Trying to understand what system I have and what means what

[Dcisfun5]

Hi. I have a climatemaster water sourced heat pump. I live in a condo and the old thermostat is about 2003 (not digital). I am trying to understand the wiring setup because it does not appear to follow standard wire colors. We have only 4 wires.

1. We have a Black wire that connects to O on both the heatpump and thermostat.

2. We have a White wire that connects to Y on the heat pump and P on the thermostat (this is the odd one since I cannot figure out what the purpose of P is?).

3. Green wire to G on both heat pump and thermostat.

4. Red wire to R on both heat pump and thermostat.

There does not appear to be emergency heat. The thermostat does not have a selection for this. 

I requested help from the compatability helper but it did not know what P was either. Since the White wire connects to Y on the heat pump would I just connect it to Y on a thermostat? Or would the Nest need to have a P also? I have not purchased a Nest yet as I am still trying to determine if it will work for my system.

Any insight is appreciated. Thanks!

[Markjosephp]

Hello Dcisfun5,

Thanks for reaching out to the Google Nest Community Forum. I'd be happy to take a look at this for you.

The P terminal is usually for the sensor. Your thermostat likely doesn't have one built-in. To be sure, could you please share with me a photo of your thermostat's wiring and your HVAC system's make and model? This would help me identify its compatibility.

I'll look forward to your response.

Regards,
Mark

[Jenelyn_O]

Hi there,

Chiming in — I just want to check if you managed to see the response above. Please share with us the needed information, as it will help us to move forward.

I appreciate your input, Mark.

Best,

Jenelyn

[Jenelyn_O]

Hi Dcisfun5,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns, as I'll be locking this thread in 24 hours.

Thanks,

Jenelyn

[Dcisfun5]

Hi, thank you for reaching out. 

The model of the hvac is a water sourced heat pump Climatemaster.

Attached are pictures of the thermostat wiring ATM 11H02 and the hvac model GRV030BGC40TLTS. Both are climatemaster.

Let me know if you need more info/pictures.

I tried to attach the photos but I am unsure how. Please let me know

Thank you!
Crystal

[Dcisfun5]

 

[zoeuvre]

Hi folks, 

Thanks for stopping by, Mark and Jenelyn. 

@Dcisfun5, thanks for posting here in the Community forum, and I'm sorry for the delayed response. I want to check if you are still in need of any help. If so, your system is identified as a heat pump system based on the thermostat wires you have. Therefore, your thermostat wires are compatible with any of our Nest Thermostats and should be wired to the Nest Thermostat base as follows: 

• White wire to W or W1
• Green wire to G 
• Black wire to *OB or OB
• Red wire to R or RH
   

Also, here’s a guide for the installation and set up of a Nest Thermostat. 

Let us know if you have any other questions. We’re happy to help. 
 

Best regards,

Zoe