Nest Thermostat Not Heating Without R/RC Jumper

[Athanatos]

I have a heat pump system. My old Honeywell thermostat has a jumper between R and RC. All things say it is compatible and that there is an "internal jumper" so you would just connect the R (red wire) in the R slot. This is not working for me and is causing cold air to blow when the heat is on. Reconnecting my old thermostat that has this jumper is providing heat. The A/C works fine, so there is no issue with my O/B setup (though I did troubleshoot this first by switching it to B with no luck.) My old thermostat was not using a C wire, but I did install it for the Nest. The only difference in wiring is adding the C wire and not having a jumper.

Pictured is the WORKING setup with the old thermostat.

Is there any hope for me or is Google incorrect in saying I don't need a jumper for the 2020 model?

[Markjosephp]

Hello Athanatos,

I'm sorry for the trouble this may have caused you — let's see what's going on.

Nest Thermostats don’t use jumper wires, and I appreciate you running some diagnostic tests on your thermostat. Going over these steps might help:

1. On the home app's homepage. Select your thermostat icon.
2. Go to Settings > Thermostat > Wiring.
   1. You can check your thermostat's wiring configuration.
   2. Check that all of the wires visible are installed in the same manner as they were on the base.
3. If so, try resetting the thermostat to its default setting.
4. Proceed by adding the device.
5. Ensure to select these wires during the set-up process: W/W1, Y/Y1, G/G1, R, and O/B.
6. Once finished, activate cooling and heating.

Please let me know if that helps, or if the issue still persists.

Best regarfs,

Mark

[Athanatos]

Hi there and thanks for replying.

I've already done everything possible for troubleshooting and spoken with many levels of Nest support. All attempts have been futile and they suggested everything was wired correctly and assumed there was something wrong with the O/B terminal on the Nest. I know there is nothing wrong with the device and there must be a compatibility issue somewhere because I have an Amazon Smart thermostat that has the same issue. I've decided not to hassle with it any further and am returning it. It seems I have to stick with my old battery-operated Honeywell thermostats.

Thanks for your efforts!

[Markjosephp]

Hi there,

I'm sorry if you have to go through this, and we'd like you to have a better experience using the Nest Thermostat.

It's possible that the issue is due to the wiring configuration or voltage output of your system. It can be rewired if needed with the help of HVAC technicians. So I'm going to lock this thread in 24 hours. If you ever change your mind and need more help, don't hesitate to give us a shout — we're always here.

Thanks,

Mark