On 4/8/2011 8:52 PM, Steve Turner wrote:
A continuation of the "Why does the 115V-24V transformer keep blowing
on my Trane XB80?" discussion I started on 04/02/2011.

Yep, My A/C unit blew another transformer. Pictures (and wiring diagram)
he

http://www.flickr.com/photos/bbqboye...7626457562742/

Trane's manual for the unit is here (for perhaps better viewing of the
wiring diagrams that I also copied to my above flickr site as jpg images):


http://www.trane.com/webcache/un/fur...7_04012009.pdf


As you can probably see in the pictures, there is visible charring of
the 115V leads going into the transformer, and of course the 115V
circuit is open (again).

Three times it fried the primary? I'd guess it's getting 240vac at
times. It's very unusual for the primary to go bad from a short on the
secondary side, and the picture shows that the secondary wasn't
overheated like the primary was. Where's all those electricians talking
about an open neutrals when you need them? If it measures 120vac tie a
light bulb into the primary side and leave it where it can be seen.
Have the family let you know if it ever gets brighter than normal. Or
better yet, call a pro.