Thermostat Wiring Diagram Colors. Finally, if that is not possible, then trace the wire out to the source. The common or c wire need not be run out to the thermostat however if the thermostat requires power the c wire should be routed to the thermostat.
It reveals the components of the circuit as streamlined forms, and also the power and also signal links in between the tools. Hvac systems with more functions need more wires to communicate to and from the thermostat. I recommend always to make note to which terminal each wire connects on the old thermostat before removing it.
Here is the industry standard thermostat wire color code used for most systems:
The wiring of your thermostat appears complicated, but when you understand the basic structure of it, including the terminals and thermostat wiring colors, it’s much less overwhelming of a task to install your own system. My thermostat has only two wires. The red wire or 24 vac power lead is connected straight to the rc & 4 terminals. It is better to take a good up close photo of the old thermostat and what terminals the colored wiring are terminated.