On Sat, 23 Jun 2007 19:17:41 -0700, Big_Jake
wrote:

On Jun 23, 8:48 pm, wrote:
if you have a circuit board in your ac/furnace. it may have blew a
circuit. it will look like a burn place on the cuircuit board.

http://www.minibite.com/america/malone.htm

I'm thinking the same, but more accurately, it is a 3A fuse. Your
furnace might have even come with a spare. Otherwise you might be
able to get one at an auto parts store or maybe Radio Shack. Don't
put in a bigger one!

House breakers are much much bigger than the amount of current used
internally to control things. For that there are glass fuses, or
maybe some other kind of small fuse.

When this happened when I was working on my friend's, there was a
spare fuse taped close to where the original fuse went. You dind't
give the brand of your AC, only the thermostat. It's the AC that
determines the fuse size, and when you find where the fuse goes,
somewhere near there it will say what size fuse to use. Perhaps on a
diagram, or on the circuit board, certainly someplace in the AC and
certainly also in the owners manual that came with the AC. IN my
friend's case, he had half of the AC ownners manual in his files, and
there was a second half stuffed in the condensor cabinet outside, that
the installer never took out and gave him. (Is that typical? They
leave it there for the repairmen?) I think both halves said what size
fuse to use, and one or both halves had a drawing that indicated where
the fuse went.

In that case, I blew the fuse by letting the control wires to the
condensor outside touch each other, but if you got sparks at the
thermostat, they are probably smart enough to make it blow a fuse,
probably the same fuse.

Next time, turn it off before moving wires, OK? And turn it off
before you replace the fuse, too. If not, you won't kill yourself, (I
don't think. ) but you might blow the second one.

JK