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Can black soot on air filter, in furnace & returns in house be caused by a fixable leak?

fred9 Member Posts: 29
I'm homeowner with 22 year old Heil oil burning hot air furnace. My oil company has told me it's from a cracked heat exchanger and that I need a new furnace. Their salesman came out and is working up quotes. He did not look inside furnace. I called second company and their salesman did remove the back panel but could not see a crack in heat exchanger. Should get someone to look closer to find the leak/cause of black soot? That is , could it be from a malfunction that's fixable? It's now AC season and the filter after three weeks is almost pure white.



  • billtwocase
    billtwocase Member Posts: 2,385
    Have it checked thoroughly. Could also be from burning candles, coal, or wood in the house
  • David Sutton_6
    David Sutton_6 Member Posts: 1,079
    Also check clean out covers for leakage
  • Kakashi
    Kakashi Member Posts: 88
    You're not going to see some cracks. You may want to try two brand new clean out covers and gaskets to see if it helps.

    The guy who trained me used to throw cinnamon sticks and peppermint candy into the fire chamber and see if the customer noticed anything.
    Anyone with a combustion efficiency kit could have an idea if you really have a crack or not due to the fire changing when the blower comes on. It's not always the case but, at 22 years old...
  • burnerman_2
    burnerman_2 Member Posts: 297
    well one time I had a newer furnace with black filters .. turned out the chimney was full so smoke had to go some where... be sure it is Open.....
  • rwhtg
    rwhtg Member Posts: 34
    Has the house been remodeled? The house could be going negative while the furnace is running. If you have a return in the CAZ ( combustion appliance zone ) you could be pulling from the draft regulator into the duct system. You should have a BPI certified energy auditing company do a blower door and CAZ test. BPI.org should help you find somebody near you.
    Skilled labor isn’t cheap, cheap labor isn’t skilled.
  • spoon22
    spoon22 Member Posts: 32
    Most likely with a 22 year old Heil it is time for a new one. If you take the 2 sheet metal covers off to gain access to where clean outs are and fire the burner look down inside jacket if you see light on the left or right side the heat exchanger is cracked. Did the oil company do a draft test or use an analyzer either will show a cracked heat exchanger.
  • fred9
    fred9 Member Posts: 29
    Thank you for all the input.Not remodeled and no candles, coal or wood in 22 years.
  • fred9
    fred9 Member Posts: 29
    No cracked heat exchanger! I finally took your advice and had my oil furnace checked closely. (Don't ask me why I was too dumb to not do it months ago.) After the 3rd hvac "salesman" wondered if I really had a bad heat exchanger I requested his company come out and do a closer visual inspection and a combustion efficiency test. The tech found no cracks and combustion eff was 80.1%. He did find a loose clean out cover. (The tech did say he trusted his visual inspection more the the eff. test.) While I take the blame and thank you all for trying to guide me, I wonder why none of them really offered or recommended I have the tests?
    So now I can wait 'til the natural gas is installed and I don't have to go with propane as an intermediate step.

    Thanks again.
  • billtwocase
    billtwocase Member Posts: 2,385
    Amazing what a little gasket material, or even furnace cement will do on a warm air. Time to find a qualified service company, and dump these salesman guys
  • burnerman_2
    burnerman_2 Member Posts: 297
    Ok Just got on after a bit and saw you had a company find your problem... My guess you told the other two you were switching to gas .. so you may as we get a head start 80 per cent and 22 years old most company's do not want to be held accounted for today.. so many times the last guy there gets sued.. and by requesting you replace they were doing you a favor...