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  • It Has a Flat For a Reason
  • Motor Speed – The Basics
  • Understanding Relays With the 90-340
  • Heat Doesn’t Rise
  • The Basic Residential Maintenance for a Heat Pump / Electric System
  • Technician Head Trash
  • Why the New Guy Gets Fewer Callbacks
  • Why is 240V called “Single-Phase”?
  • Flowing Nitrogen? Make Sure You Purged First
  • What is a GFI?
  • Laws of Energy and Matter
  • Condensate Switch Controversy
  • Does Mass or Volume Move Heat?
  • Avoiding and Eliminating Callbacks
  • Why Compression Ratio Matters
  • Better Temperature Measurements
  • How to Make Better Decisions
  • Uncommon Start and Run
  • Gas Law Concepts for HVAC/R
  • Why Measuring Static First Isn’t Always Productive
  • Pre-Cleaning Copper
  • Receiver Basics
  • How to Reduce Indoor Humidity
  • How to Eliminate Surprises on Install Jobs
  • Sight Glass / Moisture Indicator
  • Lockout/Tagout (LOTO) Basics
  • Properly Deburring (Reaming)
  • What is the Difference Between ACH & ACH50?
  • Which Valve Do I Open First?
  • The 1/7 (or 1/10) Rule for Oxy-Acetylene Torch Tips
  • Evaluating HVAC Tape Performance Under High Heat and Static Load (Part 1)
  • Oxy-Acetylene Torch Tips and BTUs
  • Compressor Mass Flow – Some Thought Experiments
  • Using the Socratic Method to Meet Trainees Where They’re At
  • Storing Food for Flavor and Safety
  • Stay On Your Game During Summer Service Calls
  • Parallel Circuit Resistance 
  • When Fear Gets On the Truck With You
  • Techs are Under Pressure
  • Careful With Cleaners
  • Does Setpoint Lead to Freezing?
  • Fan Blade Shroud Depth
  • The “Bad” Contactor That Wasn’t
  • How Private Equity Has Been Shaping the Industry (and How to Navigate It)
  • So You Want to Be a Space HVAC Tech
  • Testing, Recovery, and Charging a Sealed System
  • Flash Gas
  • What You Know About Start Winding Inrush Current Might Be Wrong
  • Making a Flare – Quick Tips
  • What’s the Scoop on PM10 and PM2.5 Particles?
  • Negative Superheat? Time to Check Your Tools
  • Setting & Checking Charges in the Rain
  • 8 Tips for New Techs (So You Don’t Get Fired)
  • Top Residential A/C Maintenance Tips
  • Beware of “Ghost” Voltage
  • How Moisture Moves
  • Maintenance During Major Repairs
  • Does a Motor Draw More or Less at Lower Voltage?
  • Battery-Integrated HVAC Systems: The Concept of Load Shifting with Built-in Storage
  • Decoding Windows: Frame Types, Low-E Glass, and How They Affect HVAC
  • Understand Dew Point and Absolute Moisture, The Right Side of the Psych Chart
  • 5 Things to Consider When Maintaining a Commercial Package Unit
  • Common Concrete Anchor Fails
  • Old Books
  • A Common-Sense Look at Temperature Conversions
  • The EPA’s 15-Pound Refrigerant Threshold in 2026
  • Key Takeaways From the 7th Annual HVACR Training Symposium
  • How Attic Designs Need to Account for Heat and Moisture
  • Motor Overheating
  • Attic Equipment Codes
  • Thermal Balance Point vs. Economic Balance Point
  • A Field Guide to Conductors for HVAC Techs
  • Ohms/Continuity Basics
  • That Rusty Coil/Galvanic Corrosion
  • Don’t Squeeze a Radiant Barrier
  • Do You Replace the Contactor and Capacitor With a New Compressor?
  • 3 Bad Techs Who Don’t Know It
  • 5 Simple Service Valve Tips
  • Wide, Narrow, Wide Diagnosis
  • How (and Why) to Flow Nitrogen While Brazing
  • Checking Evaporators on Furnaces
  • Three Steps to Deliver a Trades Education Talk
  • HVAC Ghosts of Christmas Past, Present, and Future
  • Upgrading Time & Temperature Defrost with Demand Defrost for Heat Pumps
  • Coil Temp Sensors: Thermostats vs. Thermistors
  • Cabinet Leaks in Air Handlers & Fan Coils
  • Planning and Installing Condensate Drain Lines
  • Tandem Compressors and Their Efficiency Benefits
  • Why the Breaker Size May Be Lower than the MCA (and Why That’s NOT Necessarily a Code Violation)
  • Set Inverter Technology Up for Success in Humid Climates
  • Why Airplanes Fog Up Before Takeoff
  • Why the Sauna Feels Hotter When You Throw Water on the Rocks
  • Silicon Carbide vs. Silicon Nitride Hot Surface Ignitors (HSIs)
  • The Many Uses of Thermal Imaging Cameras in HVAC
  • Replacing an Evaporator Coil
  • Different Ignitor Types and How They Work
  • The Enemy of My Enemy Is My Friend
  • The VOCs Lurking Under Your Customers’ Sinks (and In Many Other Spots)
  • Proper Liquid Line Drier Location
  • Gluing Tubing Insulation
  • Another Ob-NOx-ious Combustion Product
  • Drains and Double Traps
  • How to Replace a Condensing Fan Motor
  • Don’t Get Depressed (Unless You’re a Core)
  • Design and Performance Challenges of Air-Source Heat Pumps Across Diverse Climatic Conditions
  • Brownouts and How They’re Killing HVAC Equipment
  • CAT Ratings on Electrical Multimeters
  • AHRI Performance Data vs. Manufacturer Expanded Performance Data (and When to Use Each)
  • Field Guide to Crankcase Heaters
  • What Makes a Thorough Comfort Consultation
  • Compressor Failure: Diagnosis and Replacement Checklist for Residential and Light Commercial Equipment
  • Scroll Compressors in a Changing Regulatory Landscape
  • Ducting Ventilating Dehumidifiers
  • Measuring RTU Curbs with Adapters in Place
  • Voltage Protection Devices
  • HVAC in Nuclear Emergencies
  • A2L Refrigerant Sensors: Understanding False Alarms from Off-Gassing
  • Refrigeration Communication Troubleshooting Using Oscilloscopes
  • Preventing Heat Illnesses in the BLAZING Summer Heat
  • What is RS-485 Communication?
  • A2L Dissipation Boards and Leak Sensors
  • Oscilloscope Systems and Settings
  • I’ve Done It This Way for 20 Years – And That’s the Problem
  • Oscilloscopes 101
  • Estimating Made Easy with Unity Build
  • Buck-Boost Transformers
  • 32°F Saturation (Evaporator Temperature)
  • Upgrading a Single-Pole Contactor with a SureSwitch: Using a Wiring Diagram
  • Refrigerant Recovery Cylinder Fill Calculations Simplified
  • A Liquid Line Solenoid and What it Does
  • Confirming Liquid Levels with a Little Thermodynamics
  • Léon Creux’s Scroll Design: From Initial Failure to an Enduring Legacy
  • Traditional & Desiccant Dehumidification and When to Use Each (or Both)
  • Switch Terms
  • Piston Design and Bypass
  • Size and Orientation of Return Grilles and Supply Registers
  • How to Diagnose a TXV Failure
  • Checking Disconnects
  • 5 Capacitor Facts You Should Know
  • Discovering Mental Reference Points
  • Three Levels of Acid Testing
  • C Stands for “Common Mistake”
  • Dedicated Dehumidifier vs. Electric Reheat Dehumidification – Who Ya Got?
  • The Misunderstood Lockout Relay
  • HH vs. EK Filter-Driers: Technical and Field Comparison
  • ECM, VFD, and Inverter – What’s the Difference?
  • Work Vehicle Entropy
  • What Should My Superheat Be?
  • This is Not a Soft Start
  • 3 Ways to Reduce Compression Ratio in a Heat Pump
  • Best Practices to Conserve A2L Refrigerants in a Shortage
  • Wet Bulb and Enthalpy – The Left Side of the Chart
  • High-Pressure vs. Low-Pressure Shell Scrolls: A Deeper Dive
  • Should the Float Switch Break R or Y?
  • Watch Out for Fire Sprinklers
  • Don’t Drive Drowsy
  • Flex Ducts: Peeling Back the Layers
  • Solving Delta T
  • Don’t Fall for Unsafe Practices: Heights in HVAC
  • Why is 3/8″ Liquid Line So Common? – Liquid Line Sizing
  • Is a Smaller Suction Line OK? – Suction Line Sizing
  • Air Changes Confusion
  • Non-Invasive Testing: A Smarter Approach to System Diagnostics
  • What is Fenestration and Why Do I Care?
  • Introduction to SORIT Valves
  • Does Voltage or Amperage Kill You?
  • Short Circuits
  • Refrigerant Charging Basics For Air Conditioning & Heat Pump Systems
  • Solving Superheat
  • Inches of Water Column
  • Indirect Soldering Technique
  • Does Air or Nitrogen Absorb Water?
  • Why A/C Systems Freeze
  • Living in a World of Acids (and why HVAC coils are secretly crying for help)
  • HVAC/R Refrigerant Cycle Basics
  • Shielded Control Cable & Communicating Controls
  • AHRI Ratings Are Not Design Conditions
  • Valve Core Removal Tools
  • “White Shirt Techs – Manifesto” in Practice
  • 3-Phase Motors—The Basics
  • A Tale of Two Latents
  • Solving Subcool
  • Contactor Alternatives and Upgrades
  • Flex Ducts – Best Practices
  • What is a HSO (Non-Bleed) TXV/TEV?
  • Grit and Grace of the Die-Hard Tradesperson
  • Understand Heat Pumps
  • Using Heat & Nitrogen In Vacuum
  • Gas Pool Heater Components and Common Issues
  • The Chemistry of Combustion In the Wild
  • Why Discharge Line Temperature is a Useful Reading
  • Electric Heat & Blower Interlock
  • Heat Pump Defrost Troubleshooting Tips
  • What Should My Subcooling Be?
  • Isolation Diagnosis
  • Michael Faraday: Patron Saint of HVAC Technicians
  • Blower Fan Watt Draw Considerations for ECMs
  • Tool Selection: Electrical Meters
  • Tool Selection: Combustion Analyzers
  • Tool Selection: Manometers for the Right Job
  • Condenser Fan Blade Placement
  • Tool Selection: Analog vs. Digital vs. Probes
  • Two Ways to Prevent Freezing in 90%+ Furnace Condensate Lines
  • Decoding Measurement Lingo
  • History of Thermometry and the Invention of Thermometers
  • Three-Phase Voltage Imbalance
  • The Difference Between Variable-Speed and X13 Motors
  • It’s All Relative… Humidity
  • The Heating Sequence of Operations and Onions
  • Electronic Expansion Valve Troubleshooting
  • The Best (and Worst) Ways To Duct a Dehumidifier
  • Ramping Your Team Up for CO2
  • The Evolving Career of the HVAC Contractor: Embracing Change to Stay Ahead
  • Bernoulli’s Principle
  • How To Do a Heat Maintenance That Actually Matters
  • Technology Trade-offs
  • HRVs and ERVs in Commercial Buildings
  • 3 Tips for Training Apprentices
  • Not All CFM Are Created Equal
  • 3 Things to Check When the Unit Won’t Keep Up
  • Drain Trap Depth and Negative Pressure
  • Observations from the Field: Insights Gained from HVAC Ride-Alongs
  • R-454B vs. R-410A Side by Side
  • Crane Considerations for RTU Installation
  • Fresh Air in Commercial Buildings: Economizer Sensors and Settings
  • 8 Reasons Why Teamwork is Important in HVAC
  • The Limitations of Diagnostic Charts
  • Axial, Radial, and Digital Scrolls
  • The Extension Cord Puzzle
  • Wet-Bulb and Dry-Bulb Temps in HVAC Service
  • Equipment Sizing and Airflow in Different Markets
  • Short Cycling
  • Universal Condenser Fan Wiring Options
  • New A2L Refrigerants – “Easy as ABC”
  • Combustion Testing Doesn’t Stop in the Summer
  • Reviving History: Upgrading an 80-Year-Old Steam Boiler in Portland, Maine
  • The HVAC Technician’s Guide to Ensuring Comfort: Lessons from a Real-World Experience
  • OK, But How Do I Actually “Do” a Manual T?
  • Which Hose Do I Use?
  • Diagnosing ECM & X13 Motors
  • My Dad Changed HVAC & Me
  • Realistic Summer Triage Strategies
  • 3 Bad Reasons To Work Overtime
  • Mounting the TXV Bulb
  • Setting and Adjusting Superheat on a TXV System
  • Kitchen Exhaust and Makeup Air
  • Equipment Changes, Ducts are Forever
  • Brazing in TXVs: Best Practices
  • Make Plenum Pressures Work for You
  • Deploy Industry-Standard Training in YOUR HVAC Business
  • 5 Takeaways from Manual T
  • The MAD Room
  • TXV External Equalizers and Distributors
  • Troubleshooting Water Leaks
  • The One Duct Leak You Didn’t Expect
  • Static Pressure, Manometers, and Magnehelics
  • HVAC Moneyball: Could It Work?
  • Vacuum: Moisture vs. System Leak
  • One Way to Picture Superheat and Subcool
  • When Ducts Get Too Big
  • Six Tips to Help You Write an Article for HVAC School
  • Capacitor Testing and Replacement Procedure
  • Where Should the Float Switch Go?
  • Should I Pump Down or Recover?
  • Soft Lockout vs. Hard Lockout
  • Size Matters — Industrial “Shortcomings”
  • Learning Outside the Box
  • Making Duct Systems Work
  • To Glass Ceilings And Those Who Lend Us Their Hammers
  • Angry Air
  • Good COP – Bad COP
  • How to Properly Size a Dehumidifier
  • How Similar Are A2Ls to R-410A?
  • Two Tips for Tough Vacuum Jobs
  • Is Value Perceived?
  • What to Do with Your Micro-Manometer
  • Ventilation Strategies: ERVs, Dehumidifiers, and More
  • HVAC/R in 2024 & Beyond
  • Manual J Field Data: Ducts
  • The HVAC/R Island of Misfit Toys
  • How Do Communicating Systems Work?
  • The Ups and Downs of High-Performance HVAC
  • R-410A Phase-Down Update
  • Manual J Field Data: Windows
  • Gratitude and Reflection
  • Troubleshooting 90%+ Gas Furnaces
  • Weighing Refrigerant In and Out
  • Practical Uses of Combustion Analysis
  • Solving Comfort and IAQ Issues in a Vintage Home: A Case Study
  • Manual J Field Data: Floors
  • 5 Terror-Inducing HVAC/R Stories & Facts
  • The Case for Buying a Combustion Analyzer
  • Manual J Field Data: Walls
  • The Wide-Narrow-Wide of Manual J
  • Info For Homeowners About Heat Pump Defrost
  • Callback Prevention: Electronic Leak Detection
  • Scroll Compressor Pump Down, Megohm Test & Fusite Terminals
  • Oil Best Practices for HFC and HFO-based Systems
  • Glide at Static Pressure
  • Sizing Return Grilles
  • Under Pressure
  • Refrigerant Recovery Practices
  • What Airflow Goes Around HAS to Come Around
  • Common Causes of Compressor Failure
  • Training: Processes or Apprentices?
  • Sales: Techniques or Values?
  • How to Set a Charge by Superheat
  • Troubleshooting with DTD
  • Is R22 legal to use?
  • Does your Kitchen Exhaust Suck?
  • Improving Humidity Control on the Cheap
  • Where Do I Measure Delta T?
  • Equivalent Length Merry-Go-Round
  • What Changes Will You Soon See With the Shift to A2L Refrigerants?
  • Plenum Takeoffs Best Practices
  • Residential AC Maintenance Process
  • Understanding 240-Volt Circuits
  • Replacing Residential HVAC Equipment With “Predictable Results”
  • Thermal Balance Point
  • Build a Better Internal Training Program
  • Manual D Speedsheet Walkthrough
  • Maintenance Upgrades That Don’t Cost Your Soul
  • Why is the Air Dry at Altitude?
  • The Strange Behavior of Moisture in Stuff
  • Impacts of Decreasing Evaporator Airflow
  • Surge Protector Facts
  • Principles Of Troubleshooting: Seeing the Big Picture
  • Condensate Drain Codes & Best Practices
  • Homeowner’s Guide to Sizing an AC System (and who is responsible when you’re uncomfortable)
  • Diagnosing a Reversing Valve
  • Understanding “P” Traps in Refrigerant Lines
  • Troubleshooting Inverter Boards
  • Air Barrier vs. Vapor Barrier vs. Insulation
  • Gas Furnaces – What a Tech Needs to Know
  • Dunning-Kruger in HVAC
  • A Great HVAC Training Solution
  • Do Small Air Leaks Matter?
  • Why Many Techs Confuse Overload, Short, & Ground Fault
  • Don’t Forget the Suction Filter Drier
  • Combustion Air
  • Tips for Server Room Conditioning
  • Furnace Air Temperature Rise
  • A Story We Know
  • Gas Furnace Maintenance Procedure
  • The Diagnosis Game (and Why Van Sleeping Bothers Me)
  • The “Approach” Method of Charging and Condenser Efficiency
  • Retrofitting Existing R-404A/R-507A Systems
  • Is it too cold to set the charge?
  • A REALLY Loud Compressor
  • 4-20ma Control Basics
  • Pool Heater Water Flow Issues
  • Giving Thanks for the Hard Stuff
  • Infrared vs. Heated Diode Leak Detectors
  • 4 Reasons NEVER to Make Excuses
  • Potential for Good and Evil (The Hard Start & Potential Relay)
  • Infrared Thermometers Can Cause Confusion
  • The Dangers of Discounts in HVAC/R Businesses
  • Heat Pump Defrost Boards and W2
  • Combustion and Confined Spaces
  • The MOST IMPORTANT Skill a Tech Can Have
  • Heat Exchanger Crack Diagnosis
  • Crankcase Heaters
  • What You Need to Know About Microchannel
  • Refrigerant Basics
  • Condenser Coil Cleaning Step by Step
  • 4 Silly Mistakes of The New HVAC Tech
  • What is a Micron?
  • Piston vs. TXV Metering Devices
  • Why is the Breaker Tripping?
  • What does “RES” mean on a contactor or relay?
  • The Unexpected Result of Series Circuits
  • The Friction Rate Chart (and What it Means)
  • Low Airflow – Beyond the Obvious
  • Hit Your Spots
  • Moving Forward with A2L refrigerants
  • Switch Voltage
  • Adiabatic Cooling, Blower Settings, and Why You Care
  • Exposed Duct High Temperature Limit
  • Air Filter Static Pressure Drop
  • What is Flux?
  • Finishing Trade School? Some Things you Need to Know
  • Start Flowing Nitrogen Sooner
  • Fancy Refrigerant Words
  • The Impact of Adding or Removing Water From Air
  • The Sneaky Effects of Radiant Heat Transfer
  • Mistakes in Measuring Ohms
  • Tips for Managing Millennials and Zoomers
  • Unapologetically a Technician
  • Why and How to Adjust a TXV/TEV
  • How much PRESSURE is that Recovery Tank Designed For?
  • Something to Watch For When Replacing a Thermostat
  • Refrigerant Oil Basics
  • The Secrets to Happy HVAC Customers
  • Diagnosing and Finding a Refrigerant Restriction
  • Control Voltage Overamp – The Less Usual Cause
  • What is Enthalpy?
  • Electronic Leak Detection
  • Pull The Condenser Top
  • How to Use an Adjustable (Crescent) Wrench, Pipe Wrench and Tongue & Groove (Channel Locks) Wrenches
  • What are Dry and Wet Contacts?
  • Non-non-condensables
  • What’s So Wrong With “Beer Can Cold”?
  • Condensation – It Isn’t Where Hot Meets Cold
  • Changing Refrigerants and Why it Matters to You
  • Coil Cleaners: A Guide to Which Cleaners to Use in Various Applications
  • Does Refrigerant Get Old or Wear Out?
  • HVAC/R Brazing Indicators
  • Cooling Capacity Isn’t Always What it Seems
  • Use Static Pressure Responsibly
  • What Tradespeople Can Learn from Underdogs
  • Charging Systems with Accumulators
  • Some Belt Tensioning Thoughts
  • Priorities of an Ideal HVAC System Design
  • 4 Training Tips for your HVAC Company
  • TXV Bulb Placement
  • What does “Saturated State” mean for Techs?
  • 5% vs. 15% Silver Solder (Brazing Rod)
  • Tightening Electrical Threaded Terminal Connections
  • What the Heck is a Friction Rate?
  • Bypass Dehumidification/Airflow HVAC Design
  • Refrigerant Leak Detection and Prevention: Epic Article
  • HVAC Soft Skills Best Practices
  • Static Pressure – Why Measure It?
  • Branding Tips for HVAC Businesses
  • Does An Oversized Furnace Consume More Fuel?
  • Low-Voltage Wiring for Heat Pumps
  • What If Houses Came with Manuals?
  • Grit: A Key Trait in the HVAC Trade (and Life)
  • The Ten Duct Commandments (Plus a Few More)
  • Key Soft Skills for Technicians
  • What Causes Dirty Sock Syndrome?
  • The House is the Biggest Duct
  • Conduction, Convection, and Radiation
  • It’s a Wonderful Life (Compression Refrigeration Edition)
  • Floating Suction and Head Pressure
  • Flame Sensing – The Basics
  • Our Best 3D Animated Videos
  • Transform Impostor Syndrome Into Wisdom
  • Preventing Callbacks and Warranty Returns
  • An Argument for the Trades as a Viable Career Path
  • Residential A/C Install Mindset and Practices
  • Make Networking Work in HVAC/R
  • Conquering the Fear of Failure in a New HVAC Job
  • Leaking (Bypassing) Valves
  • What is the “Mid Point” of a Refrigerant Blend?
  • Take a Deep Breath: Respiratory Hazards in HVAC
  • W1, W2, & E
  • Why Committees are Broken and How to Fix Them
  • Don’t Forget the Service Wrench
  • Commissioning a Residential Split Heat Pump
  • What Techs Need to Know About A2L Refrigerants
  • Flaring Copper: Best Practices
  • Swaging Copper: Best Practices
  • Do You Need to Be Recovering Into a Vacuum?
  • Don’t Use Barometric Pressure For Calibration
  • Remove “Weep” Plugs on Motors
  • What Makes an Autotransformer Different?
  • Let’s Touch On Hand Safety
  • Is It OK To Top Off With R410a?
  • Technician Profitability: Increase Your Value
  • Total External Static Pressure (TESP): A Basic Review
  • Oxygen Safety Tip – No Oil and Grease
  • The Pressures Look Good
  • Think Before You Drill
  • Revisiting the Bull in a China Shop: Oversized Equipment
  • Defrost Termination & Fail-Safe
  • What Causes Voltage Drop and How to Deal With It
  • What is a Thermocouple?
  • Are YOU an Autodidact?
  • Why Selecting Equipment is Important (and Hard)
  • Zonal Pressure Diagnostics—The Backtalk Series (Part 3)
  • Mean Radiant Temperature: What It Is and Why We Should Care
  • What I’ve Learned From Teaching in a Trade School
  • The 3 Fan Laws and Fan Curve Charts
  • An Evaporator Coil With No Fins?
  • Ductless Line Sets and Corrosion
  • Averaging Thermistors and How They Work
  • RH, DB, and WB
  • Historic Homes: Handle with Care
  • Law of Perfect Gas
  • The TXV Powerhead and What it Does
  • Zonal Pressure Diagnostics—The Backtalk Series (Pt. 2)
  • Setting Sights on Safety: Eye/Face Risks and PPE
  • Recovery Tank Safety
  • Dalton’s Law
  • Charles’s Law
  • Why (and When) Do We Need Defrost?
  • Prevent Refrigerant Migration
  • Zonal Pressure Diagnostics—The Backtalk Series (Pt. 1)
  • Boyle’s Law
  • Third Law of Thermodynamics
  • Second Law of Thermodynamics
  • First Law of Thermodynamics
  • Zeroth Law of Thermodynamics
  • Newton’s Laws of Motion
  • Conservation of Energy Law
  • Sweeping with Nitrogen
  • 5 Install Mistakes that Kill Systems
  • Learning from the Past vs. Allowing it to Control You
  • Fan On or Fan Auto
  • What is Inductive Reactance?
  • What’s the Difference Between 208v and 240v?
  • Air Velocity Quick Tips
  • How a Heat Pump Reversing Valve Works
  • Calculate Recovery Tank Fill the Easy Way
  • What is Isentropic Compression?
  • Evaporative Cooling Basics
  • Getting the Most From Value Engineering
  • Mini-Splits for New HVAC Techs
  • Electricity and the Heart
  • Refrigerant Cycles Without Compressors
  • Why Checking Gas Valve Leakage is Hard
  • Impacts of Compression on Temperature
  • Refrigeration Without Refrigerant
  • What is Net Refrigeration Effect (NRE)?
  • How to Send Heat to Outer Space—What Ancients Knew That You Don’t
  • What is Compressor Volumetric Efficiency?
  • Understanding Heat Transfer
  • False Alarms: The Legacy of Phosgene Gas
  • History and Basics of Refrigeration
  • Entropy in Refrigeration and Air Conditioning
  • Saturation and the Pressure-Temperature Relationship
  • Is Liquid Incompressible?
  • How to Clean a Mitsubishi Mini-Split Blower Wheel
  • How to Compare Heat Sources For Cost Effectiveness
  • Getting the Right Part: The Often Overlooked Part Numbers You Should Care About
  • How to Recover Refrigerant Quickly and Properly
  • 5 Money Mistakes to Avoid in Service Business
  • The What and Why of SEER2
  • Drain Cleaning Protocol
  • EER & COP vs. SEER & HSPF
  • Top 10 HVAC Tech Tips
  • Some Furnace Questions
  • Get (and Give) More From Remote Training
  • You Can’t Eat Soup with A Fork……..
  • Multi-Position Service Valves
  • Nomenclature and How to Use It
  • Removing a Blower Motor
  • The Case For Pulling The Blower Housing
  • Dielectric Grease: What It Is and How To Use It
  • Connecting Transformers in Parallel
  • The Hands-On Learner Vs. The Visual Problem Solver
  • Sensors, Measurements, and Physics
  • Tubing and Piping Support
  • Crankcase Heaters and Single-Pole Contactors
  • TD of Refrigeration Evaporators
  • Cycle Rate Settings – A Quick Review
  • What to Check Before Condemning the TXV
  • Hot Pull Down and What it Means
  • Air Flow and Ice – A Thought Experiment
  • Coil SHR, Ventilation, and Bypass Factor – Advanced Psychrometrics Part 2
  • Refrigerants, Flammable & Toxic
  • Room Sensible Heat & CFM – Advanced Psychrometrics Part 1
  • Watts So Confusing?
  • Why HEPA is a Great IAQ Option
  • How to Use a Manufacturer Fan Table and Why They are Important
  • 7 Horribly Challenging Ways To Transform Your Business
  • Locating a Low Voltage Short in Residential A/C Systems
  • Blowers, Props, and How They Behave (or Misbehave)
  • Relative Humidity in the Supply Air Stream
  • Refrigeration Pump-down Cycle
  • Skills in the Toolbag
  • How to Keep From Getting Bored at Work
  • Wiring and Setting of Humidistat/Dehumidistat in Humid Climates
  • A Future We Can All Hope For
  • 6 Ways to Make a Tough Decision
  • Trap and Vent – A Drain Debacle
  • Underlying Problems That Get Missed
  • The Surefire Way to Get a Blower Wheel Off
  • Sometimes, Experience Can Hold You Back
  • Ventilation, Filtration, and Humidity Control: The Holy Trinity of IAQ
  • Oxidizers and What It Has to Do With COVID-19
  • Refrigeration Gas Defrost
  • Do You REALLY Want Feedback?
  • How I Failed to Re-diagnose: The Lesson I Learned
  • 4 Ways to Tell if You are becoming “That Boss”
  • Oxyacetylene Torches: Tips and Operation
  • Introverts Can Sell
  • Compressors and Pumps
  • Liquid Line Solenoid Valves: Long Line Applications
  • The Ductless Dehumidification Conundrum
  • Trades and the Skills Gap – A Manifesto
  • Using Power Factor to Check Capacitors Under Load
  • Checking the Charge on a Heat Pump in the Winter
  • The Learning Mindset – Trial & Error
  • The Learning Mindset – It Isn’t Obvious Until It Is
  • Balanced Port TXV
  • The HVAC/R Diagnosis Pyramid of Skill
  • Milivolt Systems w/ Modern Thermostats
  • A Christmas Meltdown
  • Ball Bearing vs. Sleeve Bearing Motors
  • An Electric Heat Mistake
  • Try and Stay Warm
  • Clocking a Gas Meter (It’s not that hard)
  • Recovery Tank Capacity
  • Don’t Forget the Panel
  • How to Use the Progress Ratchet
  • The Slow Death of the Honest Technician
  • Know the Limits of Subcooling
  • Modulation Motors
  • Tech Question – Why Do ECM Motors Trip a GFCI?
  • Heat Pump Defrost Sensor vs. Thermostat
  • Don’t Install Your Micron Gauge at the Pump
  • Aftermarket Motor Selection & Considerations
  • Testing a Thermocouple
  • AHR NATE Class + Test
  • HP, Motor HP, BHP, Motor Watts
  • ACFM, SCFM, & Baseball dents
  • Ain’t No Fooling With Free Cooling (Tales of the Economizer)
  • Like a Bull in a China Shop – An Oversizing Story
  • The 10 Commandments of the HVAC/R Technician
  • Accumulator & Burnout Considerations
  • Some Range Hood IAQ Thoughts
  • The Good Old Heat Anticipator
  • Open and Closed Case
  • Can Pulling a Vacuum too Fast Freeze Water/Moisture?
  • Non-Bleed TXV & Trapped Nitrogen
  • Four Ps of IAQ
  • Dalton’s Law of Partial Pressures
  • 3-Wire and 4-Wire Condensing Fan Motor Connection
  • Fan (Blower) Efficacy
  • What Willis Understood 
  • What is “Cascade” Refrigeration?
  • The Two OTHER EPA violations
  • Cleaning Condenser Coils Still Matters
  • Sealing Boxes/Boots/Cans
  • Motor Service Factor
  • Subcooling vs. Liquid Line Temperature
  • The “5 Pillars” of Residential A/C Refrigerant Circuit Diagnosis
  • Testing Electric Heat – A Cautionary Tale
  • Introduction to VAV Systems
  • Bending EMT
  • What is an ERV?
  • Getting Involved In HVAC/R Education
  • Famous Last Words (Before a Callback)
  • How “Hot” Does That Get?
  • What Is Temperature Glide?
  • Why the 20° Rule is Driving The Internet Crazy
  • Multi Tap Primary Transformers
  • Strip Control Wires Properly
  • Subcool and Liquid Line Length
  • Compressor Performance Analysis
  • Leak Detector Maintenance and Care
  • Hot Weather Preparedness/An Open Letter (Surviving a Heat Wave)
  • Sensible Heat Ratio (SHR)
  • Defrost Time & Temperature
  • Motor Types
  • Micron Gauges Gone Wild
  • Cased Coil Misalignment
  • CO2 Booster Systems (Codenamed CO2 is Interesting and Weird)
  • A job well done….. Almost
  • Changing Liquid Filter/Drier Cores Tip
  • Adjustable Drive Pulley (Sheaves)
  • Grounding and Bonding Myths
  • 20° ΔT (Delta T), A Lazy Rule of Thumb
  • Solenoid Facts
  • 500 BTUs per Person Per Hour?
  • Capacitors – Series and Parallel
  • Walk-In Cooler Defrost
  • Storming the Gates to Trade Education
  • Humidifier Facts
  • Checking the Charge Without Gauges (Our Process)
  • Condensate Drainage in a High Efficiency Gas Furnace
  • Duct Smoke Detectors/Alarms and the Code
  • VRV Operation
  • Remote Ice Machines – The Basics
  • But My Old Unit Worked Fine?!
  • Comparing Manual J to Reality
  • VRV/VRF Installation Tips
  • VRV Basics
  • Ever Hear of Copper Plating Inside the Compressor?
  • What is a Suction Accumulator?
  • Properly Diagnosing a Gas Furnace Pressure Switch
  • A Steam Heating Primer
  • Choosing the Right Vacuum Pump Oil
  • Commercial Refrigeration Compressor Operation
  • The Why Behind the Lies
  • Market Refrigeration TXV Adjustment
  • Ice Machine and Scale (Limescale)
  • 3 Things I Would Do Differently in Business
  • TH, TR, and TH/TR Gas Valve Terminals
  • Salamander Broiler Cleaning
  • Thermal Expansion & Dissimilar Metals
  • Dehumidifier Facts & Troubleshooting
  • Vacuum Pump Oil
  • Triple Evacuation and Nitrogen FACTS
  • Does a Furnace Decrease Humidity?
  • Relative Humidity of Air Below Freezing
  • Pressure / Enthalpy Diagram Example
  • Electronic Leak Detection DOES WORK
  • Start Capacitor & Inrush, Facts & Myths – Part #4
  • Start Capacitor and Inrush Facts & Myths – Part #3
  • Start Capacitor and Inrush Facts & Myths – Part #2
  • Start Capacitor & Inrush Facts and Myths – Part #1
  • Commercial Contactor Considerations
  • Design Temperature Difference for Chillers 
  • Oil Management and Diagnosis
  • Simple Pump Selection Part 2
  • Simple Pump Selection Exercise
  • How to Determine the Friction Rate for Residential Duct Design
  • Pressure Difference and Pump Flow
  • Some Important Terms to Know
  • Two Less Common TXV Issues to Watch For
  • Thoughtful Termination (Of Wires)
  • Introduction to Pool Heat Pumps
  • No, Recharging R22 Isn’t “Illegal” in the US
  • An Old Timer’s Trick to Get Unstuck
  • Multimeter Categories
  • Removing Water From a Float Switch
  • Basic Refrigeration Startup & Commissioning
  • Conditioned Makeup Air
  • A Critical Technician Trait in Decline
  • The “Other” Pressure Switch
  • Careful With That 40VA Transformer
  • Workers of The World UNITE!
  • Oil Pressure Controls
  • Lifting Techniques Part 4 – Using Unistrut
  • Lifting Techniques Part 3 – Complex Block & Tackle
  • Lifting Techniques Part 2 – Pulleys
  • I Really Want to Learn More!
  • Lifting Techniques Part 1 – Basics
  • What is a DIN Rail?
  • Use Your Senses First
  • TXV Power Element of Surprise
  • Fire Damper Tips
  • Can A Motor Run Backwards by Swapping Run & Start?
  • The Dangers of the “Diesel Effect” (Compressor Explosion)
  • Troubleshooting for HVAC/R – Repairs, Reevaluation and Wrap up
  • Troubleshooting for HVAC/R – Data Analysis
  • Troubleshooting For HVAC/R – Gathering Data 
  • Troubleshooting For HVAC/R – The Don’t List
  • The Troubleshooting Mindset
  • Testing the Leak Rate on Your Micron Gauge Itself
  • Ideas Have Consequences
  • Incorporating Electrical Quality Into Diagnosis
  • Can You Discharge a Capacitor Using a Voltmeter?
  • Refrigeration Equipment Diagnosis Method
  • Powered Attic Ventilation
  • Drip Loops and Straws
  • Keys to Success – Find a Mentor
  • How Long Should I Evacuate a System?
  • Hyperion Troubleshooting
  • Tunnel Vision and How to Avoid It
  • Stacking Evaporator Coil Stages
  • Equipment Grounding
  • Duct Leakage Can Be Costly
  • Ideal Gas Rulebreakers
  • Get an EEV Open (Like Magic)
  • What Does “Air Free CO” (Carbon Monoxide) Mean?
  • Density of Air & Water Part 2
  • You’re Grounded
  • High Capacity Amperage Measurement
  • Pool Heat Pumps, The Basics
  • Troubleshooting Advanced Systems
  • Sensible Heat in Air and Water
  • Diffuser Placement is Important
  • Determining the Air-Side Charge of an Expansion Tank
  • Calculating Target Delta T w/ Manufacturers’ Data
  • Hydronics GPM Calculation and More…
  • HVAC Fire Safety Systems in Restaurants
  • Air is Squishy – Measuring Airflow w/ Bill Spohn
  • Reach-In Temperature Controls
  • Condensate Pump Drains
  • A Simple Piping Practice
  • Ohm My
  • Watch It, Hercules 
  • The Case for Checking the Charge Without Using Gauges
  • Does Nitrogen Pressure Change with Temperature – Practical Application of Gas Laws
  • What 2018 Holds for Techs
  • EcoBee Thermostats and Dehumidification
  • Replacing a Piston w/ TXV and Evacuation
  • Be Careful When Jumping Out a Blower
  • Ice Machines – Cuber, Flaker & Nugget Basics
  • Static Pressure and Combustion Test Ports and Plugs
  • Boiler Basics Part 2 – Components
  • Boiler Basics Part 1 – Types and Components
  • Giving Static for Failing to Take Static 
  • Other Great Sources
  • A Case For Wireless Refrigerant Probes
  • MeasureQuick Launch Is HERE
  • Change O-rings, Not Hoses
  • What if you Only Have One Large Hose?
  • Don’t use Tank Caps on Systems
  • EPR valves 101
  • Purge Your Hoses
  • Building Automation Basics for the HVAC Tech w/ Phil Zito (Podcast)
  • Splicing Wires – Bad, Good, Better, Best
  • False Negatives on One Capacitor Test
  • An even EASIER way to check capacitors
  • UV Lights
  • Testing Run Capacitors the Smart (and Easy) Way
  • Why You Need a Torque Wrench (or Two…)
  • R22 Retrofit Tips
  • Leak Detection on Large Systems
  • No, It’s NOT a Ground!
  • Boiler Basics Part 4 – Piping
  • Oil Nozzles
  • Venting for High-Efficiency Gas Furnaces – Part 2 Assembly
  • Venting for High efficiency Gas Furnaces – Part 1 Materials
  • Boiler Basics Part 3 – Steam
  • Lifting Techniques Part 5 – Really HEAVY Stuff
  • Something You May Want to Consider on Every Call
  • Oil and Refrigerant
  • Are The Multi-Taps on a Blower Run or Common?

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