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The poor draft issue can sometimes be as simple as weather conditions. On real humid days I sometimes get calls for odors.

An older chimney on a humid day doesn't work too good

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  • Jason_15
    Jason_15 Member Posts: 124

    What causes a puffback on an oil fired unit? I've seen several references to them on here. I'm guessing a boiler or funace that becomes so clogged with soot that it starts venting into the house. Is this correct?
  • S Ebels
    S Ebels Member Posts: 2,322
    Could be

    Plugged up flues in the boiler, plugged chimney, delayed light off caused by a fouled nozzle or an electrode problem, anything that makes a mess of your draft, crud and buildup on the burner head.........the list goes on.
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,557

    In the most basic sense it's like a car back firing. When fuel is pumped into the furnace/boiler it should ignite instantly. If it doesn't there is a build up of fuel. When it does ignite it's basically an explosion, everthing ignites at once. The unit isn't designed to handle that much expanding vapor, so it pushes exhaust out of any place that it can, i.e. the cleanouts, the flue pipe or the smoke hood.

    Usually you'll just get a "bang" when it lights off. If it's bad enough it can push out soot which makes a mess in the mechanical room at best, or the whole house if it's really bad.
  • Weezbo
    Weezbo Member Posts: 6,232
    improper draft.

    likely the stack is also cool,and there is soot built up in the stack or chimney.
  • Leo
    Leo Member Posts: 767
    Puff Backs

    These can be caused by a number of reasons. First and foremost is lack of proper service. Second is improper adjustments such as not using combustion testing equipment. Third and very common are defective or worn parts of the ignition system. Often times after an annual service a nozzle has to be changed again. This little tiny part has a very tiny machined hole that controls oil flow and spray, one slight piece or junk and it can throw it off. I compare it to a medical operation. It is necessary but there is always a chance of infection.

  • mike c_5
    mike c_5 Member Posts: 4

    Your troubles are few electrodes out of adjustment, dirty nozzle or to much air and it is blowing the spark away from nozzle so you do not get proper ignition..
This discussion has been closed.