said by alphapointe:1: The pressure was dropping through the air dryer because it was freezing up. I put a temperature logger in the mechanical room, and it was getting to about 45 in there...
So the mechanical room is unconditioned space?
They should put a heater in there, or crank up the heat if it's already heated.
Obviously, since the air dryer functions by condensing moisture from the compressed air, it wont work if that air is already very cold.
Oh, and that's kind of a crappy air dryer for it to freeze like that. A good one should have a thermostat to provide better temperature regulation and prevent freezing.
Although, you are operating it probably well below its intended ambient temperature range.