

  • KC_Jones
    KC_Jones Member Posts: 4,820
    Does the boiler have an indirect water heater in it? If so the coil could have a leak adding water to the boiler.

    If that's not it, try closing the valve ahead of the auto feeder to isolate the supply from the boiler. If the overfill condition stops, then it's most likely a bad feeder and that either needs replaced or rebuilt.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    Weisinger
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,268
    There are three possibilities:

    1. If you have a tankless water heater coil in the boiler or an indirect water heater hooked to the boiler the coil could be leaking and allowing city water into the boiler. Disregard this if you don't have these.

    2. a manual shut off valve used to add water to the boiler is leaking by and filling the boiler

    3. If you have a automatic feeder that valve could be leaking water into the boiler or the control that operates the feeder could be defective causing the feeder to operate when it shouldn't
    Weisinger
  • Weisinger
    Weisinger Member Posts: 4
    No indirect water heater. By the feeder do you mean the solenoid valve? Or the McDonnell Miller? 
  • KC_Jones
    KC_Jones Member Posts: 4,820
    The solenoid valve, it could either be not closing, or have crud on the valve seat allowing the water to keep flowing.

    If the LWCO was feeding continuously, it would be reading a low water situation and should be keeping the boiler shut down.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    Weisinger
  • Jamie Hall
    Jamie Hall Member Posts: 17,049
    Weisinger said:

    No indirect water heater. By the feeder do you mean the solenoid valve? Or the McDonnell Miller? 

    Well, really both. Is it just a solenoid valve? Or is it a proper automatic feeder with controls for quantity fed and so on? If it's just a solenoid valve, it could very well be stuck partly open. The best test for that is to close the manual valve which should also be on the same line (if there isn't one protecting the valve... makes it difficult). Proper automatic feeders can stick open, too.

    However, don't overlook the possibility that the low water cutoff isn't operating properly. If it's the float type, the float can get sticky if it isn't flushed out regularly, and when activated keep the feeder open too long.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Weisinger
    Weisinger Member Posts: 4
    It is a cheap plastic solenoid. The kind you normally see on sprinkler lines. 
  • KC_Jones
    KC_Jones Member Posts: 4,820
    Weisinger said:

    It is a cheap plastic solenoid. The kind you normally see on sprinkler lines. 

    That would be my guess then. I'd strongly recommend something like this, the counter is also a valuable diagnostic tool on steam.

    https://hydrolevel.com/vxt-24-and-120-steam/
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    Weisinger
  • Weisinger
    Weisinger Member Posts: 4
    Thank all for the help! 
  • BobC
    BobC Member Posts: 5,228
    At this time of year water is pretty cold. If you feel the piping on both sides of a valve you can usually tell if there is flow through that valve. If both sdes are cold there is flow through that valve.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    Weisinger
  • veteransteamhvac
    veteransteamhvac Member Posts: 31
    KC_Jones said:

    Weisinger said:

    That would be my guess then. I'd strongly recommend something like this, the counter is also a valuable diagnostic tool on steam.

    Is there a guide somewhere that provides acceptable ranges for refilling 1 pipe systems? I have several VXT installed on client boilers and would like to have a better grip on it.
  • Jamie Hall
    Jamie Hall Member Posts: 17,049
    edited November 18

    KC_Jones said:

    Weisinger said:

    That would be my guess then. I'd strongly recommend something like this, the counter is also a valuable diagnostic tool on steam.

    Is there a guide somewhere that provides acceptable ranges for refilling 1 pipe systems? I have several VXT installed on client boilers and would like to have a better grip on it.
    Not really. The boiler manufacturers will sometimes quote as much as a gallon a day, but most of us kind of think that that is wildly excessive for a normal sized steam system. Most of the loss in a good steam system is from the vents, and that should be minimal, and figures we've seen seem to be in the less than a gallon a week to less than a gallon a month as pretty good.

    Anything much over a gallon a week and you should start looking for steam leaks, if not water leaks.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • KC_Jones
    KC_Jones Member Posts: 4,820
    I'm more conservative than @Jamie Hall , I say anything much more than a gallon a month and you should start looking for leaks, steam or water. Steam can be difficult since it's invisible.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15