Help Nest 3rd Gen Thermostat. All electric. Heat and Aux heat works, AC is blowing hot air.

[Aphuynh15]

Please help. I have all electric heat pump, air handler with AUX heat. Heat pump heating and AUX heat works fine. However, when using the heat pump for AC the system blows hot air.

I noticed the heat pump fan won’t change direction even after changing the settings of the OB wire on the Nest.

[Patrick_Caezza]

Post a picture of how the original thermostat was wired

[Aphuynh15]

I don’t know how to post photos here but the link below is my post on Reddit:

https://www.reddit.com/r/Nest/comments/tctlk0/help_nest_3rd_gen_thermostat_all_electric_heat/?utm_so...

[Patrick_Caezza]

Your thermostat wiring is straightforward.

Yellow - Y to Y1

Green - G to G

Blue - C to C

Orange - O/B to OB

White - W2 to W2

Red - R to Rc

When you change over to cooling from heating the blower doesn't change direction, it's the reversing valve in the outdoor evaporator the engages.

Try doing a factory reset to the thermostat and setting it up again.

Here is a little insight.

The Y terminal is what turns the heat/cooling on or off.

THe O/B terminal is what changes between heating and cooling.

You can test your system by connecting the Yellow, Green, and Red wires together. This should turn the system on and it will blow either hot or cool air. Add the orange wire to the group and it should blow the opposite of what it was blowing.

If it doesn't switch, then you have a problem with your system and not the Nest thermostat.

[Aphuynh15]

Thanks for the feedback to test I connect the Y, G, and R wires together at the thermostat or at the heat pump? Or does it not matter?

[Patrick_Caezza]

Connecting them together at the thermostat is the easyist.

[Aphuynh15]

Thank you so much for your help. I jumped the Y, G, R, and O wire at the thermostat and the AC worked! I am going to work on getting a replacement.

[MelbaDT]

Hey folks, 

Thanks for answering to this, Patrick_Caezza. 

Aphuynh15, glad to hear that you've found a temporary fix. I've also checked on the email address associated with your Community profile and I was able to see that a replacement was just recently processed for you. You'll receive it in a few days.

Feel free to reach out again should you have more questions. 

Best, 

Melba

[MelbaDT]

Hi, 

I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. Should you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.
 

Best, 

Melba