PK Boiler Headache
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  1. #1
    Join Date
    May 2007
    Location
    Michigan
    Posts
    309

    PK Boiler Headache

    &*&*)(&*(&
    &*(&*(&
    &*(*&

    OK thats out!!!
    anywho I have a PK boiler that goes into flame failure
    because of no rectification
    because the pilot tube and flame rect rod are carboned up - after a day of cleaning
    what is going on?
    is this flame really burning that rich?
    I am thinking I need to adjust the initial startup air requirement? LO FIRE SET SCREW -I COULD SCREAM!!!!

    I hate the older PK boilers - 10 years and that is it - why do these damn schools invest in them!!!!! CHEAP!!!!!!

  2. #2
    Join Date
    Sep 2006
    Location
    Alaska
    Posts
    458

    Flame Failure

    We had a few Burnham boilers that kept going into flame failure. After massive parts changing, a boiler specialist changed the transformers. Haven't had a problem since, anyway something to look into!!!!
    Law Of The Thermostat: He who has the thermostat wins!!!!!

  3. #3
    Join Date
    Mar 2008
    Location
    NY NY
    Posts
    181
    It would helpful to all if you posted the flue gas readings ( low fire/highfire )
    Local 30 New York, New York Operating Engineer

  4. #4
    Join Date
    Dec 2005
    Posts
    70
    The PK I have worked all have had a light off position with the damper as well has high fire and low fire position. Need to know the cabinet pressure???

    Then some combustion readings. Take care of 8 PK with damper set-up and 3 with VFD's

    cabinet has to be .4" w.c. on the ones with damper set up.

  5. #5
    Join Date
    Mar 2009
    Location
    VB
    Posts
    318

    Start from the begining

    What model PK?

    First you should check all cabinet and gas pressure, including pilot pressure. Second you should visually check the flame(after you clean the glass, of course) and see what the flame looks like during pilot and during ignition and low fire. If you have a hi/low/hi ,or a modulating PK it could be sooting during modulation. It sounds like you might have a N series if it is 10 years old, if so check all your linkage and jack arms and make sure they havent moved

    As far as cheap goes I have worked on every boiler out there for the last 22 years(not tooting any horns) and by far PK has the best package out there, and the most easy to work on in a cabinet style. If that boiler was never started up properly it will act like a piece of junk... IMO

  6. #6
    Join Date
    Jan 2006
    Posts
    25
    convert it to uv

  7. #7
    Join Date
    Mar 2009
    Location
    VB
    Posts
    318
    DITTO

  8. #8
    Join Date
    Jun 2004
    Location
    Milwaukee, WI
    Posts
    258
    Convert to UV, Verify the gas regulator is properly sized. I have found many regulators sized out of range.

    I have had many PK burners burn themselves with holes in them...
    Jeff F.
    www.vfdhelp.com
    VFD, HVAC Motors and Manufacture Assistance.

  9. #9
    The soot on these old girls comes from setting the pilot tube TOO close to the inside of the burner and pilot gas pressure that are WAY too high. There was an old service bulletin that specified 1/4" gap of the inside of the burner. The way early ones were set at 1/8" and would soot alot. Make sure the pilot tube is lined up in the middle of the second square down. Igniter can be 1/8" to 1/4" of the outer square portion of the same grid that the pilot tube is lined up on. I like flame rod gaps around 1" +/- 1/4" of the burner face. Pilot gas generally runs 1.5" to 2.5" see the factory fire test sticker on the back of the boiler for certain, a pilot turn down test is helpful to. I general go until it drops out and give the pilot regulator one turn in - this gets ya close.

    (Did you pull the burner and make sure there are no cracks? Response to earlier mention about holes - They generally start as a small seperation of the inner and outer burner screens and end up as big holes or cracks down the weld seem. The reason? - You loose the air gap on the face of the burner and the flame will burner on the face of the burner and wear the material out(heat), generally caused by lack of maintence(dirty burner / dirty heat exchanger-lack of draft) The other reason is if it is a 2 stage unit (low and High fire) low fire manifold gas pressures set too low will have the same effect. I keep my low fire manifold gas pressures at least .8"wc.)

    Combustion and cabinet air pressures will play a part in this pilot soot but ya got 2 get the pilot right first. Trust me they are not cheap, you get what you pay for. I have worked with the Factory service guys a few times and they are a great help and a wealth of info.
    BoilerBuck

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