Indoor unit runs but water leaks from around the air handler or furnace during cooling

Safety first: Turn off power to the indoor unit. Water and electricity are a dangerous combination.

Steps:

• 1. Locate drain line: Find the PVC drain exiting the evaporator coil pan. Identify the cleanout or trap.
• 2. Clear blockage: Remove the cleanout cap and use a wet/dry vacuum on the outside drain termination to suck out sludge and algae. Alternatively, use a small brush or flexible wire to break up clogs near the pan.
• 3. Flush with water: Pour warm water mixed with a small amount of mild detergent or vinegar into the drain pan or cleanout to flush the line.
• 4. Inspect pan: Use a flashlight to check the evaporator drain pan for cracks or rust-through. If damaged, the pan or coil assembly may need replacement.
• 5. Verify slope: Ensure the drain line slopes continuously downward away from the unit.
• 6. Install float switch (recommended): If not present, consider having a technician install a condensate safety switch to shut off the system if the pan overflows.