Trane makes both furnaces and air conditioning units for homes around the U.S. Like all units, Trane furnaces and air handlers have drain lines for any condensation to drain out of. If the drain lines are cleaned they can get clogged with mildew and algae. Cleaning the clogged line and keeping it clean regularly will prevent it from getting clogged again.
Turn off the furnace or air handler unit and open the service door. Open a window in the room or turn on a fan to ventilate.
Remove the cover from the top of the drain line and place the funnel inside of it. The covers should unscrew.
Pour 1 cup of bleach into the drain line and allow it to drain into the drain pan. Rinse the drain line with 2 to 3 cups of hot water to completely clear out the clog.
Rinse off the drain pan with water and replace it in the unit.
Clean the drain line once a year to prevent clogs.