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Honeywell Wi-Fi Thermostat Installation (Goodman Furnace) - C Wire Help

Honeywell Wi-Fi Thermostat Installation (Goodman Furnace) - C Wire Help


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Old 03-25-15, 11:06 AM
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Honeywell Wi-Fi Thermostat Installation (Goodman Furnace) - C Wire Help

I want to replace my current Honeywell # RTH2300B programmable thermostat (at both Zones) with Honeywell Wi-Fi thermostat # RTH6580WF (one zone) and Nest (second zone).

I have Goodman furnace GMS91155DXA with Honeywell MiniZone 2 zone system and current wiring is as below.

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@Air handler:
Y & C - going to Outdoor AC Unit
Y, G, W R - going to Thermostate

@Thermostat:
Y, G, W, R - coming from Air Handler and used in old thermostat
2 extra wires (blue/ orange) - Not connected anywhere

I have 2 additional wires at thermostat which are not being used in my current thermostat. I opened up Air handler and found they are connected to some wires going to transformer using wire nut. Can I disconnect any of those blue/ orange wire from wire nut (they are going to thermostat and not used) and connect to 'C' wire?

I want to connect any of those blue/ orange to C wire below. My current C terminal has also C wire going to my outdoor AC unit.
 
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Old 03-25-15, 05:03 PM
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That looks like some kind of old DIY hack job. The ground wire isn't connected and the transformer isn't even secured. The primary side is still connected so are you sure the blue and orange wires aren't connected to something at the other end?

If not then my guess is that it was used as a 24volt power source for another thermostat that was changed out.

But if you're sure they're not being used then go ahead and disconnect and use the wires for your new install. I would disconnect and remove that transformer though as it doesn't look like it needs to be there.
 
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Old 03-25-15, 09:11 PM
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Many zone control boards require a separate transformer to power the dampers.

It is odd to see a ground wire on a transformer.

I would expect to connect the thermostats to the zone control board. What is the model number of the zone control board?
 
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Old 03-26-15, 03:55 AM
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Many zone control boards require a separate transformer to power the dampers.
Yeah, but he said the wires appear to be dead ending at the thermostat, and that transformer clearly was not installed by an hvac tech. It appears to be an 'after market' idea.
 
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Old 03-26-15, 04:35 AM
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It should be rechecked before removing the transformer.
 
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Old 03-28-15, 09:19 AM
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C Wire help

As per below given Images, those additional wires (Blue/ Orange) at thermostat are only connected to wire nut with Blue/ Yellow wires on the other side and those Blue/ Yellow are not connected to anything else.

I have Honeywell Minizone 2 Zone controller system. I think I will try to remove the thin Blue wire wirenut and try to connect to 'C' terminal at Air handler and other end to 'C' terminal of thermostat and see.

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Old 03-28-15, 09:26 AM
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Could that transformer have been for a humidifier ?
 
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Old 03-28-15, 09:47 AM
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I don't have any humidifier right now.
 
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Old 03-28-15, 11:50 AM
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That transformer appears not to be doing anything... other than not being up to code and causing a possible safety hazard. My pure guess is that it USED to be powering a thermostat at one point, but either way you should either remove it or properly secure it.
 
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Old 03-28-15, 02:50 PM
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That transformer appears to be connected to two wires that run off of the picture to the lower left.

I would not recommend removing any components unless we see the other end of those 2 wires. It would be bad advice to recommend removing that transformer at this point. Very bad.:NO NO NO:
 
 

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