Thread: AC Condensate Line Blowing Cold Air Into Sink?

Wrong Section. Sorry about that. I have moved it appropriately I believe.

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Everything is correct assuming the condensate is allowed to be sent to the city sewer (that is a ordnance issue only). What has happened is the trap in the attic near the air-handler/evaporator coil has dried out. This happens during long periods of none cooling. One solution is to remove the cap and pour a 1/2 cup of water into the trap through the cleanout; longer lasting results can be obtained by using mineral oil that does not evaporate as quickly.

I just looked at you diagram and did not see a trap in the drawing. There needs to be a trap at the cleanout.

Hi Vern,

Thank you very much for taking the time to reply! There is not a trap anywhere between the condenser and the sink. Does not having a trap at the clean out cause any damage or problems?

Originally Posted by JTravis

Hi Vern,

Thank you very much for taking the time to reply! There is not a trap anywhere between the condenser and the sink. Does not having a trap at the clean out cause any damage or problems?

The lack of a trap is what is allowing cold air to blow out of your sink drain. I am guessing that you are in cooling mode, somthing I did not originally think of. The condensate trap is more important on a heat pump than it is with air conditioning system with a furnace. Don't know which system you have.