have 2 thermostats want to operate from 1 Nest 3rd gen

[salx777x]

I have 1 thermostat with a White wire and Red wire, this controls my Gas Furnace Baseboard heating. 

I have a 2nd thermostat with a A/C with heat pump (Yhe42b23s) model

I need help installing the wires in the right place in order to use the AC heat pump when the temp. is not as low and utilize the furnace once the temp. goes below 40 degrees. (if anyone has better recommendations on what is the best set up for this set up please let me know). 

Thank you and look forward to any help that can be provided. 

[CoolingWizard]

Salx777x,

What you are asking to do would not be easy to do.  First of all you would have to have a thermostat which would have specific software designed to support a duel heating system such as heat pump and gas furnace. There are not enough residential needs of these unique situations to warrant such a thermostat to be designed. There are commercial/industrial systems that can do this.   However this are very expensive control systems. 

At best in a residential environment,  you can try to set the gas boiler/baseboard heat to be the Auxiliary heat.  If you are using the heat pump and it goes into defrost mode, the thermostat will turn on the auxiliary heat. What cannot be done is to set/program any residential thermostat  so that when auxiliary Heat is to turn on when the temperature falls below 40° ambient outdoors, to turn off the heat pump at the same time.

most residential thermostats that are designed to work with heat pumps, will automatically initiate auxiliary heat, sometimes called emergency heat, when the heat pump either is in defrost mode or the temperature split between set temperature and return air temperature are so far apart that auxiliary heat is needed to boost the heat pump. However this  typically does not occur until the ambient outdoor temperature falls below 0°  Fahrenheit.   

Ken

[salx777x]

would you suggest I use 2 nest devices, 1 for the A/C with heat pump and a separate one for the furnace baseboard heater, connect them on my nest account as separate zones or something like that? 

Thank you for taking the time to replying to my message. 

[CoolingWizard]

I assume at this time you have two separate thermostats; one for the heat pump, and a second for the baseboard heating system. Using a second Nest Learning Thermostat for the baseboard heating system would allow you to program the baseboard heat to be activated given a given set temperature.  Or, using human interaction, use your Goggle Home App or the Nest app, to turn on the baseboard heating system and turn off the heat pump.  

You can go so far as to have the Nest controlling the baseboard heating system come on at a set temperature a degree or two below the set temperature of the heat pump Nest. Thermostat. This would make the baseboard heating system a booster heating system for those really cold nights.  

Ken

[Jake]

Hey there,

I wanted to check in with you, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake

[Jeran]

Hey there salx777x,

I'm just checking up on this thread, did you have any more questions or need any additional help? 

Thank you for helping out on this thread, CoolingWizard!

Best regards,
Jeran
 

[Jeran]

Hey there salx777x,

Did you have any more questions or need any additional help? 

Thank you,
Jeran