New Nest 4 thermostat no heat and no cooling on heat-pump system

[Rappyripper]

Hello everyone,

I removed my old thermostat (Tecson) for my heat-pump system and I have no cooling and no heat.

Tecson Thermostat wiring:

G - Brown

C  - Blue

R  - Red

W1    

Y  -  Yellow and jumpered to W1

O - Black

On my new Nest:

Y1  - Yellow

G  - Brown

OB  - Black

Rc  - Red

C - Blue

I followed the instructions and it passed the wiring check but it does not kick in, no fan, no compressor no nothing.

No error messages anywhere. 

Does anybody know how to make this work please? 

Thanks in advance and best regards,

JB

[GabrielaG]

Hi @Rappyripper,

Thanks for reaching out to the Google Nest Community. I understand that you need assistance with the wiring on your Nest Learning Thermostat 4th gen because your heat pump system is not cooling or heating. I appreciate the information you provided about your wiring. I'm glad to help you.

To provide you with accurate troubleshooting steps, please help me out by answering the following questions:

• When did you install the Nest Thermostat?
• Did you also try swapping Y1 and W1, then calling for heating?
• Have you checked the O/B wire configuration and tried changing the O-wire to the B-wire configuration or vice versa? 

Any additional details you can provide will be helpful.

Regards,

Gabriela