Nest Thermostat connection with only 2 wires from a honeywell???

[FrankR]

Can't seem to find out how to connect my new Nest Thermostat using my existing 2 wire system. I only have a Red Wire and a White wire that is hooked up to my honeywell thermostat that I want to replace. Any help???

[FredFlintsave]

You need to get the Nest Power Adapter that interfaces between the heating system and the thermostat as the thermostat needs power and this is normally done through a C wire which you don't have.  

[FrankR]

Fred, thank you! Would that power adapter be installed on the boiler? It is a 3 zone hot water system. Would I be putting the adapter on the zone opener??

[FredFlintsave]

The adapter has 5 wires and goes by the boiler, the W wire goes to the zone valve, two wires go to the transformer for power and the two go to the t-stat.  The book that comes with the adapter is very well written and has simple diagrams that show how to interface it.  I put velcro on the back and stuck it near the zone valves on the joist.  

[FrankR]

Thank you again Fred!!

[EdwardT]

Hi folks,

@Houptee and FredFlintsave, thanks for the help!

@FredFlintsave, how's it going with your Nest Thermostat? Still need our help?

Thanks,

Edward

[EdwardT]

Hi FredFlintsave,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[EdwardT]

Hi FredFlintsave,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[FrankR]

Hi Fred, decided to go with the GEN 3 NEST instead of the newest one out. The Gen 3 works with 2 wires. Just needed the RH (red wire) and the W (white wire) connection. Much easier to hook up, no C wire needed.

Frank

[Jake]

Hey there,

I am glad to hear you got your device set up. I wanted to check in with you, and see if you had any further questions from here. Please let me know, as I would be happy to take a closer look.

Best regards,

Jake

[Jake]

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake

[Houptee]

You can either pull new 5 conductor thermostat cables to each tstat and connect a real C wire.

Or get a power adapter but each zone/Nest will need its own adapter.

You need to know where the R+  and the - Common is on the boiler transformer to wire it correctly.