Online instructions for troubleshooting and repairing a portable air conditioning unit are available at hvac-for-beginners.com, DoItYourself.com and Air-n-Water.com. All three sites address fixing a portable air conditioner that does not start or starts but does not cool.
Portable air conditioners with water reservoirs shut off when the reservoir is full. Units cannot start if the power cord is unplugged or the circuit breaker is turned off. Damaged cords or malfunctioning outlets may also prevent the unit from starting. Portable air conditioners that don't cool may be too small for the room or may have frozen coils. Clogged filters and dirty coils also reduce an air conditioner's cooling capacity.