What is the current thinking about air handlers in attics. Did the energy/building code simply make that go away?
I do see them in garages now but I am curious with how they deal with the firewall penetration.
I guess the plywood attic access door makes that moot anyway.
I do remember when attic installation was a common thing that electrical folks were questioning how you get working space for the disconnect or if it was required.
Maybe I don't understand all I know about the code but I don't see how the current garage installations are legal either.

If you are talking in a residential application, the NEC will permit the installation. A disconnect may be used at the unit or a lockout is permitted in the panel per NEC 424.19.

The FMC 306.3 permits appliances in attics and provides requirements for such.

FBC Chapter 13 (Energy Code) chapter 6 for residential applications section 610.ABC.3.5.2
permits them to be installed in attics but requires the following conditions to be met:
1. The service panel of the equipment is located within 6ft of an attic access.
2. A device is installed to alert the owner or shut down when the condensation drain is not working properly.
3. The attic access opening is of sufficient size to replace the air handler.
4. A notice is posted on the electric service panel indicating to the homeowner that the air handler is located in the attic.

Hey does anyone know if the new IBC has those same requirements for AHU in attics? Is it the same text? I am just curious what we are all in for come the change.

What ever happened to having to box these in if they were in the attic? Was that just a S Fla rule that went away with FBC?

I also remember a lot of yacking about having full 110.26 working space for the disconnect.
I see them hanging 10 feet off the floor around here in a garage, disconnect next to them.

That is an old code rule and is long gone and not part of the FBC.

You are correct in that the disconnect means must comply with 110.26 for working clearance with the exception of the 6 1/2ft height requirement of 110.26(a)1 & 2, and 110.26(e), since this is just an equipment disconnect and not a service, switchboard, panelboard, motor control center, etc.

404.8(a)exc(2) permits the disconnect to be located higher and accessible by portable means. This requires the disconnect to be accessible but not readily accessible.

It is interesting to note that for motors 430.107 only requires one disconnect to be readily accessible. That’s why for like industrial machinery sometimes disconnects are mounted on the equipment in locations that would not be considered as readily accessible, because another disconnect for that equipment / motor is.

In addition don't forget that 424.19 permits a unit switch as the disconnect means.

So if the air handler has the breaker mounted in the unit,(some units have that provision by the manufacturer) than that is your disconnect and another isn't required.

OK thanks

Does the FMechanicalCode require disconnects within 6' or did that go out with the StandardMCode?

The florida mechanical code dropped the 6 foot rule and defers to the nfpa 70

Most of the air handlers I have looked at don't have a disconnect since they are within sight of the service panel. There may be something integral to the unit tho. These puppies are 10-12 feet in the air in a garage.
In a "stem wall" home the garage is at grade, the house ceiling is 10' in the house so the garage floor is 3-5 blocks lower than that, depending on flood elevation.