Joey Henderson, a member of the iConnect Training tech team, gives instructors insight into teaching future technicians using the TU-106 Dual Application Refrigeration Training System.
Here are 5 HVAC lessons every instructor can implement in their curriculum:
Lesson #1: Go over every component of the system
Students should be able to identify and define each component of the system including:
- Oil separator
- Condenser coil
- Medium temp evaporator #1 and thermostat
- Low temp evaporator #2 and thermostat
- Heat exchanger
- Liquid line solenoid valves controlled by each of the thermostats
- Flow meter that actually shows you the flow rate of the refrigerant in each coil
- Sight glasses on all coils that are going to show the change of refrigerant flow through the system
- Dual pressure sensor both low and high
- Defrost time clock
- Biflow filter drier with sight glass
- Defrost temperature fan delay and heaters for defrost
Lesson #2: Explain the entire refrigeration cycle through the system
Have students visually work their way through the entire system. They can start with the high pressure discharge gas coming out of the compressor and follow it through the system. They’ll see the pressure changes in the gauges and the sub-cooled liquid coming out of the compressor.
Lesson #3: Run the system using a single or dual evaporator
With all the training knobs on the unit, instructors can actually isolate different meter devices and different coils. So, they can show students how the system can be run using the isolation valves as either a single evaporator or dual evaporator.
Lesson #4: Use different valves to perform different functions
There are multiple valves on this training unit including the automatic expansion valve, thermostatic expansion valve and the capillary tube. Each of these valves simulates refrigerant flow through each metering device. With these valves, instructors can choose which one they want to show to the students.
Lesson #5: Add a 4th metering device
There’s an access port where instructors can add in a 4th metering device of their own. It could be a different length of capillary tube or another expansion valve that would have a restriction inside.
Lesson #6: Troubleshoot the defrost time clock
Show the students an actual working defrost time clock. Let them wire it up and then troubleshoot it.
Lesson #7: Create an airflow scenario
Play with air flow and adjust it to see the dramatic difference the changes make with pressures in temperatures. Pose this question to students, “what do you think will happen if we start losing airflow on the evaporator coil?” Then, let them work through it and see what they come up with. Once show them what it really does.
Remember: As an instructor, the only limitation is your imagination!