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’s to look capable. Here is how to balance a sharp presentation with a "ready-to-work" attitude. 1. The Logistics of Professionalism Professionalism starts long before you shake hands. Your arrival sets the tone for your reliability in the field. The Golden Rule of Time: If you’re on time, you’re late. Aim to be early. The Dry Run:

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 pieces of wood with 26 measurements labeled A-Z. Each piece has two letters, one for each dimension to be measured. I then give each student a fraction layout sheet for an inch and another sheet that they can write their answers on for each letter measured, A through Z. I explain the 1/2", 1/4", 1/8" and 1/16" fractions, full one inch

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 Metering Device during operation. Using water as the liquid during this experiment helps them visually see this in action! Why does the TXV Matter? A TXV (Thermostatic Expansion Valve) can change the amount of liquid refrigerant traveling into an evaporator coil to absorb heat. This regulation device allows the system to act in an eff

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 there is air skirting around the air filter because its not snugly fit, the dust will collect on the side of the indoor evaporator coil. Eventually, enough dust collects onto the coil to significantly reduce the amount of airflow crossing through the coil fins. This reduces energy transfer, increasing electricity bills and reducing

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 evaporator coil , static pressure measurements can be used to determine if the pressure drop is too high. This is a quick way to determine how blocked off the under side of the coil is. The higher the pressure drop, the more restricted the coil. The more restricted the coil, the lower the CFM of airflow crossing the coil. The lower t

Measuring airflow is one of the most commonly missed or ignored topics in HVAC when commissioning or diagnosing problems in systems. I don't believe this topic is purposely ignored due to lazyness or just wanting to reduce the time on service calls. I believe it actually stems from the lack of easy to follow methods, and a lack of accuracy in some methods due to either system design or tool limitations. Below are possible methods or tools to measure airflow in HVAC systems: T

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 can have long term health effects depending on exposure time, the health and age of the exposed person. Carbon Monoxide binds with the hemoglobin in the blood 300 times more than Oxygen. It is believed that Florence Nightingale's ailments may have stemmed from CO poisoning from her coal heater in Russia. Some haunted houses were actu

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 reasons a package unit may lose power, but fortunately determining if this is the problem can be done fairly simply. First, remove the cover plate of the package unit to look at the control board. If the LED light on the control board is lit, there is power to the unit and the problem is something else. If the LED light is not lit, t

This article covers the ten most common locations where refrigerant leaks may be on an air conditioning system. An electronic leak detector is typically used to find the general area of the leak and non-corrosive bubble leak detector is used to pinpoint the leak. In the following pictures, an Accutrak ultrasonic leak detector and Big Blu non-corrosive bubble leak detector are used to search for and find refrigerant leaks. A ultrasonic leak detector (see photo below) locate

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 HVAC/R experience and are relying on prior job experiences, a professionally made resume, and the interview process to land the job. As in any field of work, there are certain interview strategies and techniques that will help you get hired. This article covers ten top interview tips when applying for a career in HVAC/R. A successf

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, air handler, or packaged unit. There are multiple reasons why the motor won't start and these are based on the type of unit, controls, and the blower motor type. Problem # 1: Capacitor When an HVAC unit is equipped with a PSC (Permanent Split Capacitor) blower fan, a capacitor is required to both start and run the motor. The cap

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 an accumulator tank (left) and an accumulator tank mounted on the side of a rotary compressor (right) . Uses of an Accumulator Tank An accumulator tank is factory installed on the following: Heat pumps as a storage tank because during heating mode there may not be as much refrigerant needed as when in cooling mode. Some outdoor c

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 solder connection. Swaging is a method used on ACR (Air Conditioning, Refrigeration) copper tubing for refrigerant as well as soft copper tubing used for plumbing. Swaging is done to reduce the amount of brazed or soldered joints in a tubing run. In the case of a coupling, two braze joints are needed, whereas with a swage, only one

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 conditioning units. It can be identified by its cylindrical shape and black plastic body. These are often used in a system design where the unit must operate during low outdoor temperature conditions and/or when there is a non-bleed TXV installed in the refrigerant circuit. A non-bleed TXV does not allow the refrigerant pressures

Basic Characteristics of a Good Instructor "The hardest year of teaching is the one you are currently in." - Ty Branaman Based on their experience, Ty Branaman and Craig Migliaccio believe the following characteristics, strategies, behaviors, and habits make a good instructor. Tip #1: A good instructor cares. People matter to the instructor. Therefore, the instructor care

If a furnace or air conditioning system develops an airflow problem, there are several items to visually inspect. If visual inspection does not locate the issue, proper testing tools are required to determine where the problem is and how severe it is. First visually inspect the air filter to see if it is dirty or clogged. Replace if it is too restrictive or clogged. The back of the evaporator coil could become clogged if there is no air filter or the filter is dirty. The evap

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 outdoor air into the attic from either the side gable vents or from the lower holes in the soffit. The fan then pushes the air out the attic through its penetration hole in the roof. The object is that fresh air (at the same temp as the outside air) is moving through the attic. Otherwise, non-circulating air would remain trapped wit

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 ratcheting type tubing bender, a spring tube bender, or by manually bending the tubing by hand. Step-by-step instructions for tube bending are listed below. Small Lever Type Tube Bender 1. Small Lever Type Tube Bender : This type of tube bending tool is designed to bend soft copper tubing with an OD of ¼”, 5/16”, or 3/8”. The copper

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 our water, these fuels are constantly around us and as installation and service technicians, it is critical that we be aware of how to safely and accurately pressure test gas lines to test for and prevent potential leaks. In this article, we will be using the IFGC ( International Field Gas Code) 2021 as the reference and discussin

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 turning the power off to the furnace or opening the doors to the furnace, check the LED status code light (if equipped) for any error codes. On the furnace, there should be a correlating error code list. This will help in the initial diagnosis of the problem. Reason #1: One of the 24v Electrical Safety Switches Inside the Furnace H

This article explains how to troubleshoot a refrigerator or freezer compressor that does not start. There are different components that can be tested to find out what the problem is. To begin troubleshooting, turn the power off to the compressor. If there is a plastic faceplate over the compressor tabs, remove this. There may be multiple different components inside that are mounted onto the 3 compressor tabs. Below are different examples of what may be found inside. Later in

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 times, compressors are condemned without taking the proper measurements to verify that they are damaged. To help prevent this, I wanted to cover how to check and test various compressors. A multimeter is needed in order to measure electrical resistance at each of the following steps. Before doing any testing on the compressor, make su

A Cad (Cadmium Sulfide) Cell is a photo conductive flame detector that changes its electrical resistance depending on how much light is available at the sensor. This is a common flame detection device used on fuel oil fired burners. The Cad Cell is used in conjunction with an Oil Primary Control mounted to the oil burner. When the Cad Cell is mounted inside the oil burner and the oil burner is off, the location is dark and therefore the resistance reading between the two yell

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 the outdoor unit compressor and outdoor fan for air conditioners and heat pumps. First, let me briefly explain what the contactor is and how it works. HVAC contactors typically come as single, double, or triple pole. This refers to the amount of poles it can switch on or off. The switching action occurs when powering the lower coi

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 port cap. C&D Valve CD3830 Universal Locking Cap Removal Tool with 3 Bits Be Prepared! A Locking Cap Multi-Key can save you a ton of time and frustration. Trust me, if you don’t have the key, you won’t be very happy! More importantly, you don't want to be the tech who is trying to cut a locking cap off with a Sawzall or some other

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 that must be performed for the refrigerant tubing to prepare for refrigerant. When replacing an existing system, start at Procedure 1 . When installing a new system, start at Procedure 2 . Remember, under US federal guidelines, technicians must be EPA 608 certified before handling refrigerants. Procedure 1, Recover or Pump Down: I

Downloadable Wiring Diagrams and the measurement layout are available at the bottom of this page. Instructors are always looking for a low cost, hands-on project, that is safer to teach their students about HVAC Electrical Wiring, Components, Thermostats, Thermostat Wiring, and an Intro to Electrical Troubleshooting! This small electrical training board can be built by each student and it allows each student to get some hands-on training. The teacher can provide the step by s

The question we are looking to answer is, should we install the TXV bulb before (upstream) or after (downstream of) the external equalization port? The first thing to know is that the TXV controls the amount of refrigerant flowing into the evaporator coil. The TXV is a metering device that restricts the flow of refrigerant. The TXV measures and adjusts to maintain a specific superheat. It does this by using three pressures. TVX Bulb Pressure (opening force) External Equalizat

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 torque/multi-speed blower motor. These blower motor versions can be found in furnaces, air handlers, and packaged units. This is a follow-up to our other article on " Adjusting the Furnace/AC Airflow Speed on a 120v PSC Blower Motor ". If you have not read that yet, I would encourage you to do so! To start, ECM stands for Electr

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 units. PSC stands for Permanent Split Capacitor and these motors can be easily identified by their direct connection to a capacitor. Remember that CFM stands for Cubic Feet Per Minute. Roughly 400 CFM is needed for every 1 ton (12,000 BTU/HR) of heat removal capacity in air conditioning systems. 350 CFM per ton can be used in humid cl

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 occur that causes the pilot flame to go out along with the solution for each example. The following steps indicate how to light the pilot on the water heater and explains the key components within the water heater that make it work. Lighting a pilot should be fairly simple. 1. Locate the large red/white knob on top of the water heat

In this HVACR Training article, we are using electrical resistance measurements on the PSC compressor terminals in order to determine which tab is Common, Start, and Run. This is used when the tabs are not labeled, there is no plug for the terminals, or there is no electrical wiring diagram available for the wires feeding from the terminals. The steps listed below can be used to test all single speed PSC motors (i.e., compressors, blower motors). Whenever possible, first meas

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 rollout switch, thermal limit switch, and the pressure switch. The gas furnace is designed with at least one flame rollout switch to detect flames or high temperature within the combustion chamber. The flame rollout switch is normally closed and opens on high temperature from the flame. The switch is meant to open if the flame is pus

In this HVAC training article, I discuss 20 AIRFLOW Problems that you may find on ducted gas furnaces, air conditioners, heat pumps, air handlers, and packaged units. Some problems happen over time due to lack of maintenance while others may have occurred during the initial installation. Low air flow is a big deal, so it is important to figure out what is causing this issue. For a furnace it could overheat. For an air conditioning system, the evaporator coil could freeze. If

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 shortcut to the ground or common that requires little or no resistance, rather than completing the designated path. In an HVAC system, low voltage shorts are often indicated by a blown fuse on a control board or in the circuit wiring. Unfortunately, knowing that a short exists is only the first step. The fuse acts as a safety on the h

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 the right leak detection tool is used. If a leak exists in a system, the leak may be anywhere such as in the condenser, evaporator coil, line set, or a fitting, component, or joint. Searching all of these areas must be done quickly and with confidence. Regardless of the type of gas within the HVACR system, an ultrasonic leak detec

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 Cooper&Hunter Dakota Series Hyper Heat model . This installation process will be very similar to other manufacturer’s Mini-split systems. However, it essential to read the install instructions and flare torque specs of the exact model you are installing. A variety of tools and techniques are needed to complete the installation of

In order to troubleshoot a gas furnace, the technician must have a thorough knowledge of each component that could be in the unit. Understanding how each component works is crucial to fixing the problem! Let's start by going over each of the major components down below! Integrated furnace control board: This board integrates both the ignition control with the blower control all as one board. Depending on the 24v inputs on G, W, Y terminals, it will control the function of the

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 make the job a little easier. It is difficult, if not impossible to know if a control board is bad if you don’t know how the system it is attached to works. For a furnace, you need to know the sequence of operation for the heat to turn on. ( Check out our video on that .) For an air handler, you will need to determine if the unit i

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 other, this means that there is a pressure drop. Remember that temperature follows pressure and temperature is something that we can measure on the outside of the tubing. Usually no ports are available at the inlet or outlet of the liquid line filter drier. Filter driers are designed to have an extremely low pressure drop across t

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 without reaching the desired temperature, you can check the total superheat to determine if it is low on refrigerant. I have noticed that on most properly charged systems, the total superheat tends to be between 0 to 5 degrees during emergency cool and full speed cooling. The reason that the system can run with this low of a total superh

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 when trying to figure out solutions to vacuum problems! I am happy to say that I no longer have issues with my vacuums and if there is a problem, I can usually figure out the solution quickly without frustration! Below are my top 40 tips for techs when pulling a vacuum! Hoses 1. Hoses may be rated for vacuum or just for positive press

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 temperature. For single and two speed compressors systems, we use the subcooling and total superheat charging methods. I will briefly explain these charging methods using pressure before diving into reading temperatures only in order to check the charge. In order to measure subcooling, we measure the saturated temperature in the

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 important to know the range of these pressures in order to understand why and how charging and recovery are performed. The first thing to realize is that when a system is off and equalized, the system’s pressures on both the high side and the low-pressure side will match. In the example of an R-410A packaged unit with a surrounding

In a dry climate, certain considerations must be taken prior to installing or servicing air conditioning systems. A TXV metering device and an accumulator are important factors. In a dry climate, a TXV metering device should be installed instead of a piston metering device. Not only is this important for efficiency, the TXV will help protect the compressor somewhat during low indoor humidity and high outdoor ambient temps. The TXV does this by keeping the superheat steady at

There are many ways that technicians have tried to get around actually checking the charge of air conditioners and heat pumps with superheat and subcooling! I go into great detail explaining methods that you should use and methods that you should NOT use in the book “Refrigerant Charging and Service Procedures for Air Conditioning”. In this article I just want to highlight some of these shortcut methods to give you a taste of what junior techs are being told and may be choosi

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 they connect the indoor head unit to the outdoor heat pump or condensing unit. Two flare connections are needed at the indoor head unit and two flare connections are needed at the outdoor mini-split unit. Things to consider: · A standard system has four flare connections while a multi-zone system has more flare connections for the a

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 a conventional air conditioner or heat pump?". The answer is not exactly, but you can do some troubleshooting. A mini-split differs from a standard central air conditioning system in a variety of ways. Conventional split systems usually have a TXV (Thermostatic Expansion Valve) or a piston metering device, a single or two speed com

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 around 60 PSI to 85 PSI for R-22 and 105 PSI to 143 PSI for R-410A and is dependent upon operating conditions. On the high-pressure side of the system, there is a wide variation in pressure due to the wide outdoor temperature swing and due to the actual SEER (Seasonal Energy Efficiency Ratio) rating of the system being worked on. Beca

In this article, we will define both superheat and total superheat, calculate total superheat, explain how to use total superheat to check the refrigerant charge, and show where the measurement points are taken on an air conditioning system. Total Superheat Formula: Actual Vapor Line Temp – Sat Temp = Total Superheat So what does this mean and what is the difference between Superheat and Total Superheat? Simply put, superheat is the increase in temperature of the vapor ref