topic Re: Nest 4 th generation w1 w2 serup in Home Automation

Nest 4 th generation w1 w2 serup

West31 — Tue, 09 Sep 2025 21:35:09 GMT

I replaced my gen 2 nest thermostat with a new gen 4. However my gen 2 had a w1 and w2 wire hooked up. This is for my heat pump and w2 controls stage 2 for heating. However my new gen 4 will not let me use both w1 and w2 wires. It says I must remove one. I didn’t hook the w2 wire however how will my stage 2 heat pump go on?

Re: Nest 4 th generation w1 w2 serup

EduardoN — Fri, 12 Sep 2025 22:52:43 GMT

Hi @West31,

Thanks for contacting this community! I understand what you're experiencing. You've recently upgraded from a Nest Learning Thermostat (2nd gen) to a 4th-gen model. You're noting that while your previous thermostat used the W1 and W2 wires for two-stage heating, the new thermostat won't let you use the two-stage heating. No worries, I'm here to help you!

At this moment, let me share with you that the newest Nest Learning Thermostat (4th gen) is also capable of supporting a two-stage heating system, because we can use more complex systems. For reference, you can check out this article: Learn about multistage heating and cooling system.

For that situation with your new thermostat, I'd like to ask you some questions:

Do you see an error code when you try to use the two-stage heating in the thermostat display or in the Google Home app?
Could you send me a photo of the wiring in the new thermostat?
In some cases, some systems are not compatible with certain Nest Learning Thermostats, depending on the generation. Because of this, what is the make and model of your HVAC system?

Please feel free to share any additional details you think might be relevant.

Best regards,
Eduardo

Re: Nest 4 th generation w1 w2 serup

West31 — Fri, 12 Sep 2025 23:29:42 GMT

Did you get my reply?

Just when I try to attach the w2 for the nest 4 it says equipment error. E413

When I don't hook it up the system will run but how do I know it will turn the 2nd stage heat on when needed?

Model Amana. AMST36CU1300. AIR HANDLER

Model 15.2 SEER2HP

Re: Nest 4 th generation w1 w2 serup

West31 — Fri, 12 Sep 2025 23:32:10 GMT

4th gen2nd gen

Re: Nest 4 th generation w1 w2 serup

EduardoN — Sat, 13 Sep 2025 23:26:01 GMT

Hi @West31,

Thank you for all the information you've provided. Regarding what you've been experiencing, the thermostat is showing an E413 error when you connect the W2 wire. This error appears because the thermostat detects a heat pump but requires a Y wire. However, in this case, we've already confirmed that you do have both a heat pump system and a Y wire.

Therefore, I'd like to provide some recommendations that you should check:

Check the thermostat wires:
- Remove the thermostat display.
- Check that the wires are in the correct terminals.
- Check that each wire has ⅜ inch (9.5 mm) of exposed wire.
- Check that each wire is properly seated.
- Turn on the power to the system, and check if the thermostat works.
Check if your system provide the correct power to your thermostat.

Keep me posted.

Best regards,
Eduardo

Re: Nest 4 th generation w1 w2 serup

West31 — Sun, 14 Sep 2025 00:10:32 GMT

Its still doesn't let me connect the w2 wire says the same error. I only have one y1 wire connected and nothing in the y2 spot. This is the same wiring as my nest 2 that was set up however i bought a new furnace and air conditioner. I was reading on one of your sites and it said you could insert the w2 wire in the * section.

Here is what it said The nest thermostat E supports one stage heating and one stage cooling and a second stage heating and cooling. You'll need to manually set the * or ob connector as your 2nd stage in the Equipment menu.

Then below that line it talks about the Learning Thermostat (4th gen) supports 4 stages of heating, consisting of 2 stages of heat pump heating and 2 stages of alternate heating.

So my question to you is even though this isn't the E thermostat. Can I just put the w2 wire in the * connector as my 2nd stage??

Anyway you can call me?

Thanks,

Bob

Re: Nest 4 th generation w1 w2 serup

EduardoN — Sun, 14 Sep 2025 00:53:43 GMT

Hi @West31,

Based on the explanation, the thermostat doesn't directly recognize the information from the W2 wire. For this reason, even though our thermostat is designed to use multiple stages for heating or cooling systems, it's often possible to use the * terminal for this system so it works in the most appropriate way, allowing you to have a more complete system.

For this type of installation, the most recommended option is to contact a Nest Pro. That way, you can get the appropriate assistance and avoid any potential damage to your system or thermostat.

Keep me posted.

Best regards,
Eduardo

Re: Nest 4 th generation w1 w2 serup

Venkyp — Wed, 07 Jan 2026 23:29:09 GMT

I have the same issue so I must now disconnect, replace this 4 th gen with my old 2nd, engage a Nest Pro for such a do-it-yourself situation? Seems like Nest does have a usability and customer problem!

Re: Nest 4 th generation w1 w2 serup

Venkyp — Wed, 07 Jan 2026 23:31:11 GMT

what happens if I disconnect W2 and run the system?