How to use a Nest to control a Carrier mini-split air conditioner?

February 7, 2017 7:57 PM

We have a carrier mini-split air conditioner (controlled with a remote control). We'd love to use a dedicated nest thermostat to control it. Is there any way to make this happen?

Some google results suggest there is an adaptor of some sort for mini-splits...but the URL for the adaptors is non-functional. Advice?

posted by arnicae to Grab Bag (4 answers total)

From a Nest employee on Reddit:

"The Nest doesn't work with most mini-split AC units. They normally use milivolt controls, and the Nest needs 24V."

I have found their support to be pretty good. You could contact them and ask about your specific unit.
posted by primethyme at 8:21 PM on February 7, 2017

Yep, but you'll have to get in line. I've had three Flair Pucks on preorder for about four months.
posted by supercres at 8:45 PM on February 7, 2017

It looks like Honeywell makes an adaptor.
You can buy it on Amazon.

It allows you to use a 24 volt thermostat, like the Honeywell T87F or apparently the Nest, with a 750 millivolt systems.

Note that you may also have to buy and install the 24 volt transformer, like the Honeywell AT72D, and the wiring to the NEST to provide that 24 volts that it craves unless you already have some abandoned or operational 24 volt HVAC thermostat wiring in your house.
posted by the Real Dan at 12:55 AM on February 8, 2017

Another option if you are willing to use a non-Nest controller is Air Patrol or one of a few similar products that emulates the AC units remote control.
posted by Lazlo Hollyfeld at 7:16 AM on February 8, 2017