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Author Topic: New thermostat issues  (Read 134 times)

Offline aaron86

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New thermostat issues
« on: May 19, 2017, 11:54:52 PM »
Hi guys I bought a new touch screen thermostat and after installing it, it's not powering up.  I have a wire going to c in furnace electrical panel but does not come up to the thermostat.   The thermostat I have is a honeywell rth9580.  I have r going to r w (white)  going to w y (black) going to y. And g going to c.  Any help is well appreciated.

Offline Admin

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Re: New thermostat issues
« Reply #1 on: May 20, 2017, 06:43:38 AM »
You can sacrifice the fan control and use G, but you have to remove it from the G terminal in the furnace and connect it to C.  It sounds like you are connected from the furnace G to the thermostat C.

Buy the Honeywell THP9045 Wiring Module in order to keep the G fan control,

http://www.pexuniverse.com/docs/pdf/hw-69-2065-installation.pdf

Offline aaron86

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Re: New thermostat issues
« Reply #2 on: May 20, 2017, 01:39:50 PM »
Hi thanks for the reply.  Is there anything else I can do at the thermostat instead of changing wires at the furnace control?  As I have a wire coming from g and c it's confusing as to why the c wire did not make it up to the thermostat.

Offline walker

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Re: New thermostat issues
« Reply #3 on: May 20, 2017, 07:47:55 PM »
do you have 5 wires at the furnace and only 4 wires at the thermostat?  you need 5 wires at the thermostat to the furnace to make it work. otherwise like admin said you need the add-a-wire kit.

Offline Sergroum

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Re: New thermostat issues
« Reply #4 on: May 20, 2017, 11:22:15 PM »
If what you're saying is that you see one single wire coming from C, then odds are this wire is not going to your thermostat. Your Air Conditioner also has a wire going from Y and C to the contactor on your outside unit.  So if you have an air conditioner right now and see only one wire at your C terminal, then you do not have a C wire going to your thermostat.  Logic dictates, that if you have a C wire going to your thermostat and have an air conditioner at the time, you should have 'at least' two wires to your C terminal. Three, if you also have a humidifier.


Offline aaron86

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Re: New thermostat issues
« Reply #5 on: May 21, 2017, 12:46:37 PM »
Hey really appreciate the clarification, as this is new to me but have already started running new c wire.  Thanks guys!