The extension cord is not the correct gauge for the distance run. (14 AWG up to 25′ and 12 AWG over 25′)
Reset breaker.
Remove from area. Excessive moisture will trip GFI.
Check output does not fluctuate, as the unit will not operate at low voltage.
Verify voltage while unit is starting. Start up will cause the highest current draw and largest voltage drop. Even if plugged directly to outlet, there can be a significant voltage drop. Never assume the voltage is okay without verifying.
The unit shuts down and displays an error code.
ER 1: Overflow switch remaining closed for over two minutes.
Plugged or kinked drain hose.
Bad connection in pump circuit.
Defective condensate pump.
ER 2: Internal pressure switch indicates refrigerant pressure is too high.
Air filter is dirty or plugged. The coil is dirty.
Loose or faulty electrical connections to pressure switch.
Fan is not working.
Defective pressure switch.
Remove obstruction. Check
connections. Replace pump.
Clean or replace air filter. Clean coil.
Check connections.
Replace fan.
Replace pressure switch.
The unit continually ices up.
NOTE: Some ice buildup on the evaporator coil is normal, but airflow should not be blocked.
No warm air is blowing out of the back of the unit.
Air filter is dirty and airflow is obstructed.
Dirty evaporator coil.
Ambient temperature may be too low. Raise temperature with supplementary source.
Clean filter. Unit should have a minimum of 10″ clearance all around it.
Clean coil.
Unit moves some water, but not as much as expected.
Air filter is dirty or airflow obstructed.
Evaporator coil dirty.
Restrictive or kinked exhaust ducting (if used).
Unit should have a minimum of 10″ clearance all around it. Clean air filter and ensure adequate airflow/space around unit.
Clean coil.
Straighten out ducting.
Fan does not run. Compressor runs briefly, but cycles on/off.