Unlabeled wires in existing thermostat- need wiring help

[Jensy]

Hello. Trying to install my Nest thermostat (05/2021 model)

Wiring issues: current HVAC system is a ducted minisplit whole house system: Carrier 38MAQB18R-3 unit with thermostat (basically a wired remote?): Midea brand, model: KSACN0401 with 4 thin unlabeled wires (red, black, yellow, brown). How can I connect my nest thermostat using the existing 4 wires?

[Vin44]

Hi did you ever figure this out? Im having the exact same issue. Thanks!

[Jensy]

No. Nest is not compatible and their customer service is horrible and not useful. I was able to make it work with an Ecobee lite3 (the AC unit needed some sort of device installed by an AC company before it worked)

[Vin44]

Got it thanks for the reply. Ive spent hours trying to figure this out lol. 

[Vin44]

Btw how much did the AC company charge you to install the extra device to be able to make it work with a smart thermostat? Did it take them a long time to install also? Thanks again

[Jensy]

It was about $600, including the Ecobee thermostat, extra parts and labor. Expensive, but worth the money in savings on electric bills and able to control remotely.

[Margarine_D]

Thanks for reporting back on this.  Time to return my Nest.  Its a shame they don’t make an adapter, esecpaully now that these minisplit systems are becoming a standard in new installations in the US, and have been the standard in the rest of the world for years.

[Markjosephp]

Hi Margarine_D,

I'm sorry if you have to go through this. We'd like you to have a better experience, and I'd love to help.

A few questions: could you please tell us more about what's happening? Also, are you having issues installing your Nest thermostat?

Please let me know, as I would be happy to take a closer look and assist you further.

Best regards,

Mark

[Margarine_D]

Thanks. I have a ducted mini split HVAC system, with thermostat KSACN0501AAA, which is a pretty common unit.  

[Markjosephp]

Hi there,

Thanks for letting me know.

We're sad to see you go, @Margarine_D. We hope we can make it up to you in the future by using a Nest thermostat. Please feel free to let us know if you have more questions in mind.

Thanks,

Mark

[Margarine_D]

Thanks!  I would love to use a Nest, but they are not compatible with mini split / ductless / ducted and heat pump systems, as described above. 

This makes it challenging since all the new construction around me uses these kind of systems.

[EdwardT]

Hi Margarine_D,

Thanks for the help Mark!

@Margarine_D, I'm sorry to hear that your system isn't compatible with the Nest Thermostat. Let us know if you have other questions and we'd be glad to assist you.

Thanks,

Edward

[Jhonleanmel]

Hey folks,

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

Best, 
Mel

[Jhonleanmel]

Hi everyone,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.

Thanks,
Mel