A new addition to my "Find Out the Hard Way Chronicles."

I cleared out the primary AC drain a couple months ago, and unbeknownst to me, it had become clogged again. I found out when I got a message from my AirBnB guest saying there was water dripping from the ceiling. I checked the overflow drain outlet and it was not dripping. Went up in the attic and the insulation was wet and there was standing water above the sheetrock, but no obvious source of the water. The drip pan had about 1/4" of water in it, but not enough to drain through the overflow line.

It turns out when the primary drain line clogged, it caused water to backup into the air handler, and the blower forced the water into the plenum before it could drain into the drip pan. The water then percolated through the foam board plenum box and into the attic - beyond reach of the drip pan.

Thankfully I don't have a giant AC repair bill, but I still have some sheetrock repair to do.

Had something similar happen last year. Coil froze several times (later determined to be due to a leak), but when it would thaw, the chunks of ice would break off and fall outside of the internal drain pan, allowing ice melt to reach the plenum and drip outside of the external pan.

Jason_Roofer said:

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Do you have one of these?


https://www.supplyhouse.com/Rectorseal-97637-Safe-T-Switch-Model-SS2

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AC guy recommended something similar.

Install a better pan as well.

Even better, don't put water above conditioned spaces!

You are reading my mail ... in a 80's Usonian style house.

Not a richy like some clients that can afford the SF for a HVAC closet & floor drain
so attic HVAC for the majority of us.

History teaches that a licensed plumber should come in after the HVAC install = saves the money in spades in repairs, damage to materials, emotions and future concerns. Shouldn't be this way but ..... SIGH

Govee has leak dection sensors that are great. Put one in your pan and it will make an super annoying sound and send notifications to your phone as well when water is detected.

Edit: It doesn't shut off the AC unit, but assuming you have a smart thermostat you can just do that whenever you see the notification that there is water. Happened to me twice with clogged lines since I've had them. The guys who installed my units back in 2020 did terrible job and the new PVC runs are constantly clogging.

howdydamnit04 said:

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Govee has leak dection sensors that are great. Put one in your pan and it will make an super annoying sound and send notifications to your phone as well when water is detected.

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+1. I have these and they are great. I also now have the govee freezer alarms too.

TexAg1987 said:

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I have one installed on mine and it turns off the A/C completely when tripped.

When the screen on the thermostat goes blank, I know I have an issue starting.

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I have one on mine and it is a great early warning system.

As soon as the thermostat goes dark, it is time to climb into the attack and clean.

tgivaughn said:

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Not a richy like some clients that can afford the SF for a HVAC closet & floor drain
so attic HVAC for the majority of us.

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Is that really the reason why new homes put the air handlers in the attic?

I've got a single-story home built in the early '90's with two A/C's, and the air handlers are both located in hallway closets. At most they take up about 12 sqft a piece. I'm definitely not a 'richy', nor is my home some showplace but it is comfortable and in a nice neighborhood.

I figured it was some kind of conspiracy (yes, I guess I'm one of those nuts) by some sadistic A/C guys to put them in inaccessible and uncomfortable places so you'd almost have to call a 'pro' if something (even a minor electrical part issue) malfunctioned.

Personally, I'd be very reluctant to buy a house with an attic unit, but it sounds like that's the standard practice these days?

Kudos to you, not all of us are so blessed.

Indeed, all we can do is try try try to get them to a closet + floor drain but ample closets are big spec/tract.house sellers.

Custom owners will X them out when proofing/annotating their plans in progress but then ask for a gun safe/other small elephant that's handy.

When the SF get to be over 3000sf, then more progress is made.

Some mansions over 5000sf have Owners that travel. They may have a house sitter but still want HVAC exterior closets with keys sent to the maintenance company for tuneups twice/year. Convenient & secure events but sometimes not as efficient a HVAC system.

Odd: I did have one or two clients decades ago that complained about HVAC noises, even if walls packed with rockwool & a solid core door hung for sound mitigation. These did not have closets in the end.

Each to his own ...........