Nest Thermostat wiring issue

[Abdurrab]

I would like to receive help; I have nest learning thermostat 3rd G, and I am not sure about the wiring lableing for the thermostat, the old thermostat which come with the Air Condistioner (General) Modle No; AOSA25FBTAH, there are only three wires connected to the thermostat; R, W, and B will it work out or do I have to get an extra wire from the indoor unit to the thermostat? 

Please Help! 

[Houptee]

Yes it should work fine.

Connect R to RH

W to W1

B to the Nest C (some brands call the C wire B)

[Markjosephp]

Hello there,

Thanks for helping, @Houptee.

@Abdurrab, I hope you've got the answer you're looking for. If you're still in need of assistance, feel free to let us know.

Regards,

Mark

[Abdurrab]

Still the diagram says there is no power in the wire c 

[Abdurrab]

 

[Abdurrab]

 

[Abdurrab]

 

[Abdurrab]

 

[Abdurrab]

 

[Houptee]

Is this a wall mount mini split type unit?

I see buttons for the air flow up down and left right. 

The Nest won't work for mini split systems if that's what you have. 

They have dedicated thermostats for them usually remote control.

Some brands have a interface device for mini splits to use other thermostats but you need to contact the manufacturer to find out if that brand makes one.

[Markjosephp]

Hello there,

Thanks for lending a hand here, @Houptee.

@Abdurrab, I'm checking in to make sure that you've seen Houptee's response. Please let us know if you have any additional questions or concerns.

Regards,

Mark

[Abdurrab]

Hi, Houptee, 

Actually it is a central AC from General, the wiring coming from the internal unit are three wires as you can see in the picture of original thermostat, R,W,and B, we have tried to apply your instructions but the Nest thermostat always keep saying that there is no power to common C. we also tried to change the wiring places in the Nest thermostat, unfortunatly the problem still there and we could not install it properly. 

your advice is highly appreciated! 

[Houptee]

Looks like the wires that go to the thermostat are ethernet cable like for computers.

I do not think a regular thermostat will work with this system it must send info on a data bus to the unit.

I could be wrong but I could not find any installation manual online when I searched for the model number. If you have the manual you could look up the thermostat wiring information. Sometimes if you take the cover off the air handler there is a wiring diagram decal on the back of the cover and it should show thermostat wiring info and notes.

[Jake]

Hey there,

Thanks for the help Houptee.

I wanted to check in and see if you managed to see Houptee's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

[Jake]

Hey there,

I wanted to check in and see if you are still in need of any help. Please let me know, as I would be happy to assist, and answer any questions you may have.

Best regards,
Jake

[Jake]

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake