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  1. #1
    Join Date
    Jun 2008

    HVAC Paint Smell Follow Up


    Posted here back in March with an issue of a smell coming from my furnace that I thought was related to the fumes from the oil based primer I had used to paint parts of my home getting into the HVAC system. Basically a sweet smell coming from the furnace when it is firing but not when just the blower is on or the furnace is off. I have been busy with the rest of the rehab so the furnace wasn't really top on my list. So.....

    Had a HVAC guy come out this past weekend to try and figure out what was going on. We basically narrowed down the smell to the heat exchanger when the furnace was firing. There is a dusty film on top of the heat exchanger that looks kind of white but when you run your finger over it your finger is red from the oxidation on the exchanger...and the residue has no odor. He was quite stumped as to the cause of the smell and his only suggestion was to try and clean off that white residue. The residue just looked like years of dust built up to me but he said it looked odd and that he had not seen that before. He eliminated a cracked heat exchanger as the cause of the odor by looking at the flames and not seeing any roll-out. No other tests were performed.

    What I found odd was that he suggested removing the blower motor and rinsing the outside of the heat exchanger with a mild detergent and water. Seems harmless enough if I use a minimal amount of water, just wanted to get a few more opinions or suggestions on what this could be or if damage would occur if that method was used.

    Thanks for your time......

  2. #2
    Join Date
    Jun 2008

    Removed blower and vacuumed the outside of the heat exchanger. Bottom had some dirt on it but nothing major. I inspected the bottom as well and no holes or cracks that I could see. Sprayed down the outside of the heat exchanger with a mild water/bleach solution. Some minor surface rust was removed but nothing much came off. Dried everything out, put back together and fired it up...smell was still there.

    Decided to re-clean the inside of the heat exchanger. Found a large build up of white soot I had missed previously. It was in chamber of the heat exchanger that has the standing pilot. Cleaned it out with a brush then used a shop vac in reverse to blow the rest out. Put it back together, fired it up, and........the smell is still there.

    The only thing I can think of at this point is that the smell is coming from the insulation on the outside of the furnace around the heat exchanger. However when I pull a small amount out it has no odor at all...I am lost...


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