Drain Pan in Attic

Is a secondary drain pan required if the AHU is vertical in the attic? If so, could someone give me the IRC reference? Thank you

Does it have coils?

Do you mean drain pan or drain line from the drain pan?


M1411.3.1.1 Water-Level Monitoring Devices

On down-flow units and other coils that do not have secondary drain or provisions to install a secondary or auxiliary drain pan, a water-level monitoring device shall be installed inside the primary drain pan. This device shall shut off the equipment served in the event that the primary drain becomes restricted. Devices shall not be installed in the drain line.

I think the idea is that if there is no backup drain option, an automatic shutoff should turn the equipment off if the water gets too high

That’s the idea. The question is vague due to the fact that there has to be coils. Otherwise there is not any condensate.
The wording of the provisions is key

Overflow pan.
Pic and MN# of the evaporator cabinet in the attic please. Might look like this, without the corrosion.
overflow pan