Nest error when switching to cooling.

[brwmstr]

Installed Nest and everything worked through the winter with heating.  Switched to cooling today and got the error message saying Wi-Fi not connected, install stable power source g.co/nest/m22.  The fan would not stop running.  When I manually switched back to heating mode, everything worked fine, connected to Wi-Fi, fam stopped.  What’s going on?

[CoolingWizard]

You description sounds like a software bug.  Have you checked for any needed software updates for the thermostat?

The AC Cooling Wizard

[brwmstr]

I just checked, it's up to date so no updates available.  Got a new code this morning though, said

"Connected to Y-W-G-R  Note:N262".

I'll have to look into that.  Weird that there were no problems until I switched to cooling.

[CoolingWizard]

Hmmm, that error is for a low battery and suggests adding a Common Wire.  Your Nest thermostat was installed without a common wire?

The AC Cooling Wizard

[brwmstr]

The battery indicator in the nest reads full. I guess it’s without a common wire.  I have a white, yellow, green and red.  Unless it’s one of those?  Could cooling need one but not heating?

[CoolingWizard]

What model Nest Thermostat are you using? 

The AC Cooling Wizard

[brwmstr]

It’s the Nest Thermostat, not the learning or “e” version.

[CoolingWizard]

Can you provide details on your equipment setup? That is type of heat and type of cooling. 

The AC Cooling Wizard

[Jenelyn_O]

Hi there,
 

Thanks for reaching out. I just want to check if you were able to see CoolingWizard's reply. Could you please provide information on your equipment setup? It will help us to move forward. Also, you can visit this support article to get more information about the code N262 you received.
 

I appreciate your help, @CoolingWizard.
 

Best,

Jenelyn

[msofia531]

Based on Cooling Wizard's recommendation, I moved the Power Connector wire (intended to go to the Y (cooling) terminal) to the W terminal (heating terminal).  So now my AC works without the "low power" message and I think/hope it will no longer drop the Wifi.  But this fix will require me to move the Power Connector wire back and forth at the Furnace's Control Board from W in the summer to Y in the fall so I won't have issues running my heat in the winter.  Google Nest should have a better, permanent fix than this.  SO WHAT IS GOOGLE NEST EXPERTS' FIX ? 

[brwmstr]

Sorry.  It’s a forced air unit.  I think I ended up needed the power adapter thing from Nest.

[Jenelyn_O]

Hey brwmstr,

Thanks for a quick update. Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough consistent power. If your Nest Thermostat detects that it didn't receive sufficient power, you may need to connect a common wire (C wire) or Nest Power Connector.

Regards,

Jenelyn

[CoolingWizard]

You should know that the nest thermostats have a pretty advanced electrical/electronic design. The power required to use the charging circuit to charge the batteries or maintain the system. Operating are very low current requirements. Now some of the older type HVAC systems don’t use an advanced control board. In those cases, the nest can look for the coil on the relay for the air conditioner or the furnace gas valve controller. Now if it can find the common, it can draw a little bit of current over that wire to charge the system battery or maintain the system operation. When you hook up a nest thermostat with the R wire, a W wire, Y wire, G wire, you can see if indeed, the thermostat can find what it’s looking for. If it cannot locate the common side because of a more advanced control board for example, then you will get an an error message.

The AC Cooling Wizard

[zoeuvre]

Hi brwmstr,

I wanted to check and see if you managed to see the information that Jenelyn and CoolingWizard has shared. Please let me know if you have any questions from here. I would be happy to assist and make sure you are good to go.

Thanks for your help, @CoolingWizard and Jenelyn. 

Best, 

Zoe

[msofia531]

Zoeuvre,  Can you help me:   I have the exact same problem as Brwmstr .  I installed a Nest Thermostat which also needed a Nest Power Connector and I had no problems with heat all winter.  Now, I turn on the AC and I get the same messages as he did:  "Wi-Fi not connected, install stable power source g.co/nest/m22."  However, my AC appears to be running normally (fan shuts off) but I have the above messages.  How do I fix it?

[msofia531]

Based on Cooling Wizard's recommendation, I moved the Power Connector wire (intended to go to the Y (cooling) terminal) to the W terminal (heating terminal).  So now my AC works without the "low power" message and I think/hope it will no longer drop the Wifi.  But this fix will require me to move the Power Connector wire back and forth at the Furnace's Control Board from W in the summer to Y in the fall so I won't have issues running my heat in the winter.  Google Nest should have a better, permanent fix than this.  SO WHAT IS GOOGLE NEST EXPERTS' FIX ? 

[msofia531]

Cooling Wizard,  Can you help me?  I have the exact same problem as Brwmstr .  I installed a Nest Thermostat which also needed a Nest Power Connector and I had no problems with heat all winter.  Now, I turn on the AC and I get the same messages as he did:  "Wi-Fi not connected, install stable power source g.co/nest/m22."  However, my AC appears to be running normally although I have the above messages.  How do I fix it?

[Jeran]

Hey there brwmstr,

Do you have any more questions that we can address? 

Thank you,
Jeran

[zoeuvre]

Hello there, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you run into any more issues in the future, please feel free to create a new thread.
 

All the best,

Zoe 

[msofia531]

Jeran,  Can you help me:   I have the exact same problem as Brwmstr .  I installed a Nest Thermostat which also needed a Nest Power Connector and I had no problems with heat all winter.  Now, I turn on the AC and I get the same messages as he did:  "Wi-Fi not connected, install stable power source g.co/nest/m22."  However, my AC appears to be running normally (fan shuts off) but I have the above messages.  How do I fix it?

[msofia531]

I have the exact same problem.  I installed a Nest Thermostat which also needed a Nest Power Connector and I had no problems with heat all winter.  Now, I turn on the AC and I get the same messages as you.  Wi-Fi not connected, install stable power source g.co/nest/m22.  However, my AC appears to be running normally although I have the above messages.  How do I fix it?

[CoolingWizard]

@msofia531 , @brwmstr ,
The Nest power connector uses either the W wire or the Y wire to bring the 24Vac common back to the thermostat.  You must have wired the Y wire to the Nest Power Connector.  When your Nest system Mode is set to cooling and is actively cooling, the Y wire is not available for carrying the 24Vac Common. Once the cooling temperature set point is attained and the thermostat will terminate the Y and R wire connection, The Y wire will then be available to carry the 24Vac Common again. 
Personally I wish  the Nest power connector had both a separate Y and W wire connection..  In this way the Power Connector can be connected to both the Y and the W and use the path not being used by the current system mode.  Otherwise, It might require a homeowner to perform rehoming of the W and the Y wires at the power connector each seasonal change.  

AC Cooling Wizard

[msofia531]

Wow.  Thank you.  After I read your response twice and opened the Power Connector installation booklet, I could understand what you were saying.  Yes, according to the booklet, I did connect the YW Connector wire to the Y.  Is there another way to do this so the connector works with both heating and cooling?

Also, I have attached a photo of my thermostat wiring.  Should I have a wire connected to the C terminal? 

Currently, as you can see, I do not.  

[CoolingWizard]

You need to trim all those bare copper conductors.  When you update the software of the Nest Display, it will recognize the power adapter.  What you can do is rewire the power connector by using the W wire.  If your a furnace uses a control board with a heat relay, it will be able to reach the 24Vac Common. 

AC Cooling Wizard

[msofia531]

Thanks.  I moved the Power Connector wire to the W terminal at the control board like you, and others, suggested.  I am interested in a permanent fix so I dont have to change the wire back and forth every 6 months.  I know I could try and run a new thermostat wire (which I would probably mess up) or I could move the G wire to the C terminal at the furnace and at the thermostat but any other permanent solutions you could suggest?

Again thanks for your help.

Mark

[CoolingWizard]

When you have a furnace, the fan control is generally automatic.  However, when in cooling mode, the fan blower motor is generally activated by the thermostat.  You need to run a test.  Remove the G wire from the nest backplate. Then, run a cooling and heating test and see if the Furnace control board automatically controls the blower in both system modes.  Typically about 2 minutes after the compressor or furnace is started the blower fan should start up. As I said, it is the cooling mode that is questionable.  

AC Cooling Wizard

[msofia531]

Hmm, So, if the blower comes on automatically in cooling mode then I can switch the G wire to the C terminal at the furnace and to the C terminal at the Nest thermostat?  Is that what you are getting at?

And also if the fan works, then I  can just disconnect the Nest Power Connector because it would no longer be needed.  Do you agree?

[zoeuvre]

Hi msofia531, 

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

You don't have to switch any wires. Since cooling is what is in question, you just have to first turn off the power to your thermostat. Remove the G wire from the Nest backplate. Check the furnace control board's ability to manage the blower automatically in both system modes by performing a cooling and heating test. The blower fan ought to turn on approximately two minutes after the compressor or furnace is turned on. After that, let us know how it goes.

Thanks for your help, @CoolingWizard. 

Best,

Zoe

[zoeuvre]

Hi folks,

@msofia531, I wanted to check and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.
 

Thanks,

Zoe

[zoeuvre]

Hello there, 

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. 
 

Regards,

Zoe