When checking your HVAC system for maintenance, it is inevitable to deal with its complicated electrical wirings and codes. And if you are not comfortable with working around electrical components, it is therefore crucial to understand at least its basics. Knowing the fundamental codes of your electrical system may help protect you and your family from any possible dangers that may result from a faulty wiring.
Before you start working with the system, the most basic prevention you need to do is to turn off the main power that supplies your HVAC with electricity. This may either be a circuit or a fuse found in the unit. Some systems also store electricity that may need to be released appropriately.
The detailed codes below may help you decipher even a bit of the complex thermostat wiring of your system.
The red (R) terminal in the system powers the hot area of the transformer, the yellow (Y) one is designated for the compressor function, the white (W) wire is for heating. Meanwhile the green (G) terminal powers the furnace blower. Also common wirings in the system are the orange (O) wires that energize heat and the blue (B) wires for the cold.
Other common terminal colors also include the optional blue, tan, pink or gray ones (E), allocated for the emergency relay on heat pump. The gray or tan (T), on the other hand, is for outdoor reset of the anticipator. In addition, there is also the terminal that comes in pink or other color (W2) for second phase of heat, which is often correlated to pink (W) or blue (Y2) for second phase compressor. The blue, brown, tan or gray (L) wires are assigned to power the indicator service lamp.
These are only a few fundamental wiring codes found in a typical thermostat. Some manufacturers however, may have certain wiring codes that may be different. Nevertheless, this basic knowledge on the electrical system can greatly help put you on a good start when checking for problems in your system.