topic Re: O and B wiring help please! 😬 in Nest Thermostats

O and B wiring help please! 😬

CO_AZ — Mon, 06 Nov 2023 00:08:27 GMT

Trying to help set up my grandma's Nest in AZ and running into trouble. Old thermostat has O,B,W,G,RH wires. I tried connecting B to the C and the O to the O/B as others had success with. I received an error from Nest looking for the Y and moved the W to the Y. When we turned it on, instead of AC it was blowing heat. Help!!

Re: O and B wiring help please! 😬

CO_AZ — Mon, 06 Nov 2023 01:24:35 GMT

Nest tech help had me rewire back the W to original place. But then received the error code E77 looking for a Y1 wire. I contacted support again and they stated I need to have a dedicated Y wire added. It's there an easy fix to this without calling a specialist?

Re: O and B wiring help please! 😬

Subiewrx22 — Mon, 06 Nov 2023 09:43:45 GMT

Do you have a picture? Also do you have a yellow wire.

Re: O and B wiring help please! 😬

CO_AZ — Mon, 06 Nov 2023 16:04:17 GMT

I do have a yellow wire and a picture: https://photos.app.goo.gl/VoFm8sjPH8QFnEhL9

It is a heat pump system. I've also tried moving the yellow wire to Y but when turning on the AC all we had was the fan and no cooling.

Re: O and B wiring help please! 😬

Subiewrx22 — Mon, 06 Nov 2023 17:10:05 GMT

Here is my wiring.https://photos.app.goo.gl/JiainJqUwfccshto7

Re: O and B wiring help please! 😬

zoeuvre — Thu, 09 Nov 2023 14:58:15 GMT

Hi folks,

Thanks for chiming in, @CO_AZ.

@Subiewrx22, oh no! Let's see what's going on.

Are you located in North America or Europe? What type of Nest Thermostat do you have? Since you have a heat pump heating system, your thermostat wires should be wired as follows:

Yellow wire to W or W1
Green wire to G
White wire to OB or *OB
Blue wire to C
Red wire to R or RH

Let us know how it goes.

Best,

Zoe