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.

Hello everyone, my name is Piotr Kisiel, and I’m a student at HVAC Technical Academy. Today, I’m going to talk about the pump down procedure—what it’s used for and how it’s done.

Before starting the pump-down procedure, the condenser unit needs to run for about 10 to 15 minutes. This ensures the system is operating properly and that the compressor is functioning correctly.

Now, you may ask what the pump-down procedure is and why we need to do it. The pump-down procedure is used to recover refrigerant either into the condenser or to remove it from the system entirely. We typically perform this procedure when we need to open the system, such as when replacing a coil or changing a filter drier. Pumping the refrigerant down into the condenser is one of the fastest and most efficient ways to remove refrigerant from the rest of the system.

Here’s how it’s done:

First, run the system for 10 to 15 minutes. Then, close the liquid line valve, which is the high side valve. After that, monitor your gauges and watch for the low side pressure to drop.

When the low side pressure reaches approximately 0 PSI, close the vapor line valve and immediately shut off the power to the system. It’s important to shut the power off right away to prevent damage to the compressor.

That’s the pump down procedure.

Thank you for listening.

Hi Mrs. Smith, my name is Trong Son Huynh from HVAC Technical Academy. Today, I’d like to talk about the defrost board.

The defrost board is located in the outdoor unit. Its main function is to monitor the temperature of the outdoor coil.

When the temperature sensor on the coil detects that the coil has frozen and ice has formed, the defrost board will switch the reversing valve to cooling mode. This allows hot refrigerant to flow through the outdoor coil to melt the ice.

At the same time, the system temporarily shuts off the outdoor fan so the condenser coil can heat up more quickly. The defrost board also sends a signal to activate the heat strip in the indoor unit to maintain indoor comfort during the defrost cycle.

This cycle continues until the temperature sensor detects that the ice has melted. Once the coil is clear, the system switches back to normal heating mode.

When the defrost board goes bad, the heat pump system may fail to remove ice from the outdoor coil. This can lead to poor heating performance and excessive ice buildup.

Some common causes of defrost board failure include extreme temperature fluctuations and dust buildup. Dust and debris can affect the board and potentially cause electrical issues within the circuit.

That’s an overview of the defrost board and how it operates.