The Downflow Furnace Condensate Is Not Draining

Locate the condensate drain on the downflow furnace, which is usually on the side of the furnace and connects to a household drain or runs down to the house exterior.

Disconnect power to the furnace. Remove and empty the condensate drain trap if water has built up in the drain trap.

Use a hair dryer to melt the ice if the condensate drain is frozen over. Wipe up the extra moisture with clean towels.

Remove the tubing connected to the condensate drain and clean away any obstructions. Reconnect the tubing.

Mix together 1 cup of household bleach with 1 cup of warm water. Find the opening from the top of the condensate line that follows down to the drain and pour the mixture down the drain to clean away any remaining debris or mildew. Check to make sure the bleach mixture exits the drain. Repeat with water until the water flows freely out of the condensate drain.