HVAC Technical Academy
Sanford, Florida
September – October 2026 Session

Hi, my name is Vernon. We’re here at HVAC Technical Academy. Doing a great job with teaching everyone and giving us the proper knowledge and guidance.

Today I want to talk to you guys about low voltage wiring. It’s a big major component of the HVAC system. So here in my hand I got some thermostat wire. This is the low voltage wiring we’re talking about in the HVAC system.

They carry 24 volts from the transformer which the transformer steps it down from 240 volts to 24 to be able to send the 24 volts out to the other components. With these wiring so far the general basic like understanding of these wirings.

So starting off with blue would be your common. Red would be your 24 volts or your power. Green would be your inside air handler air air handler blower motor. Yellow would be going out to your outside unit to the contactor which would initially turn on your compressor and your condenser fan motor. And then we have a white that usually goes into the heat strip or your W terminal.

With these wires we’re able to communicate or send some type of controlling signal towards the other components to be able to run it properly. Say there was an issue with one of these wires. Say that you had some landscapers come by for the day. They cut the grass. Unfortunately one of the weed eaters end up clipping one of your wires. They may have clipped one of these or clipped all of them. You never know until you go to check them.

But a way to to test to see if they did clip a wire with would be able to get one of your multi-meters. We would set it to the MFD setting on here. And then we’ll set it first select to get it over to the continuity. Once you get the continuity, that’s where you test the resistance. Basically it’s showing if your wire is able to pass voltage or pass current. If it was snipped or cut, then it would definitely not be able to pass the current.

Starting off to make sure my voltmeter is working properly, I would test it by just touching each other. And once I hear that beep, it’ll come up with a an amount as well or a reading. And then that’s how we know that we have continuity. Say right now I could test common. I’ll test it on both ends. And I got a reading and a sound, so I do have continuity. In the event that the landscapers did come by and snip your wire, you wouldn’t get any reading or any indication of a sound with that wire. That’s how you would know if the wire is broken.

And I believe that’s all I got right now on the low voltage wiring. So I do want to thank you guys for taking the time to watch my video. And I do hope that you guys do take a chance to come out and have a good chance at testing your low voltage wiring as well. So