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Followed the wiring guide and it all works but won’t produce heat.

Community Member

Here is what my old wiring looked like on my previous thermostat. I followed the guide for where it said to hook everything up and now it’ll power up and show that it’s heating but it’s not

blowing out hot air  did I wire something wrong? Where should all of these wires have been placed in the nest?7AFC29A4-E002-4050-B7D7-9C5C160AC5DF.jpeg


Gold Product Expert
Gold Product Expert

Which model of Nest Learning Thermostat do you have? 1st, 2nd, 3rd gen? An EU model with a heat link?

Do you have a heat pump or a conventional system?

Do you have a dual-fuel system? (i.e., heat pump for primary heating/cooling, as well as a furnace)

Third gen. Just got it. I believe I have A heat pump (that’s what my ac unit says based on the model number). And that means I would have a dual fuel system?

So you have no gas, oil, propane etc for emergency heat? If you don't have a fuel system like that, you don't have a dual-fuel system. Looking at your wiring, I think you have a 2 stage heat pump with an auxiliary heat relay. Diagram below of the wiring for that.


Nest Thermostat doesn't use the wires labelled S1 and S2 so don't connect those. Nest Thermostat doesn't support jumper wires, so don't connect the jumper cable you see between E and AUX.

Does that match how you've wired it up?

Yes that’s how I had it wired and it is throwing our cold air when on heat. I switched the w2 to w1 and I get best sometimes but it isn’t consistently hot so at this point I’m lost and I don’t know what I did wrong. Maybe I have a setting wrong. But I have a furnace downstairs that I believe is gas (not propane) and a heat pump attached to my ac unit . 

Ah okay, so you do have a dual fuel system. In that case, wire it as follows:

  • Y - Y1
  • G - G
  • Rc - Rc
  • Y2 - Y2
  • OB - OB
  • C - C
  • E - E

If it still doesn't work, because you have a dual fuel system and Nest Thermostat doesn't support jumper wires, you're probably going to need to consult a local HVAC technician or a Nest Pro to make it compatible with your setup. What I said about the S1 and S2 wires still applies.

Community Specialist
Community Specialist

Hello folks,


I wanted to stop by and see how I could help.


Thanks for helping, @davidking.


@Austinpark1823, I found a helpful article with some troubleshooting steps for the heat pump system. Please take a look at this article and let us know if you need more help.




Community Specialist
Community Specialist

Hello everyone,

@Austinpark1823 how's it going with your Nest Thermostat? Were you able to read the information and check the link that Mark has shared? In case you have an update, you know where to find us.

I appreciate the help, davidking and Mark.

Community Specialist
Community Specialist

Hey Austinpark1823,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.