HoneyWell - 3 wires - to Nest - Compatibility Check

[Fco301]

I want to know if I can swap this old and nasty looking HoneyWell Thermostat for a Nest. A couple of things - I live in a high rise building, heat and cooling are controlled by the building so they switch it seasonally (super annoying for those random cold or hot days). Our unit can only turn up the heat and the fan. We have a separate control for just the fan speed...I know...weird. Attached are some pictures...support wan't able to help so I am hoping the community can shine some light. Thanks in advance!NO actual labels on cables 😞

[aatienza]

Hey Fco301,

Thanks for reaching out. We notice that your current thermostat has non-standard wiring labels (A,B,C). This means that you have a proprietary system. Proprietary systems aren’t compatible with Nest Thermostat devices. However, some proprietary systems can be rewired by a pro installer to be compatible. If you'd like to continue using a Nest Thermostat, you may reach out to a local pro first and have them check if your system can be rewired from proprietary to standard wiring system. Let us know if you have any other questions.

Best,

Archie

[aatienza]

Hey there,

Since this thread hasn't had activity in a while, we're going to close it to keep content fresh. Feel free to submit another post, and provide as many details as possible so that others can lend a hand.
 

Thanks,

Archie