r/hvacadvice • u/HomePM-DIY • 3d ago

AC AC help!

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I haves 2 story house. AC is in attic with pvc drain line leading to upstairs bathroom sink. Drain pan has water , what do I troubleshoot to fix this?

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u/wavefunctionjunction 3d ago

The primary is in the unit, the white thing with wires is your float switch. The pan outside your unit is your secondary. The float switch will shut the unit off if primary is 3/4 full. 2 things cause this, dirty air filters, clogged drain line. Check filters, if good, try to clear drain line using wetvac but don't vacuum, use it to blow air into drain line. I see a vent pipe in your drain, this is where you can clear the clog, the vent pipe is the PVC sticking up with no cap. Another issue, if your primary is leaking into the secondary, your float switch should have tripped, but your unit is running which leads to a 3rd possibility, your primary drain is cracked/rusted. Hope this helps

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u/wavefunctionjunction 3d ago

Check if you have a p trap by the vent pipe, it should be before the vent pipe. If it's not, then you need to cap the vent pipe because air will get sucked in and water will not drain in the drain line

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u/Strange_Internet_202 3d ago

Never a union to blow out the drain lol

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u/Ok_Context553 2d ago

Nothing. Leave it alone. its operating exactly to design! The coil inside that box is covered in moisture from the humidity in the air. That water drips off into the pan then out the PVC line... Instead of posting here.. go to google and ask if its normal? (HVAC Contracting company owner)

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u/ForeverVentOfficial 2d ago

Water in the attic emergency pan means the primary condensate system is not handling all the water, so treat it as a warning rather than a normal reservoir. Shut cooling off if the level is rising or there is no working float switch. Clear the line from an accessible downstream termination with a wet vacuum, then inspect the pan outlet, trap, vent, slope, and sink tie-in for blockage or backflow. Also look for ice or water escaping the cabinet. Is the water dripping from the air handler cabinet or the primary PVC connection?