heat comes on instead of cold on new install

[imj]

Hello,

After what I thought was going to be a simple wiring job on a new basic nest, I was surprised to see the heat come on when calling for cold.

This is a conventional ac/heating platform, no heat pumps involved.

This is the wire mapping from the original Honeywell thermostat:

W2 white
G  green
W  orange
C  blue
Y  yellow
R  red

The only thing different on the nest mapping is that the white wire went to the OB connector since the nest doesn't have a dedicated W2 connector.

Thanks in advance for any help that anyone can offer!

[CoolingWizard]

When you follow the instructions for installing your nest thermostat, you were instructed to take a picture of your old thermostat in the wires that are connected to it. Can you do me a favor and post that picture so I can see the old thermostat and see the wiring on it so I can help you best .

AC Cooling Wizard

[imj]

Certainly, here's the original wiring followed by the nest version I tried:

 

 

[CoolingWizard]

@imj , You need to reverse the White wire and the Orange wire.  The White wire goes to Nest W and is Auxiliary Heat. The Orange wire goes to OB and is the heat pump reversing valve.  Set you system configuration as a Heat Pump, Forced Air, and set the W as Auxiliary Heating. 

AC Cooling Wizard

[imj]

Hi Wizard,

Can you tell me in what menu those options (Auxiliary Heat, etc) come up, because I didn't see anything other than basic questions like what kind of heat source and fuel are used. I thought it might be under Settings/Equipment but I don't see anything relevant in their either.

I did try just reversing those two wires but on it's own, that still caused the heat to come on.

I even tried selecting the "Pro Install" option to see if I get different options, but that one skips the wifi setup and exits setup without having created a new device.

A few pics to illustrate...

 

 

 

[CoolingWizard]

@imj , since you have a heat pump, you have to understand that more than one type exist out there. We know them as type O or type B. The default is type O and you must have a type B so we have to go into the equipment settings, heat, and then you’re gonna see an option for the heat pump and it’s gonna have a checkmark by oh you need to move the checkmark to B and that will solve your problem. 

AC Cooling Wizard

[imj]

So I understand that, but what I can't figure out why my Settings/Equipment menu only has 4 options in it, none of which let me make the change you tell me I need. My only options are:

Wiring Info

Power Info

Power Connector

Back

[CoolingWizard]

@imj , if you go into the pro set up screen, you’ll see the wire set up and then you go to the next screen and then you can tap the OB wire and change its function. You can change it from a O model to a B model and this should solve your problem.

AC Cooling Wizard 

[imj]

Thank you, that makes sense and I'll give it a try.

I had tried the pro set up earlier (skipping over the page where it asks you about your pro number), but I vaguely remember it asking me the same questions as the non-pro version. The only difference I remember was that the setup exited without having tried the wifi setup and in the end, the device didn't even get added to the Google Home device list.

[CoolingWizard]

@imj , I have to admit that I don’t have much experience working with the original basic nest thermostat I always use nest learning thermostats for my customers. The only thing I can do is guess that if you go into wiring info, do you see a picture of the back plate and what wires are currently recognizes plugged in or do you just see a list of wires? There has to be a way to see the Heat Pump wire, and change it from O to B.  

AC Cooling Wizard 

[imj]

If you scroll up a bit, I posted a pic of what it shows you for wiring info. It seems to find the right ones.

But yes, I can't believe there isn't a way to do the O/B switch. All the you-tube examples show the learning thermostats, not the old dumb one that I'm working with here.

[CoolingWizard]

@imj , lets try this. With orange wire in OB and the white wire in W, perform a reset to factory. This time when it you go into Pro Setup, enter the code 5C8D3E and then set OB to type B and W to Auxiliary Heat. 

AC Cooling Wizard

[imj]

Hi @CoolingWizard  and @catheryn ,

Sorry for not replying; he passing hurricane sort of pushed this out on the backburner for a while.

Anyway, I did get it working by telling the app that I had an O/B wire despite the fact that it was connected to W2 on the Honeywell. I think that was the trick.

BTW, I did try the pro number, but the app would repeatedly quit without adding the device to the Home panel, leaving no way to configure the Wi-Fi.

So it's working, but I never was able to get to a screen where it would let me change the sense of the O/B wire if I had needed to.

Thank you!

[catheryn]

Hi @imj,

Thanks for posting in the community. I apologize for the inconvenience caused by your Nest Thermostat.

Please let me know if you still require assistance with your device. I'm here to help you troubleshoot any issues you may be experiencing.

Best regards, 

Catheryn.