MY PRIZM AC Unit only cool for about 20 minutes in test mode but only the fan blows in regular mode when you use the remote. Only the power light shows and it will not cool or do anything else. But when you press the button on the unit itself to operate it in test mode it cools for about 20 minutes then the air return to room temperature. [email protected]

It's dirty. You will have to take it out and remove the outside cover and the cover to the inside coils. Then spray it down with foaming alkaline coil cleaner diluted one part cleaner to two parts water, wear good thick rubber gloves and eye and face protection and a rubber apron. Spray on coil cleaner and wash out. You will need to dump out water and repeat several times and make sure to clean out drain between front coil pan and rear. Keep water off electronics, especially the top of capacitor for compressor and fan. Let dry in sun and you will be ready to go for another year. Clean yearly.