Home AC units use motors to move the air and motors to move the refrigerant. Whether due to overheating, a lack of proper maintenance, or old age, HVAC motors can break down and cause the entire system to come to a halt. That’s where you as the technician come in! How much do you know about diagnosing and repairing damaged AC motors?
Common Air Conditioning Motors
Every home is different. In your HVAC career, you’re likely to encounter AC systems ranging from the very old to the factory new. Consequently, you need to understand the different types of motors you’ll encounter and how to properly handle and replace each one as needed. Take some time to familiarize yourself with the 5 motors you’re most likely to encounter:
- Condenser fan motor
- Blower motor
- ECM motor
- Combustion fan motors
- Compressor motors
1) Condenser Fan Motor
Since a condenser fan motor will get rained on and be exposed to the elements, it’s rated for use outdoors sealed up on the ends and sides to keep water out. These motors are usually one speed and come in horsepower ranges from 1/6 hp to 1/3 hp. They always have a capacitor, usually a dual capacitor if it’s an original motor and a single capacitor if it’s a replacement aftermarket motor. The factory motor usually has three wires and the aftermarket version usually has 4 wires.
The main thing to remember on a condenser fan motor is the main service issue is usually a bad capacitor. This issue generally surfaces during summer, when the weather is hottest. If the motor is bad, measure the fan blade height to the finger guard before you ever remove it. The placement of the blade is absolutely paramount to the operation of the condenser, even more so than its original placement on the motor shaft. Consequently, you should always keep any replacement fan blades at the exact same height, since getting this blade height wrong by even an inch can mean the compressor will overheat and burn out. If you need to replace the condenser fan motor and capacitor, take note of these key pieces of information first:
- Frame size
Above all, never try to force the replacement blade onto the motor. After all, a motor is easy to replace while the correct fan blade might take you weeks to find.
Finally, don’t fall back on the assumption that you can simply substitute a different pitch blade when necessary. The wrong size or type will not work and may overheat the fan motor or simply not move enough air, meaning that the AC unit won’t do its job. Airflow at the condenser is critical.
2) Blower Motor
Another popular air moving AC unit motor is the blower motor. The blower motor looks similar to the condenser fan motor, except the blower is ventilated on the sides and/or the ends to allow air to pass through. Blower motors also have a capacitor, in addition to way more wires than condenser fan motors.
The main cause for blower motors failing is that dirty air passed over them and stopped up the vent hole, causing the motor to overheat. This indicates a deeper problem since the air filter should catch dirt before it reaches the motor. Sometimes a blower motor experiences a capacitor failure, causing it to turn backward. They look normal running this way but move almost no air. After a couple of hours, the evaporator coil freezes and the house overheats, prompting the homeowner to call for help.
To replace a bad blower motor, remove the blower housing with the motor and blower. You have to remove the curved plate first, but this is where the wheel slides out of the housing. Make sure to reattach the blower wheel securely when you’re done to avoid burning out your new motor. Finally, remember that blower motors also have universal replacements. Just remember that electric heat furnaces us 230-volt blower motors (in contrast, gas furnaces use 115-volt motors) and you’re good to go!
3) ECM Motor
The ECM motor is a blower motor with an electronic control module mounted on the end. These motors are special; some must be set up at the supply house with special programming. Others have program modules you can buy to do it yourself. A few particularly advanced models even allow you to program the unit from your phone!
ECM motors can cost up to $1000, so be sure to get current pricing before you give your client a quote. Beginning HVAC technicians may benefit from getting an expert technician’s input on how to handle ECM motor repairs since, considering their high price tag and complicated inner workings, trial and error is not the way to go with ECM motors. When you’re dealing with equipment this expensive and advanced, it’s better to be safe than sorry.
Pro Tip: If you get stuck on an HVAC job and can’t get hold of an expert, call the AC motor’s service number to talk to a brand representative. They’re usually willing to help you out.
4) Combustion Fan Motors
Combustion fan motors are found in gas furnaces. These types of motors don’t have a capacitor, just two wires. It’s very easy to diagnose what’s wrong with a combustion fan motor. If the motor is receiving its full 115 volts but not running, it’s burned out and the whole thing likely needs to be replaced. You can usually buy replacement units from factory brand reps.
Since these motors tend to last as long as the gas furnace they’re installed on, you likely won’t see too many combustion fan motor failures. But even when you do, the replacement won’t take you very long and will be a pretty straightforward process.
5) Compressor Motors
The most expensive and hardest to replace of the air conditioning motors is the compressor. This motor is sealed inside the compressor housing, so you can’t determine visually if the motor has failed. The only parts you can test are the three terminals sticking out of it.
Compressor motors are really two motors in one: the start motor and the run motor. They just happen to be connected together at the common wire terminal. The start windings are very small wires that are wound on the motor to deliver a quick burst of power and start the motor. Since the start windings are only designed for the initial spark. if the start windings have to work for more than about three seconds, they’re likely to burn out. The motor’s run capacitor ensures the start windings don’t work too hard and keeps the entire motor running correctly.
While this is an expensive part to misdiagnose (a new compressor can cost up to $1000 wholesale), don’t panic. It’s difficult to correctly diagnose a motor you can’t see, so the majority of problems with compressor motors come from misdiagnosis rather than equipment failure. Using a meter, test each of the three terminal connections to see if they display the proper resistance sums and have any charge to ground. If there is any reading to the ground, the motor is bad.
Be sure to always remove the power and discharge any capacitors in the unit. The compressor might not read anything when you test it–this is when 90% are incorrectly condemned. The truth is that compressors have an internal safety switch that turns the motor off when it overheats, and if you test the motor while the switch is activated, it’s easy to assume the motor has burned out. With this information in mind, never rush to the assumption that the compressor is burned out. Compressors should last the life of the unit. Before you try to replace the motor, try to determine the cause of failure or see if the safety switch eventually deactivates.
AC Motor Replacement & Repair
Knowing the normals of each common type of HVAC motor is a critical first step in developing your long-term HVAC career. Take the time to familiarize yourself with the most common types of motors and learn how to repair or replace each as necessary. As you build your understanding of air conditioner systems and maintenance, you’ll become better at your job as a technician.
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Are digital gauges necessary? This is a question that comes up a lot, and there are a wide variety of opinions. After all, the HVAC industry doesn’t seem to favor one style over the other. Why is one any better than its alternative?
Most HVAC technicians should keep at least two sets of gauges, and potentially three depending on their exact work. Different types of HVAC units may be more compatible with different gauges. Consequently, there isn’t really a clear answer to the question of which gauge type is superior, if at all. Let’s take a closer look at both types and their potential applications to find the right answer for your situation.
Different Types for Different Work
You need two, possibly three, sets of gauges depending on what you are doing. Some techs like to have one set for 410 refrigerant machines and another for R22 machines. However, we have so many different types of refrigerants now it’s not practical to have a set of gauges for each. One set of digital gauges and one back up set of analog gauges is all most people will ever need.
Using Digital vs. Analog Gauges
Digital gauges are far superior for testing and adjusting the charge, and they’re absolutely imperative if you want accurate superheat and subcooling readings. Digital gauges have temperature clamps that connect to the liquid line and suction line and have built-in pressure-temperature charts. You simply tell the gauge set what refrigerant you are testing, hook up the hoses and temp clamps, and get live instant readings of superheat and subcooling. The margin of error is remarkably low.
If you use analog gauges to perform critical charging, you will have to read literally between the lines of the needle and the gauge lines. Once you guess the pressure reading, you must then use a pt chart to obtain the temperature equivalent. After you get that number, you have to actually take a temp reading of the appropriate line and subtract those two numbers. Along the way, chances are you will either misread something, make a mistake in the math, make a pt chart conversion mistake, or several of the above. Even if you manage to get all that correct, there’s a good chance that the system pressure or temperature changed between all the readings. This change alone will lead to inaccuracies of four to five degrees. When you are talking about subcooling number targets of 10 or 12 degrees and you miss it by six, that’s a significant margin of error.
What Do Industry Professionals Prefer?
Some brand manufacturers require the dealers to charge with digital gauges if they want to continue and sell that brand. Usually, these policies exist because manufacturers have received warranty returns due to improper charging methods rather than actual problems. Consequently, the requirement for digital gauges is a (generally successful) attempt to combat these warranty returns and preserve business.
Analog gauges have their place, however, especially if you are working on a system that has a bad burn out and has turned the oil into acid. You will not want to pull this into your $400 digital gauge set, so you whip out the trusty analog set. The analog is also a great back-up set when your digital set goes out.
Pro Tip: Different brands of digital gauges may have varying features, but overall, they all work about the same. Just find the brand with features you like the most.
Neither is Always Better
To summarize, there is no way to state for certain which type of gauge is better. While digital gauges are more convenient and generally preferred by HVAC professionals and manufacturers, sometimes an old-fashioned analog gauge works just as well or even better. The ultimate deciding factor is preference. To make sure you always have the type you or a client prefer, maintain a set of each type of gauge just in case.
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The vast majority of American homes with HVAC systems use R22 refrigerant in the coolant system. Historically, this coolant has been regarded as the most effective and the best overall value, contributing to its widespread use. Plenty of HVAC technicians still highly praise this refrigerant and use it in all their work. However, is R22 really everything it’s claimed to be?
A growing number of HVAC technicians and industry experts are beginning to turn to alternatives to the R22 refrigerant. Whether they cite environmental concerns, chemical differences, or any of a number of other reasons, it’s worth looking closer at their questions about this so-called king of refrigerants.
Almost since the invention of home air conditioning, R22 has been the nearly-exclusive refrigerant most people used. If not for its environmental dangers, it would probably still hold that title. The ingredients in R22 are known to damage the ozone layer and contribute to greenhouse gases. Even after the problem was discovered and a solution agreed upon, the deadline for a resolution has only recently begun to loom and prompt quick action.
Alternatives to R22
The puron refrigerant R410A, which was significantly safer for the environment, slowly began to gain prominence with time. Reluctant technicians stayed away from R410A at first, citing a host of reasons it didn’t work. Others pointed out that because of their different chemical compositions, R410A produced higher pressure than R22, making the compressors work harder in an HVAC system. R410A also contains caustic POE oils instead of the much safer mineral oil used in R22.
As the deadline approached, many manufacturers had to stop producing machines designed to use R22. Consequently, more and more technicians sought out alternatives such as R410A. However, many continued to cite bad results and blamed the new refrigerant rather than a lack of effort to change. Many still tried to purchase R22 for their work, causing the price to skyrocket from $50/jug to more than $900.
What This Means for Your HVAC Career
Chemists had developed a host of alternatives that could be used in R22 units, including several refrigerants with a near-perfect match on performance and pressure. Today, there are at least 10 refrigerants available that either match or outperform R22 in its refrigerant properties.421A in particular shows great promise. Why spend hundreds of dollars on an environmentally unsafe compound when you can save money and the earth through buying an alternative refrigerant?
Of course, many of your clients will still have older machines that use the original types of refrigerants or an alternative to R22 that you may not have heard of. Before you buy any new refrigerant for a client or suggest a top-off of what they have, make sure you know exactly what type they’re currently using. Putting in the wrong compound could damage their HVAC unit and cause terrible warranty problems for you as the contractor.
Pro Tip: Different units will use different types of refrigerants. Make sure to educate yourself on the most common types and their pros and cons so you can help your customers make an informed decision.
Finding the Right Refrigerant for the Job
The modern world changes rapidly, and the HVAC industry is no exception. Refrigerants will come and go as more cost-effective and environmentally friendly options are developed. Always be willing to compare your old favorites to new products. You may be surprised to see that what was once the gold standard now takes a backseat to a new arrival, much like the R22 refrigerant is phasing out of the industry.
Connect with us to learn more about different HVAC refrigerants and how to best use (or avoid) them in your career.
The HVAC unit is one of the most expensive systems in a home. As a result, homeowners do everything they can to keep it running efficiently and properly. While they may be comfortable checking their thermostat and changing the air filters, there are some situations that require reliable, professional HVAC and air specialists. That’s where you come in! Unfortunately, some HVAC techs and business owners aren’t paying attention to the crucial factors that customers look at when choosing a company.
Local HVAC Company
Homeowners are savvier than ever when it comes to identifying, comparing, evaluating, and eventually dealing with contractors and HVAC companies. They understand that doing their research can mean the difference between getting a professional tech and just getting ripped off. As a result, be prepared to beef up the following:
It would not be a stretch to say that 99% of homeowners Google your business and your competitors before they ever pick up the phone. Google, Facebook, and Yelp are good, reliable sources for finding company and employee reviews. Customers especially value specific examples of honesty, customer service, and value. Encourage customers to call or text you with any negative experiences so that you can remedy the situation offline before dissatisfied customers vent online and hurt your ratings.
Older customers care more about how long you’ve been in business than younger homeowners, who generally care more about reviews. That being said, an HVAC company that’s been in business for 25 years should still reinvigorate the workforce with younger HVAC technicians. Most customers don’t think about the fact that HVAC technology is evolving and changing, so often times younger techs right out of HVAC training school will be more up to date on new technology and techniques than older techs.
When homeowners have an issue with their HVAC, it’s usually in the peak summer months or in the dead of winter. This means that they’re either stiflingly hot or freezing inside their home, and will want the problem fixed right away. That can be a challenge for some companies, as these are your peak HVAC seasons and many technicians are overextended. Ensure you that you don’t overpromise and underdeliver when it comes to setting a timeline for the customer.
Pro Tip: Be honest with customers about your timeline and they will be less likely to get frustrated and find a different company. Don’t sugarcoat your time estimations!
Think Like Your Customer
There are many factors within the HVAC industry that are important to you and your business but are not as important to your customers. Learning to think like your customers will help you identify those aspects of your marketing and business plan that need to be improved.
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You probably already know that HVAC stands for Heating, Ventilating, and Air Conditioning. But do you really know how an HVAC system works? The primary function of the HVAC system in your home is to provide temperature control and produce acceptable indoor air quality (by controlling humidity and filtering the air).
Understanding Your HVAC System
Understanding the basic functions of an HVAC system and how it works is important to maintaining your current system in good condition. Whether you’re troubleshooting a problem or wondering if you need the help of a trained HVAC technician, understanding the basics helps.
- Evaporator Coil
- Condensing Unit
Usually installed on a prominent location on an interior wall, the thermostat can be set manually or programmed to keep your home at your ideal temperature. When the temperature inside gets too hot or cold, the thermostat triggers your HVAC system to start circulating air as needed.
Your furnace is usually the biggest component of your system, requiring a designated closet or space in your garage or basement. All furnaces consist of four main components: 1) burners that deliver and burn fuel, 2) heat exchangers, 3) a blower and 4) a flue that acts as an exhaust for gaseous by-products.
3) Evaporator Coil
The evaporator coil is used to cool down the air when your thermostat is set to a lower temperature. This cold air is then funneled throughout your home.
4) Condensing Unit
This large unit is found on the outside of your home and filled with what is called refrigerant gas. When the refrigerant is cooled, the condensing unit pumps this liquid to the evaporator coil to be transformed into gas again.
These are the outlets that help distribute heated and cooled air from the duct system into the various rooms of your home. They’re generally found near the ceiling with angle slats, designed to send the air downward.
These lines carry refrigerant to the condensing unit in the form of gas. This gas is transformed to liquid form, then transferred back to the evaporator coil.
These lines carry refrigerant to the condensing unit in the form of gas. This gas is transformed to liquid form, then transferred back to the evaporator coil.
Trust an Expert
These are the basic components of your HVAC system, but if you’re experiencing an issue with your heating or cooling, it’s best to call an expert. DIY repair can be costly and dangerous.
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An HVAC tune-up can save you money by identifying inefficient energy usage, can reduce the risk of carbon monoxide poisoning on gas heating systems, and can also eliminate neglected problems leading to system failures. To ensure that your heating and cooling system is running at peak efficiency, you should have it checked out by a professional once or twice a year.
HVAC Tune-Up Checklist
Most homeowners aren’t experienced or equipped enough to complete an HVAC tune-up without professional help. However, there are certain checks and preventive measures that every homeowner can do to prevent damage to your HVAC system.
Keep It Clean
Make sure that your AC unit if clear of any debris or lawn growth that could damage it or cause an electrical short. The AC condenser should not be covered up, even though you may not love the way it looks! It needs plenty of fresh air to pump into your home.
Off the Ground
Ideally, your outdoor AC condenser unit should be off the ground, protecting it from potential flood damage or animal activity. If it’s not, you may need a professional to mount a wall bracket or concrete lift.
Change Air Filters
Changing your home’s air filters is essential to your air conditioner’s efficiency. Forgetting to change your air filters can damage your HVAC equipment and cause costly problems. Typical filters should be changed every 30-90 days.
The Professional Advantage
Your HVAC system is a complex network that needs a professional for nearly all repairs. Never attempt to repair your unit or ductwork armed only with a YouTube tutorial video. The risk of injury from electric shock, fall or hardware misuse is high if you lack the experience and training of an HVAC technician.
Contact Us to learn more about hiring a skilled HVAC technician, or becoming one yourself!