I once had a contractor that actually installed my A-coil upside down. He said that the previous contractor had installed it upside down with the drip pan on top! The previous contractor had made his own drip pan to put under the coil, and that had corroded, disintegrated, and leaked water all over the downstairs ceiling drywall. A short time after he reinstalled the coil, it leaked again. This time water was getting blown around the drip pan. He remedied this, but when he wouldn't pay for the drywall damage, I moved on to another contractor. Good thing, because I then learned that the original contractor actually had the coil installed correctly, and my contractor had reinstalled it upside down. It turns out that when using this A-coil in a Carrier downflow unit, you were supposed to install it with the drip pan on top, and provide your own drip pan on the other side, just as the original contractor had done, and my contractor had "corrected".