topic Re: Heat Pump not heating in Nest Thermostats

Heat Pump not heating

Jerandlaur — Fri, 31 Oct 2025 14:24:48 GMT

I have a heat pump and just installed the Nest 4. I wired the heat according to the picture form my old thermostat and I can’t get heat. Emergency heat works but not regular heat.

I can’t figure out how to post pictures here but everything is the same. Would appreciate any help.

Re: Heat Pump not heating

Patrick_Caezza — Sat, 01 Nov 2025 03:15:36 GMT

@Jerandlaur

Post a picture of the original thermostat's wiring

Re: Heat Pump not heating

Jerandlaur — Sat, 01 Nov 2025 05:15:10 GMT

@Patrick_Caezza i don’t see how to pair a picture. There is no way to insert one.

Re: Heat Pump not heating

Patrick_Caezza — Sat, 01 Nov 2025 06:59:31 GMT

@Jerandlaur

If you created an account, you should see this.

Re: Heat Pump not heating

Jerandlaur — Sat, 01 Nov 2025 16:46:08 GMT

Thank you. I have posted the original writing and how I have it wired now. In the app I switched form “O” to “B” as was recommended but since they are the same wire I didn’t think that would do anything. The compressor kicks but is blowing cold air.

Re: Heat Pump not heating

Jerandlaur — Sun, 02 Nov 2025 09:46:27 GMT

@Patrick_Caezza

oops, forgot to tag you. The pictures are above.

Re: Heat Pump not heating

Jerandlaur — Tue, 04 Nov 2025 02:12:21 GMT

@Patrick_Caezza @Can you help?

Re: Heat Pump not heating

Patrick_Caezza — Sat, 08 Nov 2025 04:55:16 GMT

@Jerandlaur

The only recommendation I can offer is to move the white wire from W1 to W2/Aux and set it as Aux heat.

If that doesn't work, try taking the yellow, red, and green wires and connect them together. This will activate the system, and it should blow cool air. Add the orange with it, and it should blow heat.

If it still only blows cool air, then your system probably has an issue.

Re: Heat Pump not heating

Jerandlaur — Sat, 08 Nov 2025 14:29:19 GMT

@Patrick_Caezza Emergency heat works just not regular heat. The compressor kicks on but won’t heat. Will changing W1 to W2 help that? Potentially?

Re: Heat Pump not heating

Patrick_Caezza — Wed, 12 Nov 2025 05:14:22 GMT

@Jerandlaur

Check what you identified each wire as. I don't see any wiring that would provide you with emergency heat.

It looks like you have a 1-stage heat and cooling heat pump with auxiliary heat, based on the wiring I see.