Clear a clogged AC condensate drain
Monsoon humidity makes your AC pull more water out of the air. If the drain line is slow, that water ends up in the pan, the ceiling or the closet floor.
What to watch for: The first half, the wet-dry vac at the outdoor end, is the homeowner fix. When he cuts the drain pipe and opens the air handler, that is the point to call a pro instead.
Why does this matter in Tucson?
At Tucson's airport, average dew points sit in the 20s for most of the year and jump into the high 50s in July and August. Wetter air means the indoor coil wrings out much more water, and a drain line that slowly grew a film of algae and dust suddenly can't keep up.
Many systems have a float switch in the drain pan or the line. When water rises, it shuts the cooling off to protect your ceiling. So an AC that quits on a humid monsoon afternoon, with the fan still running, is often a drain problem, not a broken compressor.
What you'll learn
- Why a drain that was fine in May can back up in July
- How to find where the drain line ends outside
- The wet-dry vac trick that pulls most clogs out in a minute
- Why the AC may refuse to run until the drain pan is empty
How do you do it, step by step?
- Turn the thermostat to Off.
- Find the end of the drain line outside. It is usually a small white PVC pipe near the outdoor unit, at the foundation, or on the roof edge for a rooftop unit.
- Fit a wet-dry vacuum hose over the end of the pipe. Wrap a rag around the joint to seal the gap.
- Run the vacuum for about a minute, then check the canister. Sludge and a gush of water mean the clog came out.
- If the air handler is in a closet or attic you can reach safely, look in the drain pan. If it is full, the safety switch may reset once it drains.
- Restore the thermostat to Cool and watch the outdoor end over the next few minutes for a steady drip.
- Before pouring any cleaner into the drain, check the air handler manual. Never mix vinegar and bleach.
When should you stop and call a pro?
- Water is coming through a ceiling, light fixture or wall.
- The vacuum pulls nothing and the pan stays full.
- The drain runs into a condensate pump that hums but does not pump, or the line has to be cut open.
- The air handler is in an attic you can’t move around in safely.
If water is near any electrical fixture, turn the system off at the thermostat and the breaker before you do anything else.
Read next
Rather have a pro handle it?
Climate Pros Tucson matches homeowners with licensed local HVAC pros across the Tucson area. You talk to us, then to the pro, and the pro quotes the job before any work starts.
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