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Know the Normals: How to Identify HVAC Problems

Know the Normals: How to Identify HVAC Problems

Know the Normals: How to Identify HVAC Problems

Why is it so important to understand what a normal HVAC system looks, sounds, and feels like? Simply put, you must know normal before you can diagnose abnormal. Adopting this philosophy will have a profound impact on how you see and work on almost everything.

No matter what you are doing, if you know what is normal, you will be much more confident in the outcome. Technicians that don’t realize this tend to make many mistakes, incorrect diagnoses, and improper installations. What impact will this have on your HVAC career?

Do you know what a normal #HVAC system looks like? Can you identify potential problems based on that knowledge? Here’s why knowing what normal HVAC equipment looks like is so important. Click To Tweet

Normal Isn’t Always Good

It should go without saying that normalcy in an HVAC system isn’t always a good thing. For example:

  • It’s normal that most a/c systems are installed incorrectly.
  • It’s normal for technicians to ignore superheat and subcool when charging or testing a system

Even if being normal isn’t always a good thing, it’s still important to recognize what a normal system looks like. If you know that most systems are installed incorrectly, it will make you look harder and not assume anything. If you know that most technicians ignore proper charging procedures by ignoring superheat and subcooling, you will take a closer look at that even though you may be there for something entirely unrelated to the refrigerant charge.

Identifying Abnormalities

Sometimes knowing normal is knowing how something reacts when it fails. For example, if a liquid line drier starts to clog up, it’s normal for a temperature drop to be detectable from the inlet to the outlet side. It’s also normal for a clean drier to not have a temperature drop. Both of these are the norm for that particular situation, but both equally important to know.

On the other hand, two seemingly opposite functions could also be normal. For instance, an evaporator coil will produce a large amount of water if the air is high in humidity, and none at all if the weather is dry. If you don’t know the difference, you might misdiagnosis a problem based on incorrect knowledge of what the system is supplied to do. Just the fact the coil does or does not produce water means nothing if you don’t understand the differences.

Pro Tip: Even if you notice fluctuations in certain HVAC functions, don’t assume that means there’s a problem. The system may be designed to handle or cause those changes. Stay informed of real problems to watch for.

“Normals” of HVAC Compressors

How much do you know about the normal functions of HVAC compressors? Let’s just consider the temperature of the shell of the three compressors. The scroll on the top of the compressor should be very hot since that’s where the head discharges into the dome. In fact, the entire dome should be very hot anytime the unit is turned on, while the sides are cooled by suction gases and will not be nearly as hot. Since the reciprocating compressor is also cooled by suction gases, you should only notice heat where the hot gas line leaves the shell.

If a technician touches a rotary and assumes it is overheating because he confuses it with a scroll, they’ll misdiagnose a system issue and perform unnecessary work. Similarly, touching a hot reciprocating compressor and assuming it is operating normally because you don’t know better will allow a potentially severe problem to get worse.

Know What a Normal HVAC System Looks Like

It’s been said that “You must know normal before you can know abnormal”. This saying is particularly true in an industry that deals with troubleshooting. The first step toward identifying a problem is knowing what normal operations should look like and what any deviations from the norm could mean.

Connect with us to learn more about normalcy in the HVAC industry and how to identify common issues.

How a Basic HVAC System Works

How a Basic HVAC System Works

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). In Houston, people rely on their HVAC system to keep them cool in hot summer months. But do you know how the system works? Click To Tweet

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.

  1. Thermostat
  2. Furnace
  3. Evaporator Coil
  4. Condensing Unit
  5. Vents
  6. Refrigerant
  7. Filters

1) Thermostat

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.

2) Furnace

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.

5) Vents

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.

6) Refrigerant

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.

7) Filters

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.

Interested in becoming an HVAC tech? Contact Us to learn more or to sign up for classes.

Understanding the Differences Between Residential and Commercial HVAC

Understanding the Differences Between Residential and Commercial HVAC

The basic idea behind all HVAC systems is the same.  Cooldown buildings, absorb moisture during the evaporation phase and lower humidity, providing a pleasant environment for those inside the space. However, this doesn’t mean that these 2 systems are the same.Residential and commercial HVAC have different requirements, from energy and space to repair. Click To Tweet

Residential vs. Commercial HVAC

While residential and commercial HVAC systems have similar technology, there are significant differences between the two. This includes the amount of power they require to operate, size, location, complexity, and drainage. These key differences also mean that technicians must receive different training for commercial and residential HVAC repair and maintenance.


  • Residential HVAC systems split, with the blower, evaporator, and condensation drainage unit inside the home and the compressor, condenser and condenser fan unit located just outside the home.
  • Commercial units are housed together (package units) on the facility’s rooftop or in a large cabinet. This allows technicians to work on them without disrupting those inside the building, and it keeps the system safe from vandalism or other damage.


  • Residential units generally only require one condensation pan that drains to the outside, with windows to alleviate exhaust.
  • Commercial HVAC systems are very complex. They heat and cool a much larger area, so require a more elaborate draining system.

The Same Goal

Residential and commercial HVAC systems are not the same, but both function to reach the same goal, which is to provide a comfortable space. Whether it’s for yourself, your family, customers or clients, it’s important to schedule HVAC service calls with a technician capable of fixing your unique system.

Contact Us to learn more about finding a qualified residential or commercial HVAC technician. Interested in becoming a certified HVAC technician? We offer flexible classes, financing options and hands-on experience that’s proven to get you hired after graduation. 

The Homeowner’s HVAC Tune Up Checklist

The Homeowner’s HVAC Tune Up Checklist

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. There are many preventative measures you can take to extend the life of your HVAC system. Click To Tweet

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!