I have a 15 year old coil paired to 7 year old furnace that's never had this issue before. The primary condensate drain line is clear, yet it's dripping into/filling the secondary drain pan. What's more, it's also dripping 4' downstream of the coil from the end of the plenum, so much so that it soaked the insulation and is raining out of the can lights. Unfortunately, neither the secondary drain line shutoff switch nor pan overflow shutoff switch were triggered.

I pulled the cover off the side off the coil, and nothing appeared unusual or corroded. The coil and filter are clean, and the pathway between the coil and the primary drain are clear.

Why would condensate not be draining out the primary drain (unless there's a hole in the primary pan I'm not seeing)?

More perplexing, how is condensate suddenly reaching the end of the plenum?

I've had this issue on 2 separate units over the year. My problem was the primary pan (plastic) developed a small crack which then dripped all inside the unit and soaked up all in the insulation within the unit and then dripping out any screw hole or crevice it could find into the emergency pan and ceiling where the emergency pan wasn't centered under the unit. On the unit in our old house they had to pull the coil and replace the pan, the most recent time I was able to see the crack and fix it with flex seal. Good luck.

Thanks, I think it's a crack but I can't see it. I'm trying to pull the pan out from beneath the coil, but it's too heavy and the space too tight. I might have to wave the white flag.

Oh, and it has to be 130F in the attic

P.H. Dexippus said:

---

Thanks, I think it's a crack but I can't see it. I'm trying to pull the pan out from beneath the coil, but it's too heavy and the space too tight. I might have to wave the white flag.

Oh, and it has to be 130F in the attic

---

You could try a sealer/epoxy/resin in the pan to seal the crack if there is one. Just block the drain before pouring it. Spread it the best you can and let is set.

Maby something like this? It should self level if the pan is flat.
https://www.amazon.com/MTBJZJ-Crystal-Scratch-Resistant-DIY-0-5Gallon/dp/B08FBFXDG2/


If you can reach most of the pan by hand, you can try a asphalt based sealer. Thin layer should do it.
https://www.homedepot.com/p/Henry-107-Asphalt-Emulsion-Sealer-and-Dampproofer-Black-Roof-Coating-0-90-gal-HE107146/100083851

Flex Seal spray should also work if you can at least reach close to the areas in the pan but may not be able to get a brush/roller to it for the asphalt sealer.
https://www.homedepot.com/p/FLEX-SEAL-FAMILY-OF-PRODUCTS-Flex-Seal-Clear-14-oz-Aerosol-Liquid-Rubber-Sealant-Coating-Spray-Paint-FSCL20/300808900

Good ideas. I had planned to go with JB Weld WaterWeld
https://www.lowes.com/pd/J-B-WELD-WaterWeld-White-Epoxy-Adhesive/3389026

However, even though I disconnected the screws that held the pan to the coil, and can partially slide the pan + coil out of the plenum (until it conflicts with a duct), I cannot lift them apart. The coil appears to be resting directly on the pan for its entire length, so I hesitate to pour a resin in that will damn up against the coil and not seal any crack beneath it.

I called Wise Guys about a service call, I've been told to await a call from a sales guy.