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Nest 4 Providing Heat Only, No Cool Air

kylebaughman
Community Member

After the compatibility check we purchased the Nest 4 for our home.  Installation was easy enough and we followed the instructions to install.  The display did not indicate any issues or error codes, but the Cool setting will only provide hot air.  We tried looking through message boards and did not find an adequate answer for this issue.  

 

Our available wires were: R, Y, W1, G, W2 and had a wire connecting the Y2 and W2 that was not connected to the wall, presumably for the dual system(?).  When installing we connected the R, Y, W1, G and W2 but did not include the wire connecting the Y2 and W2 ports.  The heating/cooling system is electric and includes a heat pump.  Where did we go wrong?

1 Recommended Answer

CoolingWizard
Platinum Product Expert
Platinum Product Expert

@kylebaughman ,

your old thermostat was wired as a heat pump. The white wire is going to the auxiliary heat with a jumper from there over to emergency heat.

The blue wire is wired to the reversing valve O/B. ( to Nest OB)
The yellow wire is wired to Y. (To Nest Y1)
The red wire is wired to R. (To Nest RC)
The green wire is wired to G (to Nest G)
The white wire is wired to Aux with a jumper wire to E. (To Nest W2/Aux)

 

AC Cooling Wizard

NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.

View Recommended Answer in original post

3 REPLIES 3

CoolingWizard
Platinum Product Expert
Platinum Product Expert

@kylebaughman ,

can you do us a favor and post the picture you took of your old thermostat wiring base so we can see what wires were attached to what standard HVAC terminals?

AC Cooling Wizard 

NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.

Screenshot 2024-10-31 at 10.51.49 AM.png

CoolingWizard
Platinum Product Expert
Platinum Product Expert

@kylebaughman ,

your old thermostat was wired as a heat pump. The white wire is going to the auxiliary heat with a jumper from there over to emergency heat.

The blue wire is wired to the reversing valve O/B. ( to Nest OB)
The yellow wire is wired to Y. (To Nest Y1)
The red wire is wired to R. (To Nest RC)
The green wire is wired to G (to Nest G)
The white wire is wired to Aux with a jumper wire to E. (To Nest W2/Aux)

 

AC Cooling Wizard

NestPro, Google Pro, Mechanical Engineer and HVAC service company owner.