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Secondary C Terminal on Furnace Circuit Board?

  • Last Updated:
  • Oct 7th, 2019 10:02 am
[OP]
Member
Jun 2, 2007
414 posts
57 upvotes
Toronto

Secondary C Terminal on Furnace Circuit Board?

Hi guys,

I was trying to install an Ecobee thermostat, and there was no C wire installed. When I went to install the power extender kit, I saw the standard C wire terminal was broken out of the black plastic casing, and I couldn't attach the C wire. There appears to be a secondary C terminal that is a different style with a plastic plug plugged into it, and then the wire is spliced and connected to the wire heading to the AC unit. Can I add a second wire to this plastic plug, is this a secondary C terminal that should work fine? I attached a pic.

Thank you!
Images
  • c terminal.jpeg
4 replies
Sr. Member
Jan 19, 2013
543 posts
324 upvotes
Ottawa
Sounds good to me.
And plastic plug is called a wire nut btw
Deal Fanatic
User avatar
Oct 19, 2008
6646 posts
2252 upvotes
GTA
quick90 wrote: the wire is spliced and connected to the wire heading to the AC unit. Can I add a second wire to this plastic plug, is this a secondary C terminal that should work fine? I attached a pic.
Its hard to see from that pic, is that a wire from the marrette grounded to the furnace body?
[OP]
Member
Jun 2, 2007
414 posts
57 upvotes
Toronto
Zamboni wrote: Its hard to see from that pic, is that a wire from the marrette grounded to the furnace body?
Yes I believe it is, the white wire runs to the AC compressor.
Deal Addict
Jan 21, 2018
4665 posts
4718 upvotes
Vancouver
The "C" wire connects to the common terminal of your 24vac transformer. Find the transformer and trace the wires. You can connect a new C wire anywhere that's connected to that common terminal.

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