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Pilot problems

I recently had my gravity hot water boiler replaced with a Lennox Series PWB-6D, Mod.GWB8-175E. with circulator and intermittant pilot. Have had too many problems to detail here but the current stumper is that on a call for heat the pilot controller lights the pilot then turns on the main gas valve (Honeywell VR8304M-3152). When the main burners light the "whoosh" lifts the pilot flame off the pilot oriface far enough the break the pilot sensor connection. So the main gas valve shuts off. The pilot controller re-trys in 5 minutes. Most of the time the burner stays on but sometimes it doesn't. The company that installed the boiler doesn't know why this is happening but has tried lowering the pressure regulator setting (helped some) and plans to install a "pilot sheild". Any other ideas out there?


  • Dan Law
    Dan Law Member Posts: 59
    Pilot outages

    This is definitely one for a pro. I see this often, and usually (I emphasize usually -
    not always) it relates to excess primary air shutter settings. It's important to have a
    pro do this adjustment, because what your adjusting is the air fuel mixture to the
    main burners. Essentially what happens is that the initial ignition becomes a "hard
    light off". If you've observed this you can picture how the term applies. The rush
    of air into and around the burners pulls or “sucks” the pilot flame off it's burner.
    Cutting back the primary air can lessen this undesirable effect.

    would be to starve the burners of air in order to keep the pilot "on". Making this
    adjustment incorrectly can have disastrous effects. You could end up making large
    amounts of CO (carbon monoxide) and endangering your family's lives.

    Of course there are other things that can cause your symptoms, all of which
    concern proper combustion, light off and venting. The pilot outages are a tell tale
    symptom. PLEASE - Get a pro to look at it. If your installing contractor is stumped, they can
    get help from the manufactuer. Generally this type problem requires a visual,
    rather than phone assistance.
  • Brian Macdonald_3
    Brian Macdonald_3 Member Posts: 5
    pilot problem

    Thanks for the response. There is no air adjustment on the main burners - they are "factory set". Was not considering tinkering myself but many thanks for the warnings! Just looking for ideas for my contractor who seems to be somewhat at a loss. Will definately suggest contacting Lennox. Should have thaught of that first, as should the contractor, of course.
  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    That sounds like

    a Dunkirk boiler with Lennox nameplate...I recognize it by the model number. Dunkirk monitors this website, so I would repost this problem with thier name on it.

  • Mark A. Custis
    Mark A. Custis Member Posts: 247

    End the draft and screw up the ingnition. Try adding a draft dilutor above the breech of the heat X.

    Good day bad help.

    The draft in the flue could be picking the flame off the burner. Or the draft could be too much for the main burner.


    Help needs to be able to measure draft, manifold pressure (main gas valve pressure delivered to the orifaces at the venturis) Input pressure to the main gas valve, and hopefully be able to see electrons moving through wires (electical meter).

    Good luck,


    To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"
  • What is a draft diluter??

    and why would you add it?
  • peter desens
    peter desens Member Posts: 41
    Factory help

    All good suggestions, but w/such a new boiler I'm sure we can offer a factory fix. I would not hesitate contacting Lennox, but as the actual manufacturer of that boiler, we would be happy to assist.

    If you would like, please contact or have your installer contact our lead technicial for Dunkirk products, Mr. Bob Welch, at 1-877-386-5475.

    Peter Desens
    Technical Service Manager
    ECR International - Dunkirk Boilers
  • Peter you agree

    that adding a "draft diluter" is a good suggestion????
  • Boonierat
    Boonierat Member Posts: 58
    .............I'm still curious ???????????

    What's a draft diluter ????
    Stay loose; stay well,...................Nels
  • Ben_3
    Ben_3 Member Posts: 71

    A drft diluter? I think what he probably meant was a barometric damper installed on the flue pipe to help regulate the draft pressure in the boiler so if the draft is to strong in the chimney it will pull through the damper's weighted door which opens to take air from the boiler room instead of pulling through the boiler. Also do you have enough fresh air coming into the room for proper combustion. Did they put in a chimney liner to account for the upgrade in effiency, your chimney may be to big now! Also electronic igintion systems need to have a ground to operate correctly. All these should be checked by a proffesional!
  • peter desens
    peter desens Member Posts: 41

    I tend to like the most simplest solution to any problem.

    While pilots are pretty simple in nature, solving problems associated with them are not always as simple.

    I would start w/varifying proper gas pressure, incoming and manifold. Approx. 7.0 w/c incoming while boiler is off and 5.0 - 7.0 incoming , with 3.5 for manifold while boiler is running.

    If the pilot has not been replaced, it wouldn't be a bad idea to do so. Make sure to use the new compression fitting that comes w/the pilot.

    From ther, feel free to give us a call.

    Peter Desens

  • Why replace a pilot

    on a new boiler. Is there a factory recall on the pilots? By the way pilot gas is not regulated it is on line pressure. The pressure on the inlet side of the gas valve should not drop when gas is flowing if it is 7.0 " WC static then it should be 7.0" with a full load. If not then there is a gas pressure problem somewhere.

    I really feel that the problem with this guys system is one of adjustment, I hope there is some professional out there to help this poor homeowner.

    My humble opinion if you can not fix them then do not install them. Service and safety of the customer should be first priority.
  • Put the pressure back

    to the correct setting and do not let anyone put a pilot shield in unless it is factory authorized. As Dan Law instructed someone who is a pro needs to get involved with this system.

    I hesitate to give any more instructions than that as we a serving a homeowner here not another technician.
  • I do not agree on

    putting a "draft diluter" if it is a barometric on a design in warranty boiler with out factory authorization. I assume this boiler came with a draft hood probably set at a prescribed rise of the top of the boiler. To alter that with out factory involvement is asking for trouble. I know that kind of thing is promoted by many of the "combustion engineers" on here but I think on a new in warranty product the factory rep should be in the boiler room to authorize that kind of change. Not just my opinion that is the way I work. By the way if the factory can not fix it then I will drive them crazy until they do or authorize me to do it for them.
  • By the way when all is said and

    done the gas company could be mixing something with their gas due to the extreme cold weather and demand on their system. Some places still mix propane and that drives burners crazy.
  • Dan House
    Dan House Member Posts: 15
    Pilot Flame Problems

    I am glad to see so many ideas on this problem since I am the installer contractor that owns this problem. In reading the posts I have copied the phone number of the Dunkirk lead tech named Bob Welch and will call him ASAP. The gas pressure adjustment was little help and is set at 3.2 wc and the pilot orifice is a #77. I don't like the idea of messing with the draft. The current idea is a stainless steel shield the size of a business card that forms around three sides of the pilot. I got the shield off a Burkay boiler and have had good success in the past to keep the pilot flame on the sensor when nothing else worked. I still wonder why this occurs on this boiler and if the shield works who can argue with success. Mr. Macdonald and I have had an adventure during this installation and I hope most of all to get every bug worked out to our mutual satisfaction.
  • Brian Macdonald_3
    Brian Macdonald_3 Member Posts: 5
    Hi, Dan!

    I knew you were on the case and are committed to "getting it right", but you know me - I just like to understand things and this is an awesome forum for exchange of ideas and learning for everyone.

    To all reading out there, Mr. House and I have indeed had an adventure, but I would like to note for the record that Mr. House and his company have been responsive and professionally courteous through the whole affair. Never a hint of defensiveness about any problems that come up. As Mr. House noted in his post, they do take "ownership" of their problems. I am looking forward to getting this one resolved soon. Thanks all for the input!
  • tombig
    tombig Member Posts: 291

    Bless all the contractors who take "ownership" of their work. I'm sure you guys will knock heads, come up with a solution, and more than one person's headache will go away.

This discussion has been closed.