Dual zone dual fuel

[DIYg]

Hi! Of course the compatibility program says we need to ask a Pro. Sigh. Maybe someone here can help please? @CoolingWizard you appear knowledgeable: maybe you have some insight to share too?

we have 2 American Standard ACONT803 thermostats, 1 gas heater, 1 heat pump/ac, and zone heating. I don’t care for the heat pump but it’s a nice backup should we ever run in to issues: if we have to lose it for heating that’s fine. 

wires y - g - b - r - o - y2 - x2 - w1 - s1 - s2

lose the S sensor? That’s fine since Nest uses WiFi. What else would we lose — or could we even use this thermostat?

[CoolingWizard · Accepted solution]

@DIYg , you must have a zone controller attached to your indoor air handler. Your thermostats are in all likelihood attached to say something like an HZ322 zone controller.  If not, then you would have two separate outdoor and indoor units.  

AC Cooling Wizard

[CoolingWizard]

@DIYg , You are correct that you do not need the two temperature sensor wires S1 and S2. You appear to have a 2-stage heat pump with auxiliary heat.  Your system would be considered “duel fuel” if the furnace and indoor coil air connected. That is to say that the indoor coil is either below the furnace or on top of the furnace and the airflow flows through the furnace and through the indoor coil. 
The X2 wire is generally stage 2 heating with furnace. With a Heat Pump, the X2 is used as auxiliary heat control from the heat pump outdoor unit. Once again though, of you have Duel Fuel system, the X2 could be being used as stage-2 has heat. 
In order to figure this out better, I need the model number of your indoor furnace. Of possible take a picture of the unit so I can see the arrangement indoor coil and the furnace cabinet. 

AC Cooling Wizard 

[DIYg]

Thank you @CoolingWizard ! So I guess not dual fuel? I thought maybe heat pump and heater would be that way, but there’s not another coil. I’ll take a look when I get home but I know American Standard Heritage 13 is the outside unit. 

So based on your response — assuming the heater is in line with that you are thinking it is — the Nest Learning would work?

[CoolingWizard]

@DIYg , how many thermostats does your home currently have? With your Heat Pump you have have an indoor coil. On AC cooling mode the refrigerant is compressed outdoors and sent to the indoor coil on a 3/8” cooper pipe.  In the indoor coil the refrigerant gas is metered into the indoor coil where it gathers the heat that boils the refrigerant and leaves cold air behind. The refrigerant carries this super heated gas goes back outside on the larger, insulated pipe, and outside the heat is rejected into the air.  

In heating mode the reversing valve changes the flow of refrigerant and brings heated refrigerant to the indoor coil where the heat is rejected into the air stream. Inside the indoor coil the refrigerant gathers the cool air leaving warm air indoors.  

Just look for the cabinet that has the two copper pipes entering it remembering that the bigger one will be inside closed cell rubber insulation.  

With a heat pump, you will need a Nest Learning Thermostat.  

AC Cooling Wizard

[DIYg]

@CoolingWizard American standard freedom 80 2-stage acculink. Ultrazone dampers. And 2 thermostats. I’m only thinking of replacing one to start and try it out. 

[CoolingWizard]

@DIYg , if you have two separate thermostats , can you take a picture of each one showing the wires attached to each one? If your system is using AccuLink, you might have a compatibility problem. 

AC Cooling Wizard

[DIYg]

@CoolingWizard wish I could attach but from the phone and tablet I don’t get the option. Maybe the computer but let’s see if this works for you:

R

O

Y

G

B

X2

W2

S1

S2

Y2

[CoolingWizard]

@DIYg , make sure that you have verified your email address,. When you first set up an account here, you get an email from Google asking you to verify your email address. If you don’t verify your address you cannot upload pictures. Look for an email that’s asking you to verify your address from Google communities

AC Cooling  Wizard

[DIYg]

@CoolingWizard  both are the same

 

 

[CoolingWizard · Accepted solution]

@DIYg , you must have a zone controller attached to your indoor air handler. Your thermostats are in all likelihood attached to say something like an HZ322 zone controller.  If not, then you would have two separate outdoor and indoor units.  

AC Cooling Wizard

[DIYg]

@CoolingWizard yes Ultrazone 

 

 

[CoolingWizard · Accepted solution]

@DIYg , each thermostat is connected to the EWC zone controller.  The Zone Controller is what connects to the HVAC equipment.  You will need a Nest Learning Thermostat for each location. 

AC Cooling Wizard 

[DIYg]

@CoolingWizard so the learning thermostats WILL work? And can I start with one or will we need to do both at the same time?

[CoolingWizard]

@DIYg , Yes they will work well.

AC Cooling Wizard