paul s

Need help, Evaporator fan should come on minutes before the compressor starts, but now the fan does not start until the compressor starts and then it moves only a small amount fwd and reverse. found a loose line wire at the breaker in the air handler, tightened it but did not help. can anyone give me some ideas. thanks

glennjanie

Welcome Paul:
Check to see if there is a capictor on the fan motor. If there is you can check it by removing the wires from it, using an audible ohmmeter touch both the contacts on the capicitor, your ohmmeter should go immediately to a high whistle or whine and taper off to a low pitched sound.
See if the fan turns freely with the power off. Follow all the wires to the fan and make sure they are all connected. If the unit is over 10 years old you may need a new motor, take the old one with you when you shop for a new one.
You may want to try United Refregeration, Grainger or ebay.
Glenn

paul s

Thanks for the info, The unit is only a couple of years old. cant see any start copacitor. motor has about 20 wires going to it. it is a trane unit with variable speed. there is a circut board with a bank of dip switches on it and 4 green lights. one green light labled cfm blinks continously. maybe this is a troubleshooting clue. I need to find someone who knows this unit. thanks again.

glennjanie

Hello Paul:
See if you can find the Trane dealer that installed the unit; it should be under warranty. Your problem is in the computer board and they will have the key to the blinking lights.
Glenn