Heating 3rd

[Zboww]

Thermostat (35rd Gen Learning) 

In heating mode the outside condensers do not come on for either unit.  The air conditioning mode works good, but the heat mode the outside condensers do not come on.  This is a heat pump, there are no O/B wires used. Using wiring Y1,G, RH, C, W1.....  

As mention all works good in air conditioning mode, first time trying in heating mode..... if I jump the RH, W1 wires  manually, heating works fine, but when using thermostat not working

[CoolingWizard]

@Zboww, if you indeed have a heat pump and do not have a gas furnace, in order to cause a heat pump to change modes from heating to cooling or cooling to heating you must change the reversing valve on the outdoor unit. The control wire for the outside heat pump reversing valve is typically the O or a B wire. If you get a moment, please upload a picture of your old thermostat and all the wires attached to it so we can verify for you. Another thing you can do is get me the model number of the outdoor unit and I can check my manuals to verify that it’s a heat pump for you  

AC Cooling Wizard 

[Zboww]

Yes, thank you. This is an entirely new hvac system environment.  Goodman air handler and condenser.  

Condenser model is GSZC703610AB and the Air handler model is GSZC703610AB.  I have units for the 1st & 2nd floor, both 3rd Gen Google Nest providing the same results....  The Air handler is giving the correct codes for heating HP HT A10, except the condenser never comes on.   Thank you AC Cooling Wizard

[CoolingWizard]

@Zboww , you provided the same model number for both the condenser and the air handler. A goodman GSCZ series is a Heat pump outdoor unit. 

AC Cooling Wizard

[Zboww]

Okay, model for Air Handler  AMVT42Cp1400AA, 1st floor air handler 2nd floor air handler same, ends in BA. 

[CoolingWizard]

@Zboww , 

You have properly matched indoor air handler. The air handler should be connected to the outdoor unit using only 2 wires attached to the outdoor heat pump. 

For this to work correctly, your Nest thermostat should not be configured as a heat pump. There is no O wire needed.  See the attached screenshot of the installation manual. 

 For this highly advanced system configure you Nest Thermostat as a Air Conditioner with Electric Heat with Forced Air delivery. 

Your Nest Wires should be:

Air Handler to  Nest

R to Rc

Y to Y1

W to W1

G to G

C to C 

When the air handler sees the call for Heat, it will signal the outdoor unit to switch to heat mode and turn on. 

AC Cooling Wizard

[Zboww]

Yes, this is the diagram have been using, the condenser does come on in air conditioning mode, not heat mode. The higher level manufacture support, said I should place in gas mode, force air, rather than electric mode.  

Only difference I had from your recommendations, was using the RH for power, not the RC.  Other than that option moved wires on T-stat to the RC now for power.   Do the RC a & RH make a difference, both are for power on the T-stat.   I just saw your email, it's about 80 degrees here, would test the heating mode further.

Also, how does the emergency heat mode work with this T-stat, I have installed a 10kw kit, but unsure how will function with the Nest T-stat.  

Thank you

[CoolingWizard]

@Zboww , 

if you have a heat strip in there, and do you want to connect it to your emergency heat control on the thermostat you would attach that to the programmable * terminal. 

Do you feel comfortable opening up your air handler ?