Nest 4th gen won't allow to configure star * terminal as W3 terminal

[matick]

Hello,

I am trying to configure my convetional heating system with 3 stages. I connected C, Rh, W1, W2 and star *. During setup I cannot configure * terminal as W3 terminal. See attached images. 

My old 3rd gen Nest didn't have any issues. 

Help appreciated!

[CoolingWizard]

@matick , I am curious to know how long is your thermostat cable between the thermostat and your air handler? I noticed you have a white with a green tracer and a white with a orange tracer 22 gauge telephone wire being used in this thermostat. 

AC Cooling Wizard

[matick]

It’s just a signal wire for PAC-444 interface. But this is not the issue here 😉

i am pretty sure W3 stage is not configurable on Nest 4th gen due to some software bug. 

[SoriaD_]

Hello @matick 

Thanks for reaching out to our Nest Community. We apologize for all the inconvenience with this new installation. Don't worry, I'm here to help you with the stage 3 cooling on your Nest Learning Thermostat.

To better assist you, let me ask you for more details about your HVAC system.

• Could you tell me what the delivery type of your HVAC system is?
• What is the heat fuel source?
• Additionally, you can share a picture of the previous wiring configuration or your dashboard.

With these details, we can find an answer for this situation.

Feel free to keep us posting.

Best regards,

Douglas.

[matick]

@SoriaD_ 

The delivery type is Forced air, electric.

Pictures are in the first post. It is the simples possible configuration. W1,W2,W3 and Rh and C. In the manual it says the Nest 4th gen is compatible with 3 stage heating. Wizzard won't allow to configure * as W3 wire. 

[CoolingWizard]

@matick , sometimes the first heatvstage is Heat Pump, second is Gas 1, and third is gas 2. There is no gas furnace that has three heat stages that I am aware of. 

You say your system will is forced air however you hooked up no G wire. 

AC Cooling Wizard

[matick]

In my case. First stage W1 is underfloor heating. W2 and W3 are connected to PAC W1 and W2. But new Nest 4th gen won't allow me to configure it as 3 stage system. So i simplifed this and presented it here as simple 3 stage system. Still no answer from Google. Why can't i configure it as a 3 stage system?

@CoolingWizard Thanks for your valuable input! 🙂 But i think google needs to step in and explain why 4th gent cannot be configured as simple 3 stage heating system! 

[CoolingWizard]

You said you are using a PAC-444 interface to your Mitsubishi indoor unit correct? That unit does not have 3-stages of heat. It does support 3 fan speeds (G1,G2,G3); 2 heat stages (W1, W2); 2 cooling stages (Y1, Y2).  You are wanting 3-speeds of fan. G1, G2, and G3. However, it is far more efficient to leave the PAC-444 fan speed in the AUTO mode. So do not connect the G wire to the PAC-444.

AC Cooling Wizard

AC Cooling Wizard 

[matick]

I have it set to auto yes. PAC will ignore G wire when heating/cooling. But i can still run ventilation when i want it if i leave it connected. 

[CoolingWizard]

Show me a picture of your old thermostat and its wiring so see how it controls all three and perhaps we can figure out a way to make it work for you. 

AC Cooling Wizard

[matick]

@CoolingWizard The first picture is how it was configured with my old Nest 3rd gen thermostat. The second picture is how I would like to have it with the 4th gen thermostat. 

This is from their manual and the wizzard inside Google home app will not allow me to configure star terminal as W3 stage 3 heat. (see my first post).

I simplifed it for support to include just 3 stages of heating. But wizzard still won't allow me to configure star terminal. 

 

 

[matick]

@SoriaD_ Any suggestions? Why I cant configure * for stage W3 heat? Maybe a bug in Google home app?

[SoriaD_]

Hello @matick 

Thanks for your reply and all the information you provided me. 

I have shared this case with my specialized team, who recommends that you contact them so that they can assist you in a live manner and determine the reason for this situation.

Please fill out this form to contact our support, and our specialist will do it all to find a solution. 

Feel free to keep us posting. 

Kind regards,

Douglas.

[matick]

@SoriaD_  I don't want to be beta tester for unfinished products. I replaced it wih the Nest 3rd gen thermostat which is working as advertised. My next thermostat will probably be Ecobee. Google doesn't care about thermostats anymore. And 4th gen is a disaster.