Refrigeration for HVAC 101

Refrigeration for HVAC 101

Refrigeration 101 - Refrigeration and Air Conditioning Technology is a textbook and will help you follow this material.

You must understand heat and heat transfer principles and theory. That includes the fundamental physics of heat, including thermodynamics. If you have the recommended textbook, read Chapter One in the textbook (Refrigeration and Air Conditioning Technology). A technician needs to comprehend these principles and practice them as they ply the trade of refrigeration.

These fundamentals are necessary for a technician to fully grasp to be their best. By studying these principles and comprehending them, you will be able to solve problems and be the best at what you do. Whether you do installation or service, this knowledge will help you go further than those who have not studied and learned these fundamentals.

What is covered in this lesson: (more…)

Condenser Fan Motor Not Turning

Condenser Fan Motor Repair for a Goodman Heat PumpHeat Pump AC Condenser Fan Motor Not Turning - Both heat pumps and air conditioners use the process of refrigeration to provide heating and cooling. One of the major components of that process is the condenser. A major component of the condenser is a condenser fan motor. Furthermore, both air source heat pumps and air conditioners have a condenser fan motor. Is your Condenser Fan Motor Not Turning?

For an air conditioner, the condenser fan motor is used to reject heat. For a heat pump, the condenser fan motor both rejects heat and pulls air into the condenser coil to absorb heat. Finally, there are times when the condenser fan motor will fail making a repair necessary. (more…)

High Head Pressure Air Conditioner Heat Pump

What you will learn from High Head Pressure Air Conditioner Heat Pump


  • An essential troubleshooting list of things that cause high head pressure
  • What is high head pressure?
  • Condenser Fan Motors
  • Condensing Units and Condenser Coils
  • The Line set and crucial devices in the line set
  • Non-condensing gases in the system
  • Refrigerant overcharge
  • Design conditions and head pressure

High Head Pressure Air Conditioner Heat PumpHigh Head pressure for a refrigeration system, including a heat pump or air conditioner can cost you more money and possibly lead to premature failure of the compressor. It can also cause a malfunction in the system that will lead to reduced capacity for cooling and heat (for a heat pump) or the system not functioning at all.

For any refrigeration system, it is vital that all pressures, the suction, and the head pressures are normal and as designed for the load and outdoor ambient temperature.

Some of the initial and essential things to look at when troubleshooting high head pressure include the condenser fan motor working and operating at the proper RPM’s and clean condenser coils. More advanced things to look at include refrigerant overcharge and a restriction in the refrigerant lines. There some other things you can look at when a heat pump or air conditioner is experiencing high head pressure. (more…)

Heat Pump Leaking Refrigerant Question

Heat Pump Leaking Refrigerant QuestionHeat Pump Leaking Refrigerant - Is my Heat Pump Low on Refrigerant? I get this question a lot from both my customers and my site visitors. They tell me every year a technician comes out and pumps a few pounds of refrigerant into their unit and it’s good again for another year. A refrigerant leak for an air source heat pump is not uncommon. Or is it? Let us explore the question a bit further and see what really happens when you refill the unit over and over again, year after year. (more…)

Refrigerant R-410A Pressure Temperature Chart

Refrigerant R-410A Pressure Temperature ChartRefrigerant R-410A Pressure Temperature Chart - This R410A PT Chart will help you when charging a system that utilizes R-410A. Furthermore, R410A is an HFC and is commonly used in residential and light commercial HVAC equipment for air conditioners and heat pump systems.

Additionally, it widely replaces HCFC R-22 which was mandated by the Montreal Protocol to be phased out of production and use by 2020. R-410A differs a lot from R-22 in both chemical makeup and the tools needed to measure the pressures of R-410A. Since R-410A operates at a higher pressure and a different type of oil is used than R-22 separate gauges should be used to obtain pressures.

Lastly, it prevents cross-contamination of the oils can cause serious issues between the two types of systems and it is highly recommended to use separate gauges for service providers. (more…)

HVAC Triple Evacuation | Heating & Cooling Refrigeration

HVAC Triple Evacuation - There is definitely some confusion among HVAC/R technicians about the proper methods of evacuation. Evacuating before introducing the refrigerant to the refrigeration circuit.HVAC Triple Evacuation Let me be clear from the start that my methods of evacuating a refrigeration circuit are based on experience, education, and an official guide produced by the US Military and their specifications and proper procedures for evacuating a refrigeration system. It is very important to do a refrigeration triple evacuation properly the first time.

This is the proper procedure on any US Navy ship or support ship that a refrigeration system that has been open to the environment. It must be triply evacuated before the refrigerant is reintroduced to the refrigeration circuit.  The purpose is to prevent future problems because of contaminants including moisture in the system. (more…)

Frozen Evaporator Coils Troubleshooting Easy List

Frozen Evaporator Coils Troubleshooting - It was a very hot day and I got a ticket to respond to a call for no cooling. The customer said there was ice on the air conditioner. The heating and cooling service operator instructed the customer to turn the AC off so the ice could thaw before I got there to figure out the problem. It needs to be thawed before any AC troubleshooting can occur. There are two main causes why the evaporator coil will freeze and cause ice on the air conditioner. One is decreased or no airflow and the other is a low refrigerant charge.

For the first problem, you can likely repair it yourself quite easily for some of the cases. For example, on our list below, you can easily change a dirty air filter but I would not expect most people would want to change a bad blower motor. However, for the refrigeration problem, you need to call in a licensed HVAC technician to make the repair. A frozen evaporator coil was frozen for a reason and the ice only diminishes airflow even further making the air conditioner or heat pump totally useless for its intended purpose.

Proper Refrigeration Piping Installation Practices

Proper Refrigeration Piping Installation Practices – Installing a new air conditioning and heating system requires skill and knowledge of proper procedures in electrical wiring, controls wiring, and pipework. On commercial projects, a skilled electrician handles the electrical hookups, a controls technician handles the control wiring, and a pipe fitter handles the pipework, including the refrigeration piping, which can include chilled water and refrigeration pipework. (more…)