I am an AC contractor. I did a change out on an apartment complex of some air handlers (dx open case, twin squirl cage, ceiling mount, hide-a-way type.) The air handlers have electric heat strips with a r22 evap/coil w/ txv's. When winter began I got numerous complaints of no heat. The heat strips are cutting out on the high limit safety disk and the fuse-links. The manufacturer is not being very cooperative in rectifying the problem. The heating elements are the ones that look like long "U" tubes. They are over-heating from not getting much air across them coming out of the two 4" x 6" blower ports.
Has anyone else out there used these units and have had the same problem. I replaced one of the air handlers with another brand unit with the curly-cue type heating elements that are located right in the air streams of the two 4x6 blower ports and it runs just fine.
If anyone had or has this problem also, please let me know.