No Cooling and E105 Error

[rashafaa]

Hey all, 

I have installed the following configuration. I get a combination of heat when it should be cooling and an E105 error. I'm confident it's a simple fix in moving a wire, but am wondering if my setup may not be compatible. Any help is much appreciated!

[Lance_L]

Hello rashafaa,

Thanks for reaching out to the Google Nest Community.

I’m sorry to hear that you’re having issues setting up your Nest thermostat. I’d like to dig deeper into this. Let’s check it out.

A few questions: what country are you located in? What model of Nest thermostat do you have? Is this a new installation? What kind of HVAC system do you have? Also, are there any recent power outages or electrical work done in the house?

If you have a conventional system, here’s a handy guide to help you troubleshoot strange heating or cooling behavior.

For heat pumps, here’s how to troubleshoot heat pump issues.

Let me know if you have any questions.

Best,

Lance

[rashafaa]

What country are you located in? United States, Florida Panhandle

What model of Nest thermostat do you have? Brand new learning thermostat, newest model.

Is this a new installation? Yes

What kind of HVAC system do you have? It's electric and otherwise appears to be a standard central air system. Heated/Cooled.

Also, are there any recent power outages or electrical work done in the house? No

[Lance_L]

Hi rashafaa,

Thanks for the responses. The E105 message indicates the Nest thermostat has an overcurrent error. Can you post a photo on how the wires are connected to the base of the Nest Learning Thermostat? Also, may I know what is the make and model of your HVAC system?

Regards,

Lance

[rashafaa]

It is a few-year-old Lennox. I'm no longer at the property, so I can't take a photo. 

I tried multiple wiring configurations after reading posts on here. 

Red - RC

Yellow - Y

Blue - C

Orange - Originally to W1, then moved to O/B

Green - G

White - Originally to W2, then moved to the Asterisk

[Lance_L]

Hey rashafaa,

I gotcha. Once you’re back at the location, I’d suggest double-checking the make and model of your HVAC system.

You may have a heat pump, in which case connect the wires as follows:

• Yellow: Y1
• Green: G
• Orange: O/B
• Red: RC
• White: W2
• Blue: C

Call for cooling. If the system blows warm air in cool mode, change the settings for the orientation of the heat pump.

1. On your thermostat, go to Settings.
2. Select Equipment.
3. Select Continue > Continue.
4. Select Heat pump.
5. The Nest thermostat defaults to an O setting for heat pumps.
6. If the O option is highlighted, select B. If the B option is highlighted, select O.
7. To make sure that the issue is resolved, test your heating and cooling again.

Keep me posted.

Best,

Lance