enter image description hereenter image description hereenter image description hereI am trying to add a wireless thermostat for my parents. I've put several in, but this one I have an issue I have not been able to google for an answer. They have a new combo unit. I need to add a c wire for the thermostat. The unit is all electric. There is currently an unused blue wire at the thermostat and at the unit. My issue is at the unit, there is no terminal strip. There are 2 brown common wires wired together, and the red, white, yellow and green are all together individually. I tried wiring the blue wire to the brown common wires, but that didn't work. Where can I wire that blue wire so I can get the 24 volts that I need to run the thermostat. It would be simple if there was a terminal strip like normal. Thanks for any help

  • Can you post photos of the wiring at the unit? – ThreePhaseEel Mar 19 '17 at 4:57
  • Can you find the transformer? Can you distinguish the 24V side of the transformer? – Harper - Reinstate Monica Mar 19 '17 at 5:29
  • Yes I know where the 24v transformer is. Can I wire to it direct? – JV71 Mar 19 '17 at 17:00
  • I attached a couple of pics – JV71 Mar 19 '17 at 17:42
  • Did you ever get this resolved? If so, please give a check-mark to the answer or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer. – FreeMan Aug 20 at 16:17

I can’t quite tell by the pictures but if you look at the transformer you see a red wire and then a green and a brown wire. Trace the red thermostat wire back to the transformer. The other wire is the common. If the red on the transformer goes all the way to the red thermostat wire then the brown and the green are common.

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