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no power to thermostat, quick response greatly appreciated!

474 Views 6 Replies 3 Participants Last post by  wengang1
Hi all.

I took the thermostat apart to put up a new sheet of drywall, and then reassembled it. I took a video of it to make sure it went back together correctly.
Now there is no power to the thermostat.
No breakers flipped.

There are 9 slots in the thermostat, labeled: E AUX Y G O L R B C.
E and AUX had a black wire shunted across them. AUX had a white wire connected to it. Y had a yellow wire. O and L were empty. R had a red wire, B had a blue wire, and C had a copper wire connected to it.

I have 6 wires here, and not knowing what they all did, I tested all 30 possibilities with my tester and got no response.

I don't think I was rough with the wires in this process, but I did press them in a couple of times to get the thermostat case to close. It shouldn't have been enough to snap a wire of that thickness.

Now that I think about it, I did kind of swirl the wires together to push them through the wall. Something shorted out? Again, no breakers flipped.

What have I done wrong and what do I do now?

PS The urgency is that I have on A/C til I resolve this.
1 - 1 of 7 Posts
Make sure the fuse didn't blow again, then check the voltage at the t-stat between the C and R terminals. If you have 24V there your thermostat wiring or your thermostat is bad. If you don't have voltage there your board may be bad or your wiring may be bad.
You can start at the furnace and check the voltage where the wires connect first to see if there is power there.
1 - 1 of 7 Posts
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