Types of thermostat wire. The most common is 185 5 strand 18 gauge.

1990 Ac Wiring Diagram Diagram Base Website Wiring Diagram
Hvac wiring diagram colors. Finally this way you can match up the appropriate wire color coming from the thermostat to what it controls in the equipment. In either case it is crucial to find the wiring diagram for the unit. It is better to take a good up close photo of the old thermostat and what terminals the colored wiring are terminated. Basic thermostat wiring colors air conditioner systems always remember when changing a thermostat for a new thermostat to take a photo of the colors and where they go on the old thermostat or get a pencil and paper and write it down. The 5 strands of wire provide enough functions for the modern. This video is part of the heating and cooling series of training videos made to accompany my websites.
There are a variety of thermostat wire types. Hvac systems with more functions need more wires to communicate to and from the thermostat. I explain what each of the letter terminals are for the voltage path how it works and also the normal color code used. I discuss how to wire the contactor and what the difference is between the. O orange wire to the o terminal for the reversing valve altough a few manufacturers use the b terminal for the reversing. R red wire to the r terminal g green wire to the g terminal y yellow wire to the y terminal w white wire to the w term.
The main difference setting each apart is the number of colored wires. C blue wire to the c terminal sometimes you will this. What the color code means for air conditioner and furnace thermostat wires. The red wire should always come from the hot side of the 24 volt transformer.