cancel
Showing results for 
Search instead for 
Did you mean: 

Nest wiring

Bz
Community Member

I have a two wire thermostat, red wire and White wire. I have 24 V on the red wire at my thermostat location. I understand the nest needs a C wire. And the C Wire is constant 24 V. Why can I not add a jumper wire from our to see at my thermostat location to give my device constant voltage on the C wire?

5 REPLIES 5

sporfrog
Silver Product Expert
Silver Product Expert

Generally speaking the common completes the circuit of 24v so it can be used to power the thermostat. The red wire in a two wire system is not a replacement for C (common). Having a C wire is recommended for a Nest thermostat. You might be able to get a Nest Learning thermostat to work in your situation.  Don't jumper R to C.

Bz
Community Member

Thanks for the fast reply I appreciate thatI have an old old system, two zones for the heater and the zones use relays. I don’t even have a circuitboard to create a C wire. I do have a two wire to the thermostats I was just trying to figure out how to give the nest device constant 24 V.

elcidny
Community Member

What is the "Nest learning thermostat"?

MelbaDT
Community Specialist
Community Specialist

Hey folks, 

 

Thanks for answering to this, sporfrog.

 

@Bz and @elcidny, I wanted to drop by to ensure that everything is covered here. Let us know if you have more questions, we're just here. 

 

Best, 

Melba