Tip & How-To about Heating & Cooling
There is a lot of confusion about terminal designations and thermostat wiring. There are no official standards for wiring colors, or even terminal designations for that matter. To be sure it’s always best to refer to your equipment manufactures wiring diagrams to see how their terminals are meant to be used.
As you can see in Part 1 the most common colors are the red, white, green, and yellow. These four colors are almost always associates with the same terminals. If you have any more wires than that you may have any number of combinations, depending on what the tech decided when they installed your unit. There is no right or wrong way to do anything. As long as the same wire is connected to the same terminals of the two pieces that they are running to and from, then the wiring is correct. It is up to YOU to verify and not just guess at what the installer was thinking.
It is always advisable to make sure that the power is off when working with electricity. Also when checking wiring and even as a good practice when working with your low voltage wiring, always install an automotive ATC fuse holder at the hot side of the transformer secondary. (Load side) This will protect the transformer in case you accidentally short it out.
I need to make sure that I give this caution. Please if you are not familiar with electric and wiring, do not attempt to work on your unit alone. Find someone that is comfortable in their ability to work with electricity. It is very easy to do more harm than good and even experience technicians make mistakes at times. Use every caution and work very methodically and carefully. Haste makes waste!!!
Posted by D. Floyd... on
Here is a tip that explains the wiring and the color designations...
Thermostat Wiring and Terminal Designations
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