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Articles
The HVAC Interview: Preparing and Dressing for Success
Landing a job in HVAC is unique because every employer has a different philosophy on professionalism. For some, the goal isn't just to look good—it...
Classroom Projects
How to Read a Tape Measure in Inches and Fractions!
When teaching students how to use and read a tape measure for the first time, I have a go-to set of items to facilitate the training. I use 13 piec...
Quick Tips
Make Sure to Connect You Gauge Quickly To Prevent Contamination!
If you remove the vapor access port cap on a running air conditioning system, the low temperature brass on the inside of the port will condense wat...
Quick Tips
Do You Need Locking Caps On Refrigerant Access Ports!
After servicing or adding refrigerant to an air conditioning system, add locking caps to the service ports if the system is in an accessible area. ...
Quick Tips
Quickly Check For Condensate Clogs and Issues During no A/C Service Calls!
There are a number of factors that lead to a residential NO A/C service call, so make sure to rule out the condensate line/switches! These switches...
Classroom Projects
Seeing the TXV Metering Device Operate Using A Water Stream!
The purpose of this HVACR training project is to visually show your students the change in the amount of liquid flowing through a TXV or Piston Met...
Articles
5 Methods to Determine if The Indoor Air Conditioning Coil is Clogged with Dust!
When servicing an air conditioner or heat pump, we often notice a low airflow problem which needs to be fixed. If there is no indoor air filter or ...
Articles
Measuring the Static Pressure Drop Across an Evaporator Coil to See if it is Clogged!
If you suspect that an evaporator coil is clogged with dust but cannot visually see it, such as when you can't directly inspect on a furnace and ev...
Articles
Measuring Airflow in CFM Using the TrueFlow Grid
Measuring airflow is one of the most commonly missed or ignored topics in HVAC when commissioning or diagnosing problems in systems. I don't believ...
Articles
Carbon Monoxide Alarm vs Low Level CO Monitor
Today most people are aware of the invisible, odorless, poisonous gas of Carbon Monoxide or CO for short. Now we know that even low levels of CO ca...
Articles
Top 10 Gas Furnace Package Unit Problems!
Problem #1 : No Power to the Package Unit On all HVAC systems, power is critical to operation, and a package unit is no different. There several re...
Quick Tips
UNCONFORMED Review (Quick Tip)
I just finished reading the book Unconformed, by Bryan Orr, from HVAC School. I invested about 5 hours spread over three days and let me tell you, ...
Articles
ECM Fan Motor Troubleshooting for Constant Torque Motors: X-13 and Broad Ocean
ECM “constant torque” fan motors can be easily identified by noticing their spade terminal plug ends. However, make sure to read the motor's rating...
Quick Tips
The Directional Flow of Refrigerant in a Heat Pump During AC Mode (Quick Tip)
(This image is courtesy of our friend JD Kelly @student_of_hvac ) In this refrigerant flow diagram, we see a simplistic piping arrangement for a he...
Quick Tips
Simple Low Voltage Thermostat Wiring to Control an Indoor Blower Motor (Quick Tip)
(This image is courtesy of our friend JD Kelly @student_of_hvac ) This drawing shows how a low voltage wiring circuit can control a high voltage, h...
Classroom Projects
HVAC Training For Thermostat Operation, Wiring, & Multimeter Use!
This short project is designed to show how to teach thermostat operation and wiring to a newer HVAC technician or a student in a mobile and easy to...
Articles
10 Methods to Clean Condensate Drains/Traps on Air Conditioners
In this article, we go over 10 methods to clean out condensate drain lines and traps on air conditioning systems! The condensate drain line is resp...
Classroom Projects
EEV Electric Expansion Valve Training Project
Explaining how an EEV operates is much easier when you can show exactly what is happening, each step of the way. This project is meant to simplify ...
Classroom Projects
Pressure Transducer Training Project
This training project is designed to provide a clear way to see how a pressure transducer operates and how they can be tested. Why does the Pressur...
Classroom Projects
HVAC Thermistor Training Project
This training project is designed to show how bead thermistors and tube thermistors work, along with the difference in sensitivity between the two....
Classroom Projects
Mini Split LOUVER MOTOR Training Project
Explaining how a louver motor operates is much easier when you can watch the louver blade move, each step of the way. This project is meant to simp...
Articles
Where To Find R-22 & R-410A Leaks on AC Units! Top 10 Spots!
This article covers the ten most common locations where refrigerant leaks may be on an air conditioning system. An electronic leak detector is typi...
Articles
Top Ten Interview Tips to Land that HVAC/R Job!
It is certainly important to have good training and/or experience in the field prior to applying for an HVAC/R position. However, some do not have ...
Articles
10 Reasons a Blower Fan Won't Start in a Furnace, AC or Heat Pump
This article covers the 10 most common reasons the blower fan does not turn on! A blower motor may be installed in a forced air gas or oil furnace,...
Articles
Suction Line Accumulator Tank Function, Location, & Purpose
In this article, we discuss the accumulator tank, its function, why its used, and its location in the system. The photo below shows the inside of a...
Articles
Copper Tube Swaging and Deburring Tools!
Swaging tools are used to expand the end of a copper tube to accept the next section of tubing. This is done prior to making a permanent braze or s...
Articles
Why a Start Capacitor Fails and Testing!
The Purpose of a Start Capacitor A start capacitor can be found in the electrical compartment of most single speed heat pumps and some outdoor air ...
Articles
Tips For New HVACR Instructors with Ty and Craig!
Basic Characteristics of a Good Instructor "The hardest year of teaching is the one you are currently in." - Ty Branaman Based on their experience,...
Articles
Finding an Airflow Problem using Static Pressure Measurements!
If a furnace or air conditioning system develops an airflow problem, there are several items to visually inspect. If visual inspection does not loc...
Articles
ATTIC FANS! Troubleshooting Common Problems!
An attic fan is used to lower the temperature within the building shell between the roof structure and the living space. The fan's job is to pull o...
Articles
Copper Tube Bending Tools and Methods
There are four methods for bending soft copper tubing. Copper tubing can be bent to the correct measurement using a lever type bending tool, a ratc...
Articles
Pressure Testing Gas Lines for Leaks! Natural Gas and Propane (LP)
Fuel gases such as Propane or Natural Gas are a regular part of everyday life for many. Whether it is used to heat a home, cook a meal, or to warm ...
Articles
6 Reasons Why a Furnace Blower Fan Motor Won’t Shut Off!
On a natural gas or propane furnace, there are typically 6 main reasons why a blower fan motor may not shut off and just continues to run. Before t...
Articles
Fridge or Freezer Compressor Not Starting? Test Start Relay, Overload, Capacitor, PTC Thermistor
This article explains how to troubleshoot a refrigerator or freezer compressor that does not start. There are different components that can be test...
Articles
Testing if an HVACR Compressor is Shorted to Ground, Open, or the Thermal Overload is Tripped!
In this HVAC Training Article, I discuss how to perform electrical troubleshooting on an HVAC/R compressor to determine if it is bad. Too many time...
Articles
Troubleshooting a Cad Cell Flame Detector for an Oil Burner!
A Cad (Cadmium Sulfide) Cell is a photo conductive flame detector that changes its electrical resistance depending on how much light is available a...
Articles
TOP 5 HVAC CONTACTOR Troubleshooting Problems!
This article explains the "Top 5 Problems" that can occur on a contactor and how to troubleshoot them! The HVAC Contactor is a device that turns on...
Articles
Don't Get Locked Out! Locking Port Cap Quick Tip!
Just because your company only uses one type of port cap doesn’t mean you won’t be called to service a system with another manufacturer’s locking p...
Articles
When Installing or Replacing an Air Conditioner, Use These Procedures for the Refrigerant Tubing!
When installing a new HVAC system, replacing an existing HVAC system, or only replacing one part of the system, there is a sequence of procedures t...
Classroom Projects
HVAC Electrical Training Board For Wiring, Components, Wiring Diagrams, Troubleshooting
Downloadable Wiring Diagrams and the measurement layout are available at the bottom of this page. Instructors are always looking for a low cost, ha...
Articles
TXV Bulb Mounting Position and External Equalization!
The question we are looking to answer is, should we install the TXV bulb before (upstream) or after (downstream of) the external equalization port?...
Articles
Adjusting the Airflow Speed on ECM Blower Fan Motors! (Variable & Multi-Speed Types)
In this HVAC training article, we will be discussing how to adjust the fan speeds on an indoor ECM variable speed blower motor and an ECM constant ...
Articles
Adjusting the Furnace/AC Airflow Speed on a 120v PSC Blower Motor!
In this HVAC training article, we will be discussing how to adjust the fan speeds on an indoor PSC blower motor in furnace and air conditioning uni...
Articles
Top 10 Gas Water Heater Pilot Light Problems! When It Won’t Stay Lit!
This article explains how the thermocouple, gas valve solenoid, and pilot flame work on a water heater. I will be discussing 10 problems that may o...
Articles
How to Find Common, Start, and Run on a PSC Compressor Motor!
In this HVACR Training article, we are using electrical resistance measurements on the PSC compressor terminals in order to determine which tab is ...
Articles
Gas Furnace Electrical Safety Switch Testing!
In this article, we will be discussing methods to test the safety switches in a gas furnace using a multimeter. These switches include the flame ro...
Articles
20 Causes of Low Indoor Airflow on Ducted HVAC Units!
In this HVAC training article, I discuss 20 AIRFLOW Problems that you may find on ducted gas furnaces, air conditioners, heat pumps, air handlers, ...
Articles
Finding a Low Voltage Short Quickly, Step by Step!
In the world of HVAC, low voltage shorts are a common occurrence on a service call. Low voltage shorts occur when an electrical circuit finds a sho...
Articles
The Benefits of Using an Ultrasonic Leak Detector to Find Refrigerant Leaks!
A refrigerant leak may be easy to find when the leak is a large one but when the leak is small, finding it can be tedious and time consuming unless...
Articles
Ductless Mini-Split Step-by-Step Installation
In this step-by-step installation, we will be covering the full installation of a ductless Mini-Split heat pump system. This system happens to be a...
Articles
What Components are in a Forced Air Gas Furnace? What do they Do?
In order to troubleshoot a gas furnace, the technician must have a thorough knowledge of each component that could be in the unit. Understanding ho...
Articles
Troubleshooting an HVAC Control Board? How?
Diagnosing if a control board is bad on a furnace, air conditioner, or heat pump may seem difficult but here are some simple tips and processes to ...
Articles
Clogged Liquid Line Filter Drier?
How can you tell if you have a clogged liquid line filter drier? If there is a noticeable temperature drop from one side of the filter drier to the...
Articles
Is There an Easy Way to Tell if a Mini-Split Ductless Unit is Low on Refrigerant? (Quick Tip)
Is there an easy way to tell if a mini-split ductless unit is low on refrigerant? Yes, if the Delta T is low and the system continues to run withou...
Quick Tips
Why Do Some Evap Coils Leak While Others Do Not? (Quick Tip)
Why do older coils seem to last a long time but ones that are only 10 or 15 years old leak? Energy transfer efficiency was not as much of a concern...
Articles
40 Vacuum Tips for HVACR Technicians! Avoid Frustration!
I put this list together to make sure that HVACR technicians don’t have to undergo the same frustrations, loss of time, and expenses that I did whe...
Articles
Checking the Charge of Air Conditioners Without Measuring Pressure!
Can you check the charge on a system without checking pressure? Sure, remember that the only reason we check pressure is to convert it to saturated...
Quick Tips
Can I measure a Negative Subcooling When Checking the Charge? (Quick Tip)
The answer is no because the refrigerant rejects heat in the condenser so the pressure and temperature of the refrigerant should lower. The refrige...
Articles
R-22 and R-410A Operating Pressures, Charging, and Recovery Setup!
In this article, we will discuss an HVAC unit’s refrigerant pressure on both the high side and the low-pressure side while the system runs. It is i...
Articles
Charging a System in a Dry Climate? Consider a TXV and Accumulator!
In a dry climate, certain considerations must be taken prior to installing or servicing air conditioning systems. A TXV metering device and an accu...
Articles
How NOT to Check the Refrigerant Charge!
There are many ways that technicians have tried to get around actually checking the charge of air conditioners and heat pumps with superheat and su...
Articles
10 Reasons Why a Mini-Split Ductless Flare May Leak Refrigerant!
On a mini-split ductless system, two copper tubes are needed to transport the refrigerant. These copper tubes are referred to as the line set and t...
Articles
Checking the Charge of a Mini-Split Unit!
A question that I get asked frequently is “Can I check the charge of a mini-split ductless unit with superheat and subcooling the same way I do on ...
Quick Tips
Is a Triple Evacuation Necessary for a Deep Vacuum?
Do you have to do a triple evacuation if you can achieve a deep vacuum by only doing a single evacuation? Remember that the target vacuum of 500 mi...
Quick Tips
Measuring Negative Superheat on an Air Conditioner? (Quick Tips)
Can you Measure Negative Superheat on an air conditioner when checking the charge? The Answer is NO! Time to check your gauges and temp sensors for...
Quick Tips
How to Tell if a TXV Has Lost Part of its Bulb Charge! (Quick Tip)
How do you tell if a TXV lost part of its bulb charge? If you are measuring a correct/high subcooling along with a high superheat and a low saturat...
Quick Tips
Connect Your Gauges Sooner Than Later! (Quick Tip)
When checking the refrigerant charge of a running HVACR system, remember to attach your refrigerant hose to the vapor port right away. Don’t wait o...
Quick Tips
Free Shrader Valve Refrigerant Leak Tester (Quick Tip)
Make a Quick Free Refrigerant Leak Tester for the Schrader Valve (Valve Core) at the Access Port. Drill an 1/8” hole in the end of an extra port ca...
Articles
Why Can’t You Just Measure Pressures to Check a Refrigerant Charge?
Most technicians in the HVAC field know the normal range of operation for the low-pressure side of an air conditioning system. This tends to be aro...
Articles
Using the Total Superheat Charging Method for HVAC Units!
In this article, we will define both superheat and total superheat, calculate total superheat, explain how to use total superheat to check the refr...
Quick Tips
An Additional Valve Core Removal Tool for your Vacuum Gauge! (Quick Tip)
Use an additional valve core removal tool in your vacuum setup to valve off and protect the vacuum gauge sensor from oil contamination when refrige...
Articles
The HVAC Subcooling Charging Method, Explained!
In this article, we will define subcooling, calculate subcooling, explain how to use subcooling to check the refrigerant charge, and show where the...
Articles
Top 10 Thermostat Related Problems
Regardless of the type of system or brand of thermostat, it is important to understand that there are many issues that can prevent a thermostat fro...
Articles
HVAC DELTA T (ΔT) Explained for Air Conditioners!
Delta T is a term that gets thrown around in the HVAC field quite a bit, but what does it really mean, what is its purpose, and does it really matt...
Articles
Filter Drier, Solenoid Valve and Liquid Line Sight Locations in a Refrigeration System
The filter drier, solenoid valve, and liquid line sight have unique responsibilities in an automatic pump down refrigeration system. To use each of...
Articles
Top 4 Reasons Why a Gas Furnace Short Cycles
Short cycling means a gas furnace is running through its full sequence of operation for heat, it is providing heat in the building, and then it is ...
Articles
How the Gas Pilot Light Functions and 10 Reasons Why the Pilot Light Goes Out or Won’t Stay Lit!
Pilot lights can be found on furnaces, water heaters, fireplaces, ranges, ovens and other appliances. First, let’s discuss how the pilot light work...
Articles
Newer Methods that Make us Better Techs and Reduce Labor and Frustration! Top 15!
Newer or faster methods do not always require expensive tools but do require a certain tool setup and step by step procedure. Some of the most labo...
Articles
Understanding Triple Evacuation
The triple evacuation is meant to be a means of dehydrating refrigerant tubing in a system that has high water content before refrigerant is introd...
Articles
Can you Braze Mini-Split systems instead of Flaring them?
I have been asked, “Can we braze mini-split systems instead of flaring them?”. The answer, technically, is yes. The only question is in a warranty ...
Articles
Determining the Cause of a Liquid Line Restriction Problem!
First of all, a liquid line restriction problem can be confirmed by measuring the following before the evaporator coil freezes: Low Vapor Saturated...
Articles
Measuring a Liquid Line Restriction Problem!
The metering device is a purposeful restriction in the liquid line prior to the evaporator. The metering device is needed to lower the pressure of ...
Articles
Troubleshooting an Air Conditioning System with a Frozen Evaporator
When arriving on-site to a frozen evaporator coil and suction line on an air conditioner, you should be aware that at least one of the three follow...
Articles
Should I Check the Refrigerant Charge with Superheat or Subcooling?
If the outdoor unit has a single speed or two speed compressor running in second speed and the unit is not a Micro-channel coil, then Total Superhe...
Articles
Testing Capacitors
An HVACR capacitor can be tested after turning the power off, disconnecting the wiring, and bleeding off any leftover voltage before testing. This ...
Articles
Target Superheat
To determine the Target Superheat for an air conditioning system with a fixed orifice (such as a piston or capillary tube) measure the indoor WB (w...
Articles
The Total Weight Method
This charging method is used for systems that have no refrigerant. It is also used on new systems with a known amount of refrigerant in the outdoor...
Articles
Superheat vs. Total Superheat
Superheat is the temperature increase of the vapor refrigerant from where it turns from the saturated state into a vapor at the evaporator coil unt...
Articles
Heat Pump Pressure Switches
Pressure switches are typically installed in heat pumps and air conditioning systems to protect the compressor from a high pressure situation, to p...
Articles
Recovery Bottle Weight
In order to determine how much refrigerant can be added in a used recovery bottle, first the neck of the recovery bottle must be read. This will sh...
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