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I have an older furnace, on the switch block I have Y,C.W,R and an unlabeled screw that connects to the shut off it looks like. I need to hook up a thermostat that needs the C wire. I have a spare wire, in the bundle which I hooked up to the c terminal downstairs, from these videos that I've seen it tells me to then bridge the Y and G together, I do not have a G on the block, what do I need to do to get the neutral wire set up

Tester101
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Brian Miller
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  • Forgot to add that I have gas heat only – Brian Miller Mar 07 '13 at 17:07
  • What is the make and model of the furnace? – Tester101 Mar 07 '13 at 17:27
  • After more testing I discovered even though its a c wire, it's not pulling 24v, so I'll need to add another 24v to the one wire – Brian Miller Mar 07 '13 at 17:32
  • It's only a C wire, if it's attached to the C terminals at both ends. It sounds like you're not sure what you're doing, you might want to contact a local HVAC technician before you fry your furnace. – Tester101 Mar 07 '13 at 17:37
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    This answer might be helpful. – Tester101 Mar 07 '13 at 18:26
  • I spoke with honeywell (thermostat), the issue I was having was the thermostat was resetting, while on the phone we found out that the c wire had 0 voltage, and the thermostat as actually pulling the 24v from the rh wire. So I went ou and bought a 24vac power supply to give the thermostat the voltage it needs – Brian Miller Mar 07 '13 at 20:35
  • You should only have 24VAC between Rh or Rc and C - C is the neutral and works as a return so the thermostat can be powered without powering any of the other relays – Steven Mar 07 '13 at 21:25
  • It's a z wave/wifi thermostat, which requires 24v to rh/rc and the common needs power as well to power the z wave. – Brian Miller Mar 07 '13 at 21:41

1 Answers1

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You have a C wire, so use it - you don't have to bridge as that is only necessary if you don't have a spare wire.

Steven
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