Condensation escapes

So we have been in our slab house how for 3 years and just noticed that we are getting water underneath out dining room floor. Come to find out it is coming from our AC unit.


While running, condensation is escaping from over the rear wall of the drain pan, being blown out through the gap between the coil box and air handler and finally running down the exterior of the air handler.


This is would be considered a blow-through or positive pressure system, since the A-coil is above the air handler. So the drain line for the condensate pan is just gravity fed (no traps, vents or clean outs) with a vinyl hose to a sewer drain.


I am just absolutely baffled as to how to keep the condensation from being blown over the walls of the drain pan. It is almost like there is a negative pressure inside the A-coil box.


Someone please help!

 

Sounds like a restricted drainline.

Have you tried clearing the drain?

 

Yes I have. Currently to verify the grain line is working I have it draining to a bucket. Seems to flow there with no issues.

 

I'd connect a wet/dry shop vac to the end of that drain.

 

Yep. Have done that already too. My next thing to try is to block the drain and "flood" the pan with a bleach water mixture. Try to make sure it is clean as possible. I've even toyed with the idea of using and appliance (fridge coils) brush to clean out the drain gutters.