Honeywell Chronotherm III to Nest wiring

[ShannonB14]

I'm trying to replace a Honeywell Chronotherm III that has the following wires: R,Y,G,W,O,B

When I wired it to nest routing B to C the system only blew cool air. I have two zones in the house. Does that mean it's incompatible?

[Jenelyn_O]

Hi ShannonB14,

Thanks for reaching out. I'd like to take a closer look at it. Could you please take a photo of the wires connected to your heat pump control board? It will help us to further check the wiring configuration. Also, in what country are you located? 

To post a photo, click this link then scroll down to your response and hit reply. Check for the camera icon or click the three horizontal dots to expand the toolbar.

Best,

Jenelyn

[ShannonB14 · Accepted solution]

 

[zoeuvre]

Hi folks, 

@ShannonB14, chiming in—could you also share a photo of how you connected the thermostat wires to your Nest Thermostat base and a photo of how are the wires connected on your system's control board so I can take a closer look? 

I appreciate your help, Jenelyn.

Thanks,

Zoe

[ShannonB14]

R -> R

Y-> Y

G->G

W->W

O->OB*

B-C

It blew cold air. I changed the app setting as to which wire was the heat pump but it was still cold air. Put back on old thermostat and it worked fine again.

[zoeuvre]

Hi there, 

Thanks for letting us know. I can tell that you wired the thermostat wires correctly on the thermostat base, and I can tell that the Nest Thermostat is the one at fault after you reinstalled your previous thermostat and your system is working fine again. In this case, I recommend you reach out to the store where you bought the thermostat so they can have it replaced for you.

Regards,

Zoe

[ShannonB14]

Hmm... Not sure I believe that. I feel like it's because I have 3 zones. Open to other feedback.

[ShannonB14]

*2 zones