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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8326
Experience:  Furnace, A/C and heat pump specialist.
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Just replaced the motor and capacitor in my trane xr80. But

Customer Question

Hello...just replaced the motor and capacitor in my trane xr80. But the fan will not come on, whether i set it to cool or just fan. I bypassed connected the motor black wire to the door switch wire just to see if it works, and it spins up fine. I am assuming i have a bad board...would you agree?
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: my motor siezed up on Saturday...just got the new motor today
JA: Do you plan on doing the work yourself?
Customer: already am....the new motor and capcitor is installed
JA: Anything else we should know to help you best?
Customer: it has been 100 degrees out every day...i need to get the fan running, if only temporarily, to cool the house down
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

1.Do you have a meter for troubleshooting?

2. Give me complete model on furnace from label inside (Something like TUD08E

3.Tell me where you have fan wires connected on board

Customer: replied 1 year ago.
tud1b080a9481aa......I took pictures of the wires before I took the old motor out and replaced them exactly the same....Black=cool, blue =heat, red and yellow are park....white I could not read the text...but is on the same terminal
Customer: replied 1 year ago.
I can send pictures if it helps...
I do have a meter if I need it...
Expert:  airheatman replied 1 year ago.

Let's do this. Turn thermostat to COOL. Take the meter and check between the Black COOL terminal and WHite NEUTRAL and verify we are sending 120v to motor. (Door switch will have to be held in of course)

Customer: replied 1 year ago.
with the fan on auto and the thermostat on cool I measured no power
Expert:  airheatman replied 1 year ago.

Door switch IN?

Customer: replied 1 year ago.
I had the door switch depressed...
Customer: replied 1 year ago.
yup
Expert:  airheatman replied 1 year ago.

OK does outdoor unit come on?

Customer: replied 1 year ago.
it is not on....wait...let me try again
Customer: replied 1 year ago.
no, it did not come on
Customer: replied 1 year ago.
it confused me because it was coming on this past saturday when I discovered the bad motor
Expert:  airheatman replied 1 year ago.

Check the little fuse on the furnace board and make sure it is not blown

http://i.imgur.com/kYe4Epz.png

Customer: replied 1 year ago.
the fuse is good
Expert:  airheatman replied 1 year ago.

Next check for 120v into transformer from XFMR terminals and then 24v out of transformer

Customer: replied 1 year ago.
ok...be right back
Expert:  airheatman replied 1 year ago.

Take your time

Customer: replied 1 year ago.
transformer is good
Expert:  airheatman replied 1 year ago.

OK lets do this next. On furnace board, connect the R to G where thermostat wires hook up and see if blower comes on

Customer: replied 1 year ago.
you want me to disconnect both and connect the red wire to the green terminal and let the green wire hang? Just clarifying...
Expert:  airheatman replied 1 year ago.

You can leave wires connected. Use a jumper or a pair of needle nose pliers to touch R terminal to G terminal (Door switch IN)

Customer: replied 1 year ago.
nothing changed
Expert:  airheatman replied 1 year ago.

OK if we have 120v into transformer, 24v out of transformer but no blower with R and G connected an no outdoor unit on call for cool with fuse intact you have a bad board.

Customer: replied 1 year ago.
I was afraid of that....is there any way to force the ac to turn on or even just the fan until I can get a new board in?
Customer: replied 1 year ago.
do you have the pn of the board?
Expert:  airheatman replied 1 year ago.

You can connect the black fan wire to the XMFR to pick up power but it will run nonstop.

Expert:  airheatman replied 1 year ago.

Part #CNT05165

If you have further questions, please let me know.

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