Originally Posted By: dandersen
This post was automatically imported from our archived forum.
There are numerous reasons for condensate problems beyond the obvious blocked drain.
Drain pans with drains often get clogged up by either pests entering from the outside or blown insulation into the pan from the inside. A heavy wind (especially in the Windy City) can blow this insulation at any time into the pan which will clog up the drain when needed.
Condensate drain pans only cost six dollars (however cost $75 for installation)!
Regardless, this is much cheaper than replacing a finished ceiling below!
As for testing the pans switch, if the unit is running in air-conditioning while you're in the attic, place something like a screwdriver under the switch for a minute while you check the rest of the furnace. You can hear of feel the refrigerant flow stop. When you remove the screwdriver, the lights should blink when the compressor turns back on. Or, run back outside and make sure the condenser is off when you activate the switch. You can often see the fan from the interior by way of a window tp shorten the trip.
Pan switches are wired in different configurations and it is possible for them to be miswired and never tested, so I would recommend testing.
A non-heat pump system should be wired into the two wire thermostat wire that goes to the outside condensing unit.
A heat pump will commonly drop the 24 V power supply to the control circuit.
It is not recommended that you drop the 24 V power supply to the thermostat on a non-heat pump system as any switch defect will shut off the heat as well. We don't want the house to freeze. No heat is much more serious than no cooling.