Control Board or Transformer: Trane XB80 - http://www.hvacmechanic.com/ Forums

Original message

mark101

68.113.192.37

"Control Board or Transformer: Trane XB80" , posted Sun 17 Aug 18:48

Without warning, the display on my Honeywell t8601D Thermostat Went Blank, and of courrse the A/C is not operational here in the Texas Summer. Other unit in home works fine, and I switched thermostat faces without success.

I reset both the A/C and Furnance Circuit Breakers without success. I then checked the voltage between R and C and R and W and they both had zero volts.

In the attic, I opened the cover over the Trane XB80's control, and noted the LED was not flashing nor did it appear to have power (I made sure the cover switch was closed).

I checked all wiring for loose connections, etc. and did not find any. I also searched for a fuse on the control board to replace, but could not locate a fuse. Before I start replacing boards, etc. what else can I check and how?

Thanks!

Mark

Replies:

Houston204

98.196.66.53

"Re(1):Control Board or Transformer: Trane XB8" , posted Sun 17 Aug 19:24

Verify that you have 120 volts AC to the furnaace.
Check for line voltage to your transformer.

If you have 120VAC power to the transformer but no 24 VAC out, you probably only need a 40VA 24 volt transformer.

Frys has them at a Very cheap price.

You should locate and repair the low voltage short before replacing the transformer. It is probably outside by the condenser.

A low voltage fuse holder available at RadioShack along with a 3 amp fuse will prevent the need for more transformers the next time you catch a wire with a weed eater or an animal chews the wire.

"Tip of the Day" Remember to remove power first.