R and C wiring for Air Handler and Zone Panel

Question

First time posting a question! But have been reading the questions/answers here for a while now.

Ok- so I have a brand new Goodman Heat Pump system (GSZC + AVPTC air handler) I’ve installed in my house. My duct layout is broken out into 3 zones. I have 3 Nest thermostats, one for each zone. Zoning is controlled by ZoneFirst H32P panel. The zone control panel has a dedicated 24V transformer that provides power to the dampers and will also power the thermostats (from Rc to C terminals on both Nest and zone panel).

My air handling unit (Goodman AVPTC) has its own 24V transformer which powers the control board in the air cabinet, and if wired appropriately can power the thermostats (I’ve tested this by bypassing the zone control panel and wired one thermostat directly to air handler).

My question is what is the right way to have the R and C wires set up for this application where there is a dedicated transformer for each piece of equipment? Should I not have an R wire going from zone panel (top right in picture) to air handler board? My thinking is it’s not necessary to have an R connection between zone board and air handler they’re getting their own 24v supply?

Below is image of the zone control panel:

And here’s a picture of the terminal block in the air handler (pay no attention to wires connected at the moment):

Answer 1

You should wire this controller according to its documentation. It's pretty clear. Each thermostat needs R, C, and the other control wires connected to the appropriate zone terminals. Each heat/cool/fan device needs its own R, and all the rest of its own signal wires except C to be connected to the appropriate terminals. Exactly per the documentation.

It seems that the only actual question you have is whether you can skip the R wires from the pump and blower to the controller. You cannot. Yes, they have their own power supplies, and it is via the R wires and the controller that those power supplies function. The controller looks like a thermostat to each of the pump and blower, and needs the R wire just as if it was a thermostat. The controller doesn't need (and has nowhere to connect) C wires from those devices because it doesn't need their power for itself.

It might help you to imagine the controller, simplified, as nothing more than a light switch, on/off, that controls the pump and fan. In the case of the fan the "light switch" just connects the R to the G wire. It can't do that if it doesn't have the R wire! Unlike the thermostats, it doesn't need that R (and C) wire to power itself, but it still needs it to do it's main task ... turn on the fan.