Tech Tips
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- 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
- Giving Thanks for the Hard Stuff
- Old Books
- Why is 240V called “Single-Phase”?
- Leaking (Bypassing) Valves
- What is the “Mid Point” of a Refrigerant Blend?
- Maintenance During Major Repairs
- 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
- That Rusty Coil/Galvanic Corrosion
- 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?
- Compressor Mass Flow – Some Thought Experiments
- Let’s Touch On Hand Safety
- Does a Motor Draw More or Less at lower Voltage?
- 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
- Proper Liquid Line Drier Location
- Revisiting the Bull in a China Shop: Oversized Equipment
- Motor Overheating
- Defrost Termination & Fail-Safe
- Careful With Cleaners
- Don’t Squeeze a Radiant Barrier
- 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)
- Gluing Tubing Insulation
- 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
- Don’t Fall for Unsafe Practices: Heights in HVAC
- Charles’s Law
- Why (and When) Do We Need Defrost?
- Lockout/Tagout Basics
- 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 to Replace a Condensing Fan Motor
- 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
- Storing Food for Flavor and Safety
- Mini-Splits for New HVAC Techs
- Electricity and the Heart
- Refrigerant Cycles Without Compressors
- Why Checking Gas Valve Leakage is Hard
- 3 Bad Techs Who Don’t Know It
- 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?
- The Misunderstood Lockout Relay
- Understanding Heat Transfer
- False Alarms: The Legacy of Phosgene Gas
- History and Basics of Refrigeration
- Entropy in Refrigeration and Air Conditioning
- Do You Replace the Contactor and Capacitor With a New Compressor
- 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
- 3-Phase Motors—The Basics
- 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
- Understand Heat Pumps
- Removing a Blower Motor
- The Case For Pulling The Blower Housing
- Piston Design and Bypass
- Does the Voltage or the Amperage Kill You?
- Indirect Soldering Technique
- Dielectric Grease: What It Is and How To Use It
- Connecting Transformers in Parallel
- Checking Evaporators on Furnaces
- The Hands-On Learner Vs. The Visual Problem Solver
- Does Air or Nitrogen Absorb Water?
- What Should My Superheat Be?
- Sensors, Measurements, and Physics
- Tubing and Piping Support
- Crankcase Heaters and Single-Pole Contactors
- Capacitor Testing and Replacement Procedure
- TD of Refrigeration Evaporators
- Shielded Control Cable & Communicating Controls
- Cycle Rate Settings – A Quick Review
- Fan Blade Shroud Depth
- What to Check Before Condemning the TXV
- Size and Orientation of Return Grilles and Supply Registers
- Does Setpoint Lead to Freezing?
- Checking Disconnects
- Why is 3/8″ Liquid Line So Common? Liquid Line Sizing
- Is a Smaller Suction Line OK? – Suction Line Sizing
- Why Compression Ratio Matters
- Flex Ducts – Best Practices
- Attic Equipment Codes
- Short Circuits
- Hot Pull Down and What it Means
- Air Flow and Ice – A Thought Experiment
- Refrigerant Charging Basics For Air Conditioning & Heat Pump Systems
- Coil SHR, Ventilation, and Bypass Factor – Advanced Psychrometrics Part 2
- Refrigerants, Flammable & Toxic
- Room Sensible Heat & CFM – Advanced Psychrometrics Part 1
- Watts So Confusing?
- Avoiding and Eliminating Callbacks
- Why HEPA is a Great IAQ Option
- C stands for “Common Mistake”
- 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
- 5 Things to Consider When Maintaining a Commercial Package Unit
- 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
- What Should My Subcooling Be?
- Wiring and Setting of Humidistat/Dehumidistat in Humid Climates
- A Future We Can All Hope For
- HVAC Contractors Guide to COVID-19 (SARS-CoV-2, Coronavirus)
- 6 Ways to Make a Tough Decision
- Trap and Vent – A Drain Debacle
- Why A/C Systems Freeze
- 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
- Wet Bulb and Enthalpy – The Left Side of the Chart
- Oxidizers and What It Has to Do With COVID-19
- Refrigeration Gas Defrost
- Techs are Under Pressure
- 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
- Wide, Narrow, Wide Diagnosis
- Air Filter Static Pressure Drop
- A Tale of Two Latents
- Flash Gas
- The Ductless Dehumidification Conundrum
- Trades and the Skills Gap – A Manifesto
- Using Power Factor to Check Capacitors Under Load
- 5% vs. 15% Silver Solder (Brazing Rod)
- 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
- Using Heat & Nitrogen In Vacuum
- Why Measuring Static First Isn’t Always Productive
- It Has a Flat For a Reason
- 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
- How (and Why) to Flow Nitrogen While Brazing
- Furnace Air Temperature Rise
- Clocking a Gas Meter (It’s not that hard)
- Recovery Tank Capacity
- Flame Sensing – The Basics
- 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?
- Electric Heat & Blower Interlock
- Combustion Air
- Heat Pump Defrost Sensor vs. Thermostat
- Crankcase Heaters
- What You Know About Start Winding Inrush Might Be Wrong
- Don’t Install Your Micron Gauge at the Pump
- Heat Pump Defrost Boards and W2
- 5 Terror-Inducing HVAC/R Stories & Facts
- 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)
- Static Pressure, Manometers, and Magnehelics
- Like a Bull in a China Shop – An Oversizing Story
- Three-Phase Voltage Imbalance
- What is a HSO (non-bleed) TXV/TEV?
- The 10 Commandments of the HVAC/R Technician
- Accumulator & Burnout Considerations
- ECM, VFD, and Inverter – What’s the Difference?
- Some Range Hood IAQ Thoughts
- A Common Sense Look at Temperature Conversions
- Pitch on Line Penetrations
- The Good Old Heat Anticipator
- Some Belt Tensioning Thoughts
- A Liquid Line Solenoid and What it Does
- Open and Closed Case
- Can Pulling a Vacuum too Fast Freeze Water/Moisture?
- Isolation Diagnosis
- 5 Simple Service Valve Tips
- Non-Bleed TXV & Trapped Nitrogen
- TXV Bulb Placement
- Four Ps of IAQ
- Dalton’s Law of Partial Pressures
- How Moisture Moves
- Beware of “Ghost” Voltage
- 3-Wire and 4-Wire Condensing Fan Motor Connection
- Fan (Blower) Efficacy
- What Willis Understood
- What is “Cascade” Refrigeration?
- Impacts of Decreasing Evaporator Airflow
- Double Lugging, A Common Mistake
- The Ten Duct Commandments (Plus a Few More)
- The Two OTHER EPA violations
- Cleaning Condenser Coils Still Matters
- What is the Difference Between ACH & ACH50?
- Sealing Boxes/Boots/Cans
- 5 Capacitor Facts You Should Know
- Motor Service Factor
- Subcooling vs. Liquid Line Temperature
- The Unexpected Result of Series Circuits
- The “5 Pillars” of Residential A/C Refrigerant Circuit Diagnosis
- Don’t Get Depressed (Unless You’re a Core)
- This is Not a Soft Start
- Testing Electric Heat – A Cautionary Tale
- Introduction to VAV Systems
- Work Vehicle Entropy
- How much PRESSURE is that Recovery Tank Designed For?
- Bending EMT
- What is an ERV?
- Air Changes Confusion
- Getting Involved In HVAC/R Education
- Famous Last Words (Before a Callback)
- How “Hot” Does That Get?
- Inches of Water Column
- The “Approach” Method of Charging and Condenser Efficiency
- How to Diagnose a TXV Failure
- Uncommon Start and Run
- Hit Your Spots
- Why Discharge Line Temperature is a Useful Reading
- Infrared Thermometers Can Cause Confusion
- 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
- The Diagnosis Game (and Why Van Sleeping Bothers Me)
- Leak Detector Maintenance and Care
- Hot Weather Preparedness/An Open Letter (Surviving a Heat Wave)
- Short-Cycling
- Sensible Heat Ratio (SHR)
- Defrost Time & Temperature
- Motor Types
- Switch Terms
- Micron Gauges Gone Wild
- Charging Systems with Accumulators
- What does “Saturated State” mean for Techs?
- How to Reduce Indoor Humidity
- Weighing Refrigerant In and Out
- Cased Coil Misalignment
- The Impact of Adding or Removing Water From Air
- Unapologetically a Technician
- CO2 Booster Systems (Codenamed CO2 is Interesting and Weird)
- A job well done….. Almost
- Properly Deburring (Reaming)
- 32° Saturation (Evap Temperature)
- Changing Liquid Filter/Drier Cores Tip
- Adjustable Drive Pulley (Sheaves)
- Is it too cold to set the charge?
- Something to Watch For When Replacing a Thermostat
- Grounding and Bonding Myths
- 20° ΔT (Delta T), A Lazy Rule of Thumb
- Refrigerant Oil Basics
- Adiabatic Cooling, Blower Settings, and Why You Care
- Solenoid Facts
- 500 BTUs per Person Per Hour?
- Capacitors – Series and Parallel
- Potential for Good and Evil (The Hard Start & Potential Relay)
- Condensate Drain Codes & Best Practices
- Walk-In Cooler Defrost
- Why is the Breaker Tripping?
- Non-noncondensables
- Storming the Gates to Trade Education
- Humidifier Facts
- The Difference Between Variable Speed and X13 Motors
- Checking the Charge Without Gauges (Our Process)
- Glide at Static Pressure
- Condensate Drainage in a High Efficiency Gas Furnace
- Duct Smoke Detectors/Alarms and the Code
- HVAC/R Refrigerant Cycle Basics
- VRV Operation
- Remote Ice Machines – The Basics
- But My Old Unit Worked Fine?!
- Refrigerant Basics
- Comparing Manual J to Reality
- Why Many Techs Confuse Overload, Short, & Ground Fault
- VRV/VRF Installation Tips
- Laws of Energy and Matter
- Gas Law Concepts for HVAC/R
- Infrared vs. Heated Diode Leak Detectors
- VRV Basics
- Ever Hear of Copper Plating Inside the Compressor?
- Introduction to SORIT Valves
- What is a Suction Accumulator?
- Properly Diagnosing a Gas Furnace Pressure Switch
- A Steam Heating Primer
- What are Dry and Wet Contacts?
- Choosing the Right Vacuum Pump Oil
- Commercial Refrigeration Compressor Operation
- 4-20ma Control Basics
- The Why Behind the Lies
- How to Set a Charge by Superheat
- Market Refrigeration TXV Adjustment
- Understanding Relays With the 90-340
- Low Airflow – Beyond the Obvious
- Ice Machine and Scale (Limescale)
- Scroll Compressor Pump Down, Megohm Test & Fusite Terminals
- Diagnosing and Finding a Refrigerant Restriction
- Air Barrier vs. Vapor Barrier vs. Insulation
- Finishing Trade School? Some Things you Need to Know
- 3 Things I Would Do Differently in Business
- TH, TR, and TH/TR Gas Valve Terminals
- Salamander Broiler Cleaning
- Thermal Expansion & Dissimilar Metals
- The Sneaky Effects of Radiant Heat Transfer
- Dehumidifier Facts & Troubleshooting
- Heat Doesn’t Rise
- Vacuum Pump Oil
- Triple Evacuation and Nitrogen FACTS
- Pool Heater Water Flow Issues
- Does a Furnace Decrease Humidity?
- Relative Humidity of Air Below Freezing
- What is Fenestration and Why Do I Care?
- Pressure / Enthalpy Diagram Example
- Diagnosing ECM & X13 Motors
- The Friction Rate Chart (and What it Means)
- Electronic Leak Detection DOES WORK
- Heat Exchanger Crack Diagnosis
- What is Flux?
- Condensate Switch Controversy
- Negative Superheat? Time to Check Your Tools
- THE MOST IMPORTANT Skill a Tech Can Have
- 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
- Pre-Cleaning Copper
- Oil Management and Diagnosis
- Simple Pump Selection Part 2
- What does “RES” mean on a contactor or relay?
- What’s So Wrong With “Beer Can Cold”?
- Simple Pump Selection Exercise
- How to Determine the Friction Rate for Residential Duct Design
- Pressure Difference and Pump Flow
- HVAC/R Brazing Indicators
- What Causes Dirty Sock Syndrome?
- Some Important Terms to Know
- Does Refrigerant Get Old or Wear Out?
- Testing, Recovery, and Charging a Sealed System
- Common Concrete Anchor Fails
- Technician Head Trash
- 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
- The Basic Residential Maintenance for a Heat Pump / Electric Systems
- Multimeter Categories
- Removing Water From a Float Switch
- Basic Refrigeration Startup & Commissioning
- Conditioned Makeup Air
- Why and how to adjust a TXV/TEV
- Parallel Circuit Resistance
- A Critical Technician Trait in Decline
- The “Other” Pressure Switch
- Careful With That 40VA Transformer
- The Secrets to Happy HVAC Customers
- Workers of The World UNITE!
- Oil Pressure Controls
- Condenser Coil Cleaning Step by Step
- 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?
- 8 Tips for New Techs (So You Don’t Get Fired)
- What is Enthalpy?
- Use Your Senses First
- TXV Power Element of Surprise
- Sight Glass/ Moisture Indicator
- Fire Damper Tips
- What is a Micron?
- Can A Motor Run Backwards by Swapping Run & Start?
- Control Voltage Overamp – The Less Usual Cause
- 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
- Mistakes in Measuring Ohms
- Testing the Leak Rate on Your Micron Gauge Itself
- Cooling Capacity Isn’t Always What it Seems
- Ideas Have Consequences
- Incorporating Electrical Quality Into Diagnosis
- Can You Discharge a Capacitor Using a Voltmeter?
- Motor Speed – The Basics
- Refrigeration Equipment Diagnosis Method
- Powered Attic Ventilation
- Drip Loops and Straws
- How to Make Better Decisions
- What is a GFI?
- Axial, Radial, and Digital Scrolls
- Keys to Success – Find a Mentor
- Bernoulli’s Principle
- How Long Should I Evacuate a System?
- Hyperion Troubleshooting
- Exposed Duct High Temperature Limit
- Making a Flare – Quick Tips
- Tunnel Vision and How to Avoid It
- Understand Dew Point and Absolute Moisture, The Right Side of the Psych Chart
- Stacking Evaporator Coil Stages
- A REALLY loud compressor
- Equipment Grounding
- What ‘s the scoop on PM10 and PM2.5 Particles?
- 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
- Better Temperature Measurements
- Troubleshooting Advanced Systems
- Sensible Heat in Air and Water
- Diffuser Placement is Important
- 4 Silly Mistakes of The New HVAC Tech
- Determining the Air-Side Charge of an Expansion Tank
- Calculating Target Delta T w/ Manufacturers’ Data
- Hydronics GPM Calculation and More…
- Receiver Basics
- HVAC Fire Safety Systems in Restaurants
- Air is Squishy – Measuring Airflow w/ Bill Spohn
- Start Flowing Nitrogen Sooner
- Reach-In Temperature Controls
- What You Need to Know About MicroChannel
- Condensate Pump Drains
- A Simple Piping Practice
- Fancy Refrigerant Words
- Ohm My
- Are You a “Tom Brady” Tech?
- Watch It, Hercules
- Switch voltage
- Piston vs. TXV Metering Devices
- The Case for Checking the Charge Without Using Gauges
- Does Nitrogen Pressure Change with Temperature – Practical Application of Gas Laws
- The Extension Cord Puzzle
- What 2018 Holds for Techs
- EcoBee Thermostats and Dehumidification
- Combustion and Confined Spaces
- It’s a Wonderful Life (Compression Refrigeration Edition)
- Replacing a Piston w/ TXV and Evacuation
- Be Careful When Jumping Out a Blower
- Ice Machines – Cuber, Flaker & Nugget Basics
- How to use an Adjustable (Crescent) Wrench, Pipe Wrench and Tongue & Groove (Channel Locks) Wrenches
- 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
- Changing Refrigerants and Why it Matters to You
- Other Great Sources
- Drains and Double traps
- A Case For Wireless Refrigerant Probes
- Which Valve Do I Open First?
- MeasureQuick Launch Is HERE
- Change O-rings, Not Hoses
- What if you Only Have One Large Hose?
- Pull The Top
- Don’t Forget the Suction Filter/Drier
- Static Pressure – Why Measure It?
- Don’t use Tank Caps on Systems
- EPR valves 101
- Condensation – It Isn’t Where Hot Meets Cold
- Purge Your Hoses
- Building Automation Basics for the HVAC Tech w/ Phil Zito (Podcast)
- Setting & Checking a Charge in the Rain
- Refrigerant Recovery Practices
- 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
- Ohms/Continuity Basics
- 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
- Electronic Leak Detection
- Something You May Want to Consider on Every Call
- Oil and Refrigerant
- Are The Multi-Taps on a Blower Run or Common?
