Nest 3rd Gen Thermostat, heats when in cool

[Bbradleybales]

I installed a new nest 3rd gen learning thermostat.  Wiring was all done correctly.  However, when set in cool it heats.  I confirmed the wiring configure for old Honeywell thermostat and the cooling wires for it were connected to cooling for nest.  I uninstalled the nest and put back the Honeywell.  It is cooling.  Same cooling wires that were going to Y1, Y2, and G on nest.  I don’t know why the nest was running heat??

[Patrick_Caezza]

Post a picture of the original thermostats wiring here.

Try this if you have a 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. 
   • If the O option is highlighted, select B.
   • If the B option is highlighted, select O.
6. Test your heating and cooling again to make sure the issue is resolved.

[Bbradleybales]

On the new Nest thermostat I had Y1 yellow, Y2 black, G green, Rc red, W1 orange, W2 white, and C blue.

I am attempting to attach a photo of old wiring from my phone, but not getting it to work.

[Bbradleybales]

 

[Patrick_Caezza · Accepted solution]

Give this wiring a try

Black - E to * (set as emergency heat)

White - W2 to W2 (set as AUX heat)

Green - G to G

Orange - O/B to OB

Blue - C to C

Yellow - Y to Y1

Red - Rc to Rc (jumper to R not needed))

[stevenwhite8484]

if you have a heat pump the orange needs to land on the O/B if its still heating when in cool then the thermostat isnt communicating with the orange wire telling the reversing valve in the heat pump to switch to cooling mode. You can bypass this however and manually make the unit switch but you would have to be a little handy to do this. unfortunately a new thermostat might be required to permanantly fix the issue

[Bbradleybales]

Got it.  So, it does turn out that the unit is a heat pump.  When looking at the wiring in the old thermostat, even though the wires come in from the top should I be reading them as the bottom labels?  Red as Rc, Yellow as Y, Blue as C, Orange as O/B, Green as G, White as Aux, and Black as E?

[stevenwhite8484]

correct ive replaced a few of those thermostats for the reason you are claiming actually in my own home haha i had to jump the reversing valve until i got a new one.

[Bbradleybales]

Thank you for all of your help.  I have installed both Google Nest thermostats and they are both working perfectly.

Couldn't have done it without your help.  Thank you again!

[MelbaDT]

Hey folks, 

Thanks for answering, Patrick_Caezza. 

Bbradleybales, glad to hear that you've managed to sort it out with the help of Patrick's suggestion above ― hat's off to both of you!

Feel free to let us know if you still have some questions in mind. 

Best, 

Melba

[MelbaDT]

Hi, 

I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.
 

Best, 

Melba