Aprilaire thermostat 8363 to be replaced by learning nest thermostat

[Alkeshc]

 

I have 2 Aprilaire thermostats which control my heat pump air con on 2 levels/floors in my home. I want to replace them with nest learning thermostat. I have wires connected to RC RH G Y W terminals on both the thermostats. Will I need a C connector ? Or I just need to replace the Aprilaire with Nest ?

[CoolingWizard]

@Alkeshc , it looks like there is one more unused conductor tucked on the wall. This unused wire appears to have black insulation color.  This wire can be connected to Common at both ends.  I always recommend using a C wire.  

AC Cooling Wizard

[Alkeshc]

Thanks for the revert @CoolingWizard . If I don’t connect the black wire at both the ends and don’t use a C wire, will the nest still work ?

[CoolingWizard]

@Alkeshc , that depends on your furnace/air handler control board.  The Nest Learning thermostat, in many cases, can reach the power common by using the W or Y wire.  In the best practices, a wire connected to C and both ends is best 

AC Cooling Wizard

[Alkeshc]

Hi @CoolingWizard , thanks for all your help and giving me the courage(lol) to DIY. I just connected the 4 wires (no C wire) and for the moment nest is not showing low battery. If there is any change then I will post here again.

Thanks again for replying to my post.

[Jenelyn_O]

Hi there,

Thanks for reaching out. I'm glad to hear that your Nest Thermostat is no longer encountering power issues. Please feel free to create a new thread if you have any questions or concerns, as we'll be willing to assist you from there. Otherwise, I'll be locking this thread after 24 hours.

I appreciate your help, @CoolingWizard.

Best,

Jenelyn