Cooling - Condensate Leak

Article ID: 308
Last updated: 10 Jul, 2017


Re: Condensate Leakage

The air conditioning condensate is leaking from the a/c coil instead of running out the drain.

Qty Possible Causes:
1 Clogged Drain Pipe
Frozen Coil
Hole in Drain Pan
Condensate Missing Drain Pan
No Drain Trap (Heat Pump)
Double-Trapped Drain


1. Identify the Source of Water

  • Try to identify where the water is coming from.
    • Is the water coming from the coil, from sweating ductwork or lines, or from leaking pipe joints, etc.

2. Check the Indoor Coil

  • Check the indoor coil to make sure that it is not frozen.
    • Even without ice on the lines, the coil can be partially frozen.
      • Frozen Coil --> Turn the A/C "Off" and allow the indoor fan to stay running until coil completely thaws.
        • Be prepared for large amounts of water as the coil thaws.

3. Inspect the Drain Line

  • Inspect the drain line and make sure that it is properly installed & properly sloped.
    • On a heat pump system with the drain on the "return-side" of the blower, make sure that the drain is trapped before any open air vents.

4. Check the Drain Pan

  • Remove access panel to indoor coil.
  • Inspect drain pan for standing water.
    • Standing water in the drain pan above the drain outlet = Clogged Drain or Double-Trapped Drain
    • Empty Drain Pan --> Pour water into the drain pan and make sure that it exits through the drain line.
      • Water leaks from drain pan (doesn't overflow) = Hole in the Drain Pan

5. Examine the Coil in Operation

  • If possible, observe the coil and drain while the system is operating.
  • Look for water that is blowing off of the coil and missing the drain pan.

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Article ID: 308
Last updated: 10 Jul, 2017
Revision: 4
Access: Public
Views: 60
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