Nest Thermostat Gen4 starts then fan runs only

[Mark-ABQ]

Tried installing Nest gen 4 thermostat yesterday….   System seemed to start okay but after running for a few minutes heat pump stops and only fan blowing cold air.  

When checking the different settings the status shows good input power is 7.145V.

Wiring Info shows: connected to Y1-OB-G-Rh

N405: No power to W2/AUX wire detected

Help…...

(can’t figure out how to post pic of old wire configuration except to say 5 wires from unit R-Y-G-B-W there was a jumper in R/RC and Aux/E)

[Harleyeg05]

I'm experiencing the same thing. 

But with me I'm dealing with the WHITE wire in the O/B.

I'm going to try and place it on the W location based on a web page troubleshoot idea

[Michal_007]

I'm experiencing the same issue with my setup. I'm dealing with the WHITE wire in the O/B terminal, and I will try moving it to the W location based on a troubleshooting tip I found online.

[catheryn]

Hi there! 

Thanks for bringing your concern to our attention and posting it in the community. I’m really sorry to hear about this experience with your Nest Thermostat 4th gen just blowing cold air and showing the N405 error message.

I understand that you’ve already checked the input power and everything seems to be in order. But no worries, let me help you with that.

Before we troubleshoot, can you share a clear picture of the wiring? Also, please reply with the following information:

• Did it work before? When did the issue start?
• Was the HVAC system working properly with the old thermostat?
• When was the last HVAC maintenance?

In the meantime, you can check this article: Troubleshoot Nest Thermostat help codes for additional support.

Let me know how this goes, and we’ll find a resolution together.

Thanks, 

Catheryn