Nest Thermostat will not power orange wire to heat pump

[macair42]

I am a mechanical contractor with over 30 years of experience in the HVAC and electrical business.  My customer has a Nest Learning thermostat approximately one year old.  It worked normally in the heating mode but when customer switched to cool mode last week, the cooling mode did not work.  The problem is the Nest is not sending a valid voltage through the orange wire to the heat pump.  I disconnected the orange wires at the air handler and read 19 volts orange to common (red common was 26 volts and when i connected the two orange wires, the voltage orange to common dropped to zero.  The orange wire at the thermostat has a good connection.  The problem appears to be an internal one with the thermostat.  I would appreciate the assistance of one of your technical experts, please.

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[Houptee]

Did you try going into settings for the O/B wire output?

You can change it to output power in heat or in cool mode on the O/B wire.

[macair42]

I did reverse the O/B wire selection but neither produced 24 volts on the orange wire.  Since I am working with a Carrier heat pump, the reversing valve solenoid is powered in the cool mode.  The orange wire from thermostat to heat pump has continuity.  I have reached the opinion that the Nest is not powering orange wire in cooling mode.  I have been unable to talk to a live tech support Nest person.  Will not be recommending this product to customers.  Thanks for your response and please let me know if you think of something else I should try.

[Houptee]

@Markjosephp can you assist with this issue?

Thanks,

Houptee

[hitecmal]

i'm having the same problem however and the one i'm working on is also a carrier ...i've checked the voltage coming out of the orange wire  (o)  get a reading of 21 volts from the tstat to the actual valve the voltage is 21 volts causing the valve to rapidly click but there not enough volts to keep it engaged. does anyone know have a fix for this also all other wires have 24 volts IE: red and yellow. is there a fix for this.

[Houptee]

Not sure what is causing this I never heard of this before.

Hopefully the Nest tech reps on here will respond with some info.

I think the base contains transistors and makes the connections R to O but not totally sure how the internals are designed. I saw some posts on here where the customer was sent a new base.

Wish I could help more.

[Markjosephp]

Hi folks,

I'm chiming in to ensure everything was covered here.

I appreciate all the steps you've both taken, and we'd be happy to take a look at this. Could you please fill out this form with the needed information? A member of our support team will be in touch over email to help.

I appreciate your help here, @Houptee.

Regards,

Mark

[Markjosephp]

Hi there,

@macair42, thanks for completing the form; we have received it. Soon, a member of our upper team will contact you via email. Also, please continue the conversation there for more information.

@hitecmal, I'm checking back in — how's it going? Have you managed to fill out the form as well?

Regards,

Mark

[Jenelyn_O]

Hello there,

Chiming in — were you able to fill out the form? Please let us know so we can move forward. 

I appreciate your help, @Houptee and Mark. 

Best,

Jenelyn

[Jenelyn_O]

Hi folks,

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 need assistance or want to discuss topics, feel free to start a new thread.

Thanks,

Jenelyn

[macair42]

I have replied twice to your posts the first of which had a completed form you requested containing details of the problem my customer is having with her Nest thermostat.  The only thing I receive from you is an email stating you are waiting for me to respond to your emails.  Google (and Nest) is about to lose a supportive contractor and customer because of lack of a helpful response to a serious technical support issue.

Joe McIntosh

McIntosh Heating & Air

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[Markjosephp]

Hello Joe,

I'm sorry for the delay. I followed up with the upper team for the next step. Please check your inbox, spam, or junk folder for the updates, and we'll leave this thread open until you get assistance.

Regards,

Mark

[Markjosephp]

Hello Joe,

I'm sorry if it took a while. I see that our upper team sent you an email. You should have received it by now, and you can continue the conversation from there, as this thread will be closed in 24 hours.

Best regards,
Mark