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Oil fired Burnham KV83

HenryT Member Posts: 128
hi everyone, I am posting for a buddy of mine who had an issue with his oil fired boiler.

He uses this boiler for hot water and steam heat. yesterday his site glass cracked which caused a flood in his basement.

my question is, what will cause the site glass to crack? does it have to do with age? or high pressure which may lead me to believe its the malfunction pressuretrol?

is it still safe to operate assuming he replaces the site glass?

Thanks in advnace.


  • BobC
    BobC Member Posts: 5,410
    Cheack and replace

    The pressure relief valve should go off a long time before a sight glass reaches it's limits and i suspect the noise of a boiler operating at that pressure would scare one silly. A sight glass is very tough but there is always a chance there was a defect in that one or perhaps it was over tightened.

    Remove the pressuretrol and make sure the pigtail is clean just to be safe, also make sure the ports that feed the sight glass are not blocked. Replace the sight glass and the gauge glass rubber washers and fire it up.

    I would monitor it to make sure the pressuretrol can shut it down if pressure does rise, you may have to raise the thermostat by a good bit on a mild day to build pressure if the system is well sized.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • HenryT
    HenryT Member Posts: 128

    How do one know if he has hot water heating or steam heating?

    Do all the controls work the same? a few things im trying to verify for my buddy:

    -what pressure do they operate on (same as steam,
  • ChrisJ
    ChrisJ Member Posts: 14,967
    edited February 2012
    Gauge glass

    If it has a gauge glass its steam.  Hot water boilers to my knowledge don't have or need one.

    I don't see that gauge glass breaking without a LOT of pressure.  In fact I beleive they are tested for 125PSI.  The pressure relief should pop at 15PSI and even if it didn't I have to think other things would blow before 125PSI.

    Perhaps whoever installed the gauge had the gauge cocks slightly crooked causing a strain on the glass which over time finally cracked it.  Maybe thermal shock or simply a defect in the glass?

    If it was mine, I would replace it and move on.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Jamie Hall
    Jamie Hall Member Posts: 21,568
    Controls and pressure

    The control for a hot water system are completely different from those for a steam system; there isn't much question here that since you mention a gauge glass (steam only) and a pressuretrol (steam only) you have steam.

    The maximum operating pressure for a residential steam system should be 2 psi; that should be the cutout pressure for the pressuretrol.  Anything over that will make the system malfunction and may create failures.  If for some reason you feel you have to raise the pressure over that, there are other things wrong with the system which need to be fixed.

    Hot water systems typically operate in the 10 to 20 psi range, depending on how tall the house is.  12 psi is a commonly cited figure.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • HenryT
    HenryT Member Posts: 128
    Last question

    He is operating at 12PSI, which is strange because thats how how water is operated.

    his boiler is full with water the entire time (not halfway) as indicated by the site glass.

    This is where its confusing.  If this is a hot water boiler, are they normally filled with water?  and as for the site glass, could it be a knucklehead installation?
  • ChrisJ
    ChrisJ Member Posts: 14,967

    Can you take pictures of the system for us?  Boiler, piping and even radiators?

    Are the radiators connected with one or two pipes? 
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • billtwocase
    billtwocase Member Posts: 2,385

    steam boiler converted to forced hot water? Is there a circulator on it? As others say, pics are worth a thousand words
  • Farrah
    Farrah Member Posts: 1
    Burnham Hydronics model kv83

    I have a Burnham Hydronics model kv83 with serial number 64696794 and I'm trying to replace the old thermostat can someone help me in getting the correct one from lowes store. I had purchased 2 already and both don't work. I don't have central air in my home. I only have heating and we use oil heating.

    Need HELP please!
  • ChrisJ
    ChrisJ Member Posts: 14,967

    Almost any thermostat should work for your system.

    I had my neighbor buy this thermostat and I recommend it to anyone who has steam and doesn't need a programmable thermostat.


    This is a slightly more expensive version that has a larger display than the standard version.

    Make sure you set it to 1 CPH for steam.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JStar
    JStar Member Posts: 2,752

    Why didn't they work? Did they do anything? How did you replace them? Did you turn the power off first?
This discussion has been closed.