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Thread: No power to "c" wire

  1. #1
    Junior Member

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    No power to "c" wire

    New to the forum, thanks for having me. After a year of use with my nest I am now finding the need to a "c" wire to my boiler relay. I have a multi zone argo control panel with a C terminal. I had an electrician come yesterday who ran a new single line directly from the nest to the argo box. I am still getting " No power to C" error code on the nest. Any ideas? The control is an argo arm-3p. Currently I have the wire going from the "C" terminal in the nest to the 24vac terminal at the common.
    Thanks.

    Last edited by Tacquavella; 01-11-2014 at 08:29 AM.

  2. #2
    HVAC Thermostat Specialist

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    After the C wire was connected did the electrician check the voltage between the Nest RH and C?

  3. #3
    Junior Member

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    No he did not. He seemed confused on how to wire the c connection. On the argo controller the rh and the w are wired into a zone with no free terminals. The common and the 24vac are on the far side of the control. He has the c wire by itself wired into the 24vac terminal. Am I correct in assuming the RH need to go in the common terminal next to the 24vac? The picture below is the same control (not mine but the same).

    Click image for larger version. 

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  4. #4
    Member

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    I see nothing connected at the C terminal.

  5. #5
    Junior Member

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    Sorry if I was not clear. The picture is the same control I have but not mine. It's just a google picture. The electrician used the terminal marked 24vac to connect the c wire. He also tried the terminal above it marked common. The rh and W wires are in zone 1. I appreciate your help. This is getting frustrating.

  6. #6
    HVAC Thermostat Specialist

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    Nest C = common
    Nest RH = 24vac

    Your Nest must have been receiving 24vac from the zone terminal in order for it to have been working before.

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