zone system with 2 nest Thermostat E

[RandS1]

I have a zone system, heat pump, 2 nest Thermostat E controllers.  Zone 1 is configured with all wire as marked by color and I have confirmed that the white wire is connected to the O/B terminal on the controller and the *O/B terminal on the Nest terminal.  This is for zone 1 and it works a advertised, heat comes on, cold comes on, pump switches, etc.  

When I hook up zone 2, a conventional thermostat works with basic connections but when I try to switch it out for a Nest thermostat E, it does not work correctly.  first tried to hook up exactly as zone 1, all wires in the same place at controller and thermostat.  When white wire is attached to *O/B on Nest, Nest does not show option for heat, only cool, eco and off.  When I move the white wire to the W terminal on Nest, to mimic the conventional thermostat, heat show up but the controller does not turn on the heat pump.  I need to use the zone 1 controller to turn on the heat.

Both zones on the controller board are set up the same, and the conventional thermostat works with wires placed in the standard R, Y, G, C, and W locations.  As I write this, this sounds like a controller board issue but I do not understand how the controller board knows that I am using a Nest controller vs a conventional controller.  

Why does the Nest not function like the conventional controller.?

[CoolingWizard]

@RandS1 ,

With zone systems the zone controller board is shall we say, “in charge.”

On 99% of all zone controllers the thermostat connected to Zone 1 is the primary controlling thermostat. It is the zone 1 that sets system mode to either Heat or Cool. Your Zone 2 thermostat can only open the zone damper, and if the feature is available, start the system when Zone 1 thermostat is not active.  Typically however, Zone 1 must be calling for heat or calling cooling before Zone 2, 3, 4 can be serviced

Zone-2, 3, and 4 should be wired as R, Y, G, W and if available C. 

AC Cooling Wizard

[RandS1]

Thank you for the information.   Reminder that I have a heat pump system.  Zone 1 Nest is wired R, Y, G, C, O/B and controls everything fine.

I was able to get hold of Honeywell and they said that the 2 zones are completely independent from each other.

I guess I can live with zone 1 deciding if I am in heat or cool but I don’t want have to turn on heat in zone 1 in order to turn on heat in zone 2.

My question is, a conventional thermostat wired up as R, Y, G, C, W (where W goes to O/B on controller board) works without zone 1 being on, and turns on the compressor and fan.  When I hook

up the Nest to the same wires, it says it is in heat mode but it does not turn on the compressor and fan stays on low speed.  I am now guessing this is because the Nest is set for Electric (not gas) so it is sending control through the O/B connection.  If I move the W wire to O/B on the Nest, it does not even give an option for heat, only cold and fan.  If I turn on cold, it turns on the heat at the controller.  This is probably because zone 1 is set to heat, which like you said is the primary controller for setting heat or cold.

How does the controller board know what type of thermostat it is?  The Nest zone 2 is currently set to equipment type Electric.  Maybe if I program the zone 2 Nest for gas, Then it will mimic the  conventional controller and send signal to W instead of O/B.  W is connected to O/B at the controller board so heat pump functions should work as expected.

Will keep you posted.

[RandS1 · Accepted solution]

Update.  I was able to get it working.  hooking up R, Y, G, C, W to corresponding pins on Nest and programming it to think it was a gas furnace did not work. 

Moved W from W slot to O/B slot on nest.  In this setup, Nest would not give the option for Heat, only Cool, and when it did to go Cool, it turned on the heat.  Went back into nest programming and switched the individual O setting.   It then allowed heat option and switched on the compressor in heat mode.  Went back and verified that cool still worked.

Both controllers are working fine now, just have to put everything back together.

Thanks for the information.