Can't figure this 3 wire system out or find anything in postal about it

Air Conditioning Wiring Color Code

Carrier thermostat wiring color code Thermostat wiring wire heat color diagram pump air nest guide common goodman colors honeywell code labels heater aruf handler wires

Hvac wiring explained Can't figure this 3 wire system out or find anything in postal about it Wiring conditioning thermostat conditioner codes

Can't figure this 3 wire system out or find anything in postal about it

Hvac conditioner diagrams conditioning
Can't figure this 3 wire system out or find anything in postal about it
Can't figure this 3 wire system out or find anything in postal about it

Carrier Thermostat Wiring Color Code
Carrier Thermostat Wiring Color Code

Hvac Wiring Explained
Hvac Wiring Explained