Orlandus Rivera HVAC Training Video | Jan 2026 Workshop

Hi, my name is Orlandus Rivera, and I’m here at HVAC Technical Academy. Today, I’m going to be talking about the thermostat, low voltage wiring, and the flow switch.

Starting with the thermostat, this is what we use to command the system. It controls your heating, cooling, and fan functions.

The low voltage wiring connects the thermostat to the air handler inside and the condenser outside. These wires carry the commands from the thermostat to the appropriate components, such as the blower motor, the condenser, or the reversing valve if it’s a heat pump.

Next is the flow switch. This is located on the secondary drain port of the drain line. It acts as a safety device or emergency shut-off for the indoor unit if too much water begins to back up.

If the drain line becomes clogged and water rises, the float inside the flow switch will lift up and shut down the system. If you notice your system turning on and off unexpectedly, you can check the flow switch to see if it has been triggered. Once the issue is corrected and the switch is lowered back into place, the system should turn back on.

Other reasons these components can fail include normal wear and tear over time. Wires can degrade, especially if they were installed improperly. Rodents can chew on wiring, and insects can get into connections and cause interruptions in communication between components.

And that’s an overview of the thermostat, low voltage wiring, and flow switch.