How to wired with GH,GM(OB),GL

[Kenwong]

Anyone can help?

My system is a multi speed fan system, how to wire them 4th gen?>

[GabrielaG · Accepted solution]

Hi Kenwong,

Thanks for reaching out to the community. I understand that you have a multi-speed fan system, and you want to know how to wire GH, GM, OB, and GL to the Nest Thermostat 4th gen. I'll do my best to help you right now. 

To provide you with accurate information, please help me by sending me a picture with the wiring of your current thermostat.

I'll be waiting for your response; please let me know if you have any other details that could be useful. 

Regards,

Gabriela

[Kenwong]

 hi

thanks for ur replying, my original thermostat wiring was as below?

blue - GH

Orange- GM/OB

Green to GL

Black to C

white to W

yellow to y

red to R

This is how it connected to the original thermostats form the condo developer. But i purchased once of the 3rd gen nest, and tried to wire it with my system, but the google help center agent said my system is not compatible with 3rd gen , so i called my building technician to come over and check . but he told me he made a little change on the circuit control board, which is set the fan AUTO only ,so my 3rd GEN was working well. after days later, since the 4th gen on sale i purchased one , and now google agent said my system is not compatitible with 4th gen , allways ask me to find a nest pro which i need to spend more money for a thermostats, but ecobee wont have this happen , they will just gimme the wiring diagram which google wont ,so am i neccessory to get a nest pro ?plz helpl as so as possilble , no heat runnning in my place