Which saturation temperature scale should be used for R-407C evaporator calculations?

Use the dew-point saturation temperature for evaporator superheat calculations with R-407C.

Does high outdoor humidity reduce an air-cooled condenser’s heat rejection?

Not directly. Air-cooled condensers are affected mainly by outdoor dry-bulb temperature and airflow, not humidity.

How much heat does a 20 A, 460 V compressor motor add per hour?

Approximately 31,400 BTU/hr, calculated from 20 × 460 × 3.412; actual input depends on power factor and system configuration.

Free online course HVAC training

Duration of the online course: 4 hours and 1 minutes

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Build job-ready HVAC skills fast with this free online course—master refrigeration cycles, psychrometrics, and smarter diagnostics, plus a certificate option.

In this free course, learn about

Definition of HVAC and major system types (heating, ventilation, air conditioning, refrigeration)
Primary job of an A/C: remove heat and moisture from indoor air and reject it outdoors
How outdoor humidity affects (and mostly doesn’t) an air-cooled condenser’s heat rejection
Refrigeration cycle fundamentals: compression, condensation, expansion, evaporation (Part 1 & 2)
Key measurements affected by indoor load and how hot pull-down can mislead charge decisions
Using psychrometrics in HVAC: air properties, moisture content, enthalpy, and comfort implications
Two most-used field psychrometric readings: dry-bulb temperature and wet-bulb/relative humidity
How to select the correct R-407C saturation scale for evaporator work (dew vs bubble point)
Calculating compressor motor heat added to the system from electrical input (V, A to BTU/hr)
Centrifugal chiller refrigeration cycle basics (Trane-style) and major components/flow paths
How an economizer improves centrifugal chiller performance and what changes in the cycle
York YCIV chiller cycle features, including flash-tank/ economizer operation
How to identify low refrigerant charge symptoms on YCIV/YVAA flash-tank systems

About the free online course

Step into the HVAC field with a practical foundation that helps you think like a technician, not just memorize terms. This free online course is designed for anyone who wants to understand how refrigeration and air conditioning systems really work, how to read the signals a system gives you, and how to make better service decisions in real-world conditions. Whether you are exploring a new trade, adding a valuable skill to your toolbox, or aiming to boost your employability, you will gain knowledge that translates directly to day-to-day HVAC work.

You will start by clarifying what HVAC is and what an air conditioner is truly meant to do inside a building. From there, the course builds your understanding of the refrigeration process step by step, connecting the purpose of each component to the movement of heat and the behavior of refrigerant. Along the way, you will learn how environmental and operational conditions influence performance, including how humidity and heat rejection affect system efficiency and how indoor load can distort the measurements that technicians often rely on when evaluating charge during a hot pull down.

The course also strengthens one of the most useful diagnostic skill sets in the trade: psychrometrics. By connecting temperature and moisture measurements to comfort and system operation, you will learn to interpret common field readings with greater confidence and avoid assumptions that lead to callbacks. You will also tackle refrigerant-specific thinking, such as properly using saturation scales with blends like R-407C, so you can approach superheat and saturation with the right mindset.

To round out your skills, you will explore chiller operation through real refrigeration cycle examples, including centrifugal systems and the impact of features like an economizer. You will also develop diagnostic awareness for scenarios such as identifying low refrigerant charge in flash-tank systems, helping you move from symptom spotting to cause-based troubleshooting. By the end, you will be better equipped to discuss HVAC concepts clearly, interpret measurements more accurately, and approach refrigeration and air conditioning problems with a structured process.

Course content

Video class: What is HVAC? P1 Refrigeration Refresher for HVAC Technician 19m
Exercise: What is the primary job of an air conditioner in HVAC?
Video class: HVAC Training: What is HVAC? Part 2 20m
Exercise: Does outdoor humidity affect an air-cooled condenser's ability to reject heat?
Video class: HVAC Training: What is HVAC? Part 3 41m
Exercise: Which measurement is most affected by indoor load and can mislead charge decisions during a hot pull down?

Video class: Refrigeration Cycle Part 1 - HVAC Training 33m
Exercise: R-407C: Which saturation scale is used for the evaporator?
Video class: Refrigeration Cycle Part 2 - HVAC Training 17m
Exercise: How many BTU per hour does a compressor motor add if it draws 20 A at 460 V?
Video class: Psychometric's in Refrigeration 35m
Exercise: HVAC Psychrometrics: Which two readings are most commonly used in the field?

Video class: Trane Chiller Centrifugal Refrigeration Cycle 43m
Exercise: Effect of an economizer on centrifugal chiller performance
Video class: York Chiller Refrigeration Cycle - YCIV 30m
Exercise: Identifying low refrigerant charge on YCIV/YVAA flash-tank systems

Learn aboutHVAC Training

Explore free online HVAC training courses designed to help beginners and professionals build practical skills in heating, ventilation, air conditioning, installation, maintenance, troubleshooting, and safety. Learn at your own pace, improve your career prospects, and earn a certificate with every free HVAC course you complete.