American Standard Heating & Cooling - Page 8 - Recent Questions, Troubleshooting & Support

Hi you can actually check the relays on the circuit board to check if it really does it part which serves as triggering device with other accessories.Thsi might be the problem why yuor motor sometimes does not engage.You can open the panel circuit board and check both ends using a MULTITESTER.You have to unplug first ac source.Check the continuity of the relay using a TESTER setting it to OHMS value.Now if the reading kicked off to its maximum it means relay is not working anymore..Hope this helps.Thank you for choosing fixya..

need more info does it have line voltage and control voltage if so could be ants in contactor,or capacitor open

This is a two piece unit with an outside compressor? If there is no power to the thermostats, check the power at the inside unit. There should be a fuse and a transformer there. Check the fuse and if you have a volt meter, check the voltage on the secondary side of the transformer.

You may want to check the limit switch or you could have a issue with the gas valve or transformer. I would check the low voltage transformer first, Sometimes I have found that under load the transformer will open ( quit working) and will close after power is removed and it cools down, It indicates a bad internal connection.

Do you have 3 or 4 wires coming from the Motor?

Hook a set of ac guages to the high and low side of your system and see what your pressures are. ballpark low should be 55 psi and ballpark high should be 350 psi. If off replace inline filter on high side, vacuum system and recharge with specified capacity and check pressures again. check to make sure clutch on compressor engages when you turn your ac on. if no charge in system clutch will not engage

First, Open the Blower Access panel door of your air handler and touch the motor to see if it is hot to the touch.
If it is hot to the touch, turn everything off of approximately 1 hour.
Then with the blower access panel door off, turn the FAN back on and listen for any sounds. If the motor does not start, try spinning the blower wheel with your hand.......be cautious, because the motor could start up while you turn the wheel. If this happens, chances are good you have either a bad capacitor or bad bearings. To test the bearings, turn off all the power. Grab the end of the shaft and start trying to move it from side-to-side in every direction. Do not move it up-and-down. Up-and-down will not hurt anything, but it will not tell you anything either. If there is any movement side-to-side, the bearings are bad and the motor will need to be replaced. If you do not feel side-to-side movement, then there is a good chance it's the capacitor.....take to A/C supply house....they will test and offer you a replacement if it is needed.
If the motor is cold and it doesn't try to spin and it doesn't try to run on it's own after you spin it, then the problem is in the control circuit. Try putting a jumper at R & G. If the motor then runs, you have a problem with either your thermostat or the wiring from your thermostat to your Air Handler. If after jumpering R & G the motor does not try to run, then you may have a failed blower relay or a failed board (if the relay is internal in the board). Let me know if you need additional help. :-)

Check motor winding resistance (line to line and line to body). If this is okay, check if the wires are cut or disconnected to the terminals. If wires and connections are okay, replace the capacitor.

It sounds like the tech was referring to the blower relay. The blower relay on this unit originally had a small circuit board mounted to it. It's only purpose was to allow for delay off-time of the blower at shutdown. In other words, once the command for the blower was de-energized, the blower would continue to run for approx 90 secs. This is something that is optional. It does slightly enhance the operation of the air handler; however, it is not something that is absolutely necessary. It is possible to replace the relay with a standard type blower relay; however, it will require it small bit of re-wiring. Your service tech should be able to help you. I would recommend that you use the service tech. This will prevent possible mis-wiring which could damage your blower motor (very costly) and most service companies offer a 1 year warranty on the parts. However, if you are going to try to do this yourself, the part can be obtained from Grainger or an Air Conditioning Supply House for approx $20.00. The blower relay is a 90-340. If you purchase it from a contractor, it will be approx double.......every business marks up their product, it's how they make money.
I'm attaching a link to a site that has the specs and a wiring diagram for your air handler.
I hope you find all this information helpful and I wish you luck in your endeavor. :-)
http://74.125.155.132/search?q=cache:7UZFtDiHEyQJ:www.trane.com/webcache/un/split%2520system%2520air%2520handlers%2520(ssa)/product/22-1222-03_10011993.pdf+Trane+model+TWV-&cd=3&hl=en&ct=clnk&gl=us

Most likely it is a bad motor bearings. The bearings are not replaceable verify the motor is getting power and it it is replace the motor. There is a slight chance it has a bad run capacitor but not likely