Wiring photo to check compatibility

[ISG]

Posting photo to check compatibility 

 

[Homeowner333]

 

[Homeowner333]

I see at least one more wire not attached to anything.  Only the 3 wires on the right seem to be connected.  

[CoolingWizard]

@Homeowner333 , your thermostat is a digital communicating thermostat using a proprietary communications system.  The D is the Data +, the C/B Is data ground.  This system is not compatible with the Nest Thermostat or any other conventional thermostat.  

AC Cooling Wizard

[CoolingWizard]

If your current thermostat does not have any wire attached to the R terminal, your thermostat cannot control or operate your furnace. 

AC Cooling Wizard

[slava1]

 Red wire is not connected. Is it compatible?

[alexr]

From what I can tell, there is only an R, B, and W wire.  This is for a fujitsu mini split.  Am I stuck doing something like this https://www.googlenestcommunity.com/t5/Nest-Thermostats/Fujitsu-UTY-TTRX-Nest-step-by-step/m-p/27918 or will a standard nest thermostat work?

[CoolingWizard]

@alexr ,

Mini-splits, sometimes called ductless, use a digital property communication that a conventional thermostat like the Nest Thermostat are not compatible with. 

AC Cooling Wizard

[Mashaan]

I have siemens thermostat I just wanna check if my wires are compatible with google nest thermostat before buying it because it seems that I have a lot of wires here !

[CoolingWizard]

@Mashaan ,

I do not recognize your thermostat. Can you provide me the  model number of your thermostat please.

AC Cooling Wizard

[Dwight3152]

Would the nest learning thermostat work with my wiring setup?

[CoolingWizard]

@Dwight3152 ,

your thermostat is controlling a heat pump with auxiliary and emergency heat. You will need a Nest Learning Thermostat 3rd generation to support your system. 

AC Cooling Wizard

[jdeangelis005]

I have a photo but no permission to add it.

[jdeangelis005]

Trane thermostat

[CoolingWizard]

@jdeangelis005 ,

Do know if you have a heat pump system or do you have an Air Conditioner and a Gas Furnace?

AC Cooling Wizard

[jdeangelis005]

Forced air gas furnace with central air.

[jdeangelis005]

Just a gas forced air furnace & central air

[jdeangelis005]

No Heat pump, 

Forced air gas furnace with central air.

[CoolingWizard]

Can one of your administrators please LOCK this thread.  thank you. 

[Justin_Dell]

 

 I am not sure if this would be compatible. It doesn’t have a posted voltage, just states high voltage.

 Any help?

[CoolingWizard]

@Justin_Dell ,

That thermostat uses standard line voltage of 120VAC to control a heating system.  It is not compatible with a conventional type thermostat such as the Nest Thermostat.

AC Cooling Wizard

[Jabirp]

This is my existing thermostat with three wire. this is communication type thermostat for our trane Package AC. Is it possible to connect Nest thermostat instead of the old one? 

[CoolingWizard]

@Jabirp ,

this all depends on your thermostat cable and the indoor and outdoor units control board.  You need a thermostat cable with 5 to 7 wires inside. And your control need to have the conventional terminals.  Please get me the model numbers of the indoor air handler and the outdoor condenser unit. 

AC Cooling Wizard

[HiEm]

Hi @CoolingWizard ,
Is my Trane AC/Heat compatible with Nest Thermostat G4CVZ? White is connected to D, Red is connected to R, Blue is connected to B. The green and yellow wires aren't connected to anything?

[CoolingWizard]

Your Trane is currently using a proprietary digital communications. It can be converted to conventional HVAC controls. You would re-wire the air handler putting red on R, White on W1, Yellow on Y1, Green on G, and Blue on B/C. On the nest thermostat you will use Red on R, Yellow on Y, Green on G, Blue on C and White on W. You need to locate the cable going to the outdoor unit, and move the red wire to Y1.  

AC Cooling Wizard

[Bjondahl]

Is my system compatible with a Nest Learning thermostat? I am getting an E105 error.

[jonatan686]

Hello @CoolingWizard  ! Would you please help me find out if my current thermostat can be replaced by the Nest thermostat?

Follows a picture of it and a link to the electrical diagram:

I think i have 1 Line wire (guessing black) wich goes through the on/of switch (from 7 in - 5 out) and a neutral (c wire guessing white) on 2.

  

Thanks a lot in advance!

[CoolingWizard]

@jonatan686 , your thermostat operation for 120 V line voltage. This is not compatible with a nest thermostat or any conventional HVAC thermostat.

[jonatan686]

Hello @CoolingWizard ! Thank you for the information! I found this data regarding my thermostat (RQ30) which says 250v. Still wont work?

Thank you

[CoolingWizard]

@jonatan686 , 

Unfortunately, no.  The conventional HVAC control systems use a step-down transformer to take wither 120V or 240v and reduce it to 24V for the control. This 24V is what is sent to conventional thermostats. Your type thermostat directly controls the full line voltage to your heating system. 

Now then, if your heart is set on going with a smart Nest Thermostat or the Nest Learning Thermostat, there may be a way. You would have to hav the system rewired. Now then, how far from your heating system is the Thermostat located? 

AC Cooling Wizard

[jonatan686]

Hello @CoolingWizard  Thank you so much for taking the time for explaining this to me. I'm actually really far away cause i live in a building with central heating system so rewirint it does not seems to be an option.

Thank you again for your help and time spent!

[Eric14]

 Hi I am wanting to check if the nest learning thermostat is compatible with my ac system. The letter in the far right covered by the red wire is a C.

[CoolingWizard]

@Eric14 ,

Hello, your far right red wire is RC.  Your system is a basic HVAC system.  The controls are as follows:

R/Rc/R is the 24VAC power.  This power is used to activate heating, cooling and the blower fan. 
Y/Y1/Y2 is the cooling compressor relay. 
W/W1/W2 is the Heating. This turns on the gas furnace or boiler. 
G is the indoor blower fan relay. 
O/B is the Heat Pump System change over valve control. Used only for heat pump systems 

C and sometimes B, is the 24VAC Power Common. 
 Your system can be supported by any if the Nest Thermostats models. 

AC Cooling Wizard

[jrcnj078]

Is This Compatible?

[jrcnj078]

This is heat only, gas furnace