Filter in wrong spot?

I ran across a Trane (American Std) Air Handler with Electric Heat that based on model number 2TEC3F42A1000AA, it is a Airtite Air Handler which can be put in any configuration, A/C coil with 42MBTHu cooling. It is configured in a Vertical up mode so I am guessing from what I can tell that cooling coil in bottom and fan in top. Serial number is 62213CN51W (so 2006 Model I believe)

Problem is, the enclosure is dented at bottom and it has an air filter laying down in it which would be hard to get in and out.

Looking at the C-channel rails, I am wondering if there was supposed to be a drip pan below the coils right there and wondering if the air filter is actually supposed to go in the duct above.

If the filter is supposed to go there, it seems totally the wrong size or something.

Any help would be greatly appreciated. I admit, I am a bit clueless on this one and cant find a good diagram on-line

Warm regards







You are correct. Filter is too small and fell through. There should also be a cover to seal the installed filter.

Is it located in a garage ?

The access panels on that AHU come off easily, open it up and inspect the configuration; you’ll see the fan, coil, drain pan, etc and be able to understand the airflow and where the filter should be. Filters frequently are installed incorrectly (wrong size, wrong type, etc.)


Any time a return filter has been bypassing the air flow across the A-coil I always recommend having the coil fins cleaned as they will most likely be matted with lint restricting air flow. The proper placement of the return air filter should be a standard check for a home inspector.

I have had several cases where an additional return duct was installed in a master bedroom after the original installation of which return air filter grills were originally installed with filters in the ceiling but the master bedroom had just a standard grill with no filter thus sending unfiltered air to the A-coil.

Checking all aspects of the return air system should be standard protocol for a inspector.

Its room attached to garage, separated from living area. It is electric, not gas though.

Thank you everyone! I appreciate the assistance.


You’re on the money.

The bent housing will not seal at the filter allowing air to bypass and as Jeffrey said it is missing the cover.

Your picture also shows the drain line has a trap. Not needed. Over time it will collect debris and stagnate water during the less a/c used and heating months and clog. Usually, there is a “T” in the drain line that acts as a vent to keep it free and clear.