Compatibility with nest thermostat

[Maralon]

Can someone help me and see if my system is compatible with the nest thermostat?

[Houptee]

Yes take a pic of existing thermostat wiring and tell us what kind of system you have.

Heat with AC or just heat? Gas furnace with ductwork or a boiler with hot water heating system?

[Maralon]

I’m not sure, it’s an Ac with heat and ductwork.

 

[Maralon]

Is it compatible or not?

[Houptee]

It should be compatible but I cannot read the markings for the wires.

Looks like Red is R

What are the next 3 wires labeled on the old T stat?

Is that a Orange wire? Those are usually for heat pump systems. Do you have a heat pump with AC?

White will go to W that's for heat (no jumpers needed on Nest)

Green goes to G that's for the fan

[Maralon]

Thank you for replying, it goes

Red with R

Orange with “O”

Blue with “C”

Yellow with “Y1”

white with “E/W

green with “G”

and then there’s another white cable that it’s connected to “E/W & W2”

also how would I know if I have a heat pump with A/C? Not quite sure about that.

[Houptee]

Heat pumps run the outside unit for Ac and heating. Basically the outdoor AC system runs in reverse so the refrigerant gas aka Freon flows backwards in heat mode to capture heat from the air outside and heat the house.

The orange O/B wire controls the reversing valve outside to make the unit switch to heat mode.

So connect the wires same as the old T stat to the Nest

R to R

O to O/B

Blue to C

Yellow to Y

Green to G

White to W (do not put any jumpers on Nest like the old tstat)

Then in setup tell it you have a Heat Pump with forced air ductwork

It should work that way. If not report back what it is doing.

[Maralon]

Thank you, what about the orange one? And Will it be needing the C wire adapter?

[Houptee]

Orange goes to O/B on Nest

Blue is your existing C put it on the Nest C so you should not need the adapter as long as the other end of the blue wire at the equipment end is actually connected to the C common screw.

You can verify using a multimeter set to AC volts (not DC) and put the red lead on Red wire screw on old Tstat, black lead on the Blue wire screw. See if you are reading 24 - 30 Volts AC.

If you are then congrats you have a C wire already.

[Jhonleanmel]

Hey folks,

We appreciate your help here, @Houptee.
@Maralon, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,
Mel

[Jhonleanmel]

Hey there,

Checking back in should you still have some questions here. Let us know by replying to this thread. 

Best, 
Mel

[Jhonleanmel]

Hi everyone,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,
Mel