In a typical downdraft furnace system with central AC (evaporator coil) located in a walk in attic space, is a secondary drain pan and condensation drain pipe required? and if so, how and where would it be installed. I know drain pans are installed under horizontal flow systems, but not sure about the downdraft install.
In a typical down flow furnace standing upright in an attic space there would be no place to install a safety pan. Bad idea to do this because at some point in the life of the unit the drain pan is going to over flow and damage what ever is beneath it probably a sheet rock ceiling
Evaporator coil drain pans have a secondary drain overflow connection. There are secondary overflow traps with float switch.
They protect from water leaks that never make it into the evaporator pan?
If the pan is cracked, how will the water get up to the secondary overflow outlet?
John: if your client really has a concern about this, there is a device that senses moisture overflowing into the supply air duct below the unit and will turn off the air conditioner just like a float switch.
Thanks Dave. I might suggest that as they are concerned about it. There was a water stain at the plywood floor below the supply duct (perimiter of duct), no visible corrosion on duct which I attributed to condensation issues (duct not insulated), but it did raise the question about possible leaking from the evaporator coil.