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Furnace full of water

conrajetken Member Posts: 10
I own a mobile home with a Miller Nordyne model CMF65-PO oil furnace which I fuel with kerosene. I’ve owned the home through two heating seasons. I serviced the furnace several times since I’ve owned the home. I’ve never before noticed any water coming out if the burner section of the furnace. When I went to service the furnace for the upcoming heating season I noticed rusty water coming out of the burner combustion section. I removed the Beckett burner to tune it up and I opened the fire box to clean it out. The combustion chamber was full of water up to the burner blast tube. I sucked the water out and removed the combustion chamber which was saturated with water. I found water in the steel hot side of the furnace where the combustion chamber goes. What could be causing this? It seems like way too much water for condensation although I did find the combustion gas exit ports in the back of the furnace to be pretty clogged with rust and debris. Could it be rain water entering through the exhaust stack. Thanks. Ken


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,132
    edited September 2019
    If you also have AC, you probably have a cracked condensate pan, and or leaking/cracked condensate line.
    Going to need a pro to open it up and fix it. Hopefully the furnace doesn’t have to be replaced.
    The furnace is very tight with little tolerance for error and needs to be properly serviced, and tuned with combustion instruments, not a DIY job.
  • conrajetken
    conrajetken Member Posts: 10
    No AC. I’m thinking the water must be coming in through exhaust stack but I went topside and the top of the chimney cap looks OK. Any thoughts?
  • lchmb
    lchmb Member Posts: 2,997
    Did the cap come off your vent pipe on the roof?
  • Jamie Hall
    Jamie Hall Member Posts: 21,110
    That's a perfectly good furnace. However, as @STEVEusaPA said, you are now in a position -- regardless of the source of the water -- where you need to get a professional in there to assess the damage the water has caused, and to repair or replace as required -- and then clean and adjust the burner. This is not a do it yourself proposition.

    I might add that in some jurisdictions, if a fuel burning appliance has gotten soaked like that, it must be replaced. Repairs, particularly to the burner and controls are not permitted. For good reason.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • conrajetken
    conrajetken Member Posts: 10
    cap didn’t come off the vent pipe
  • lchmb
    lchmb Member Posts: 2,997
    you need a pro to look the venting/unit over. That's a lot of water to have sneak into the system. I'd be looking at where the vent meets the roof. On top of a complete HX inspection. Small cost to make sure it's safe..
    HVACNUT Member Posts: 5,025
    A down flow furnace with water in the chamber. It stands to reason the water is coming from the chimney. The flue is 4", and usually sleeved through 6" exiting directly vertical through the roof. Waters getting in from somewhere up there. Flashing, storm collar, rotted flue. Its only 26 ga galvanized open to the elements so if its original...
    Obviously there's water in the HX and the chamber is probably shot so I wouldn't use it until a competent pro goes over the whole kit and caboodle. As said above, a combustion analysis must be done along with testing for an open HX. Definitely not DIY. You don't wanna wake up dead.