I noticed today a yellow waxy liquid dripping from the ducts that run from the furnace to the vent in the roof. It looks like it is coming from inside the tube and out the seam, not from around it. The furnace has been running much more lately with the cold. The substance doesn't have a smell when dry, I haven't caught it wet, but I know it is still dripping because I keep cleaning it up. Any ideas what this is?

It could be dried condensate water.

Brand of unit?

Exact model number of unit?

% of efficiency?

Gas? Oil?

Thank you for response. It is a Carrier, I can't find the model number, but it was installed in 06. The efficiency rating says 80.0. it is gas.

How would I know if it is dried condensate water? What should I do if it is and how urgent is it?

I would have it checked now since anything that has to do with possible flue gas/condensate is nothing to fool around with. The 80% style units should have enough heat left to carry away the condensate with the flue gas UNLESS the flue/chimney is sized improperly or the unit is not operating correctly.

We had it checked out. When they installed the furnace they did not update the flue, and the pipe was not the right kind for the unit. Also there was no flue cap, so cold air was coming in and meeting the hot air and causing condensation, then since there was no liner it was dripping down the flue and into the laundry room. The company that installed it originally came and totally replaced all the flue piping from the furnace to the attic. Thank you for your help!

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Originally Posted by bethjones

We had it checked out. When they installed the furnace they did not update the flue, and the pipe was not the right kind for the unit. also there was no flue cap, so cold air was coming in and meeting the hot air and causing condensation, then since there was no liner it was dripping down the flue and into the laundry room. The company that installed it originally came and totally replaced all the flue piping from the furnace to the attic. Thank you for your help!

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It is good you got the situation taken care of. Hopefully you will have no more problems.

I have the same kind of substance but on my soffit outside. Its yello, and when it drips and falls to the ground looks like wax. Any ideas?