Troubleshooting Common HVAC Problems: What You Should Know

If you want to pursue a career as an HVAC technician, then one of the most valuable skills you will need to develop is your ability to troubleshoot common HVAC issues quickly and effectively. Heating, ventilation, and air conditioning systems are complex systems that require a systematic approach to identify and resolve problems. Whether you’re dealing with insufficient cooling, noisy systems, or uneven airflow, understanding the root causes and how to address them can save time, money, and frustration for both you and your clients. 

In this article, we’ll provide a brief overview of some of the most common HVAC problems technicians face when in the field, and offer practical tips for troubleshooting them.

Insufficient Cooling or Heating

HVAC technicians are at their busiest when the weather turns excessively hot or unbearably cold because it is during these times when more customers start calling in complaining about their systems not producing cooled or warmed air. There can be several reasons why an HVAC system isn’t cooling or heating a home adequately enough and some of the most common include:

• Dirty Air Filter: Clogged filters restrict airflow, thus reducing the efficiency of the system. To troubleshoot, check the filter’s condition and replace it if it’s dirty. Filters should typically be replaced every one to three months, depending on certain factors, such as usage, whether or not there are pets in the home, location, and more.
• Refrigerant Leak: Low refrigerant levels can compromise a system’s cooling capacity. To troubleshoot, use a refrigerant gauge to measure pressure and identify leaks. If a leak is found, repair it, and recharge refrigerant as needed.
• Thermostat Issue: Incorrect thermostat settings or faulty wiring can lead to improper temperature regulation. To troubleshoot, examine the thermostat to ensure it’s set to the correct temperature and check for loose or damaged wiring.
• Dirty Coils: Evaporator and condenser coils that become covered in dirt will reduce the system’s ability to transfer heat. To troubleshoot, check the condenser coils and if they’re dirty, then use a coil cleaner to remove dirt and debris from the evaporator and condenser coils.

HVAC System Not Turning On

Occasionally, an HVAC system will just refuse to turn on. This can be caused by a variety of different issues but the most common tend to be centered around the system’s power source, thermostat, and blower motor.

If an HVAC system is having power supply issues, then the first thing you will want to do is verify that the system is plugged in. Next, check that the circuit breaker hasn’t tripped, and/or that the fuses are intact. If it is not a power supply issue, then deeper troubleshooting will be required.

In many cases where an HVAC system won’t turn on, a malfunctioning thermostat is to blame simply because it fails to signal the system to turn on. To troubleshoot, check and test the thermostat to ensure that it is wired correctly and is receiving and sending the appropriate voltage. Sometimes, simply replacing the batteries in the thermostat is all that’s needed to get it working again.

Problems with a system’s blower motor can also be to blame for the system not turning on. This is because if the blower motor is damaged, then the system won’t circulate air. To troubleshoot, inspect the blower motor. With the power off, try to spin the squirrel cage to determine if the motor is seized. Listen for unusual noises or test the motor’s continuity with a multimeter. Replace the motor if necessary.

Uneven Airflow

Sometimes a home’s HVAC system can operate unevenly. When this happens, some rooms may be warmer or cooler than others, and this can negatively impact the overall comfort of the home’s residents. The most common reasons for this problem include:

• Blocked Vents: It is all too easy for furniture, rugs, curtains, or other debris to obstruct airflow if the homeowner isn’t paying attention when decorating a room. So, cross the easiest solution off the list first by ensuring that all vents and registers are free from blockages.
• Duct Leaks: If all the vents and registers are open and free of blockages, then there may be cracks or loose connections in ductwork that are causing the air loss. To troubleshoot, inspect the ductwork delivering air to the impacted part of the home and use duct tape or mastic sealant to repair any visible leaks in the ductwork.
• Imbalanced System: If the above issues are not the cause of the uneven airflow, then there may be a more serious issue at fault, namely a poorly designed or outdated duct system. To troubleshoot, evaluate the ductwork system’s design to see what needs to be done to rebalance the system. If you do not yet have the skills to perform this task, then consider consulting a more experienced professional to help assess and rebalance the system.

Noisy HVAC System

HVAC systems have a lot of working parts and over time, these parts can start becoming noticeably louder. As a result, noisy HVAC systems are common customer calls. The good thing is that excessive noise doesn’t always mean that the issue is a major one. In fact, more common than not, the cause of a noisy HVAC system is one of the following:

• Loose Components: HVAC systems vibrate a lot when they operate and over time, this vibration can cause certain parts to start to loosen and this creates rattling or banging sounds. To troubleshoot, turn the HVAC system on and determine where the sounds are coming from. Inspect the system for loose panels, missing or loose screws, or other parts and secure them. 
• Dirty Fan Blades: Despite the air filter preventing the bulk of the dust and debris from reaching the fan, you will find that the motor still gets dirty. And when too much dust and debris collects on a fan’s blades, it can cause imbalance and noise. If dirty fan blades are causing noise, then turn off the power to the system and gently clean the blades to restore its smooth and quiet operation.
• Motor Issues: Worn-out motor bearings or old belts can produce very loud squealing and/or grinding noises. To troubleshoot, check the motor and inspect its belts and bearings. If the belt is worn or damaged, replace it. Or, if the motor’s bearings are shot, then you will need to replace the motor.

High Energy Bills

Another common trouble call is one in which a homeowner is concerned about receiving energy bills that are suddenly and significantly more expensive than usual. This is a common issue in cases where a system is older and no longer working as efficiently as it used to. However, it can also be caused by poorly maintained equipment, which can lead to higher energy consumption. In situations where a system is old, replacing it with a newer and more energy efficient model is the most logical choice. But if the system still has life in it, then providing maintenance on it and scheduling the system for routine servicing will help restore the system’s efficiency and delay a complete replacement for some time. 

Another potential cause of high energy bills can be related to the ductwork. For example, air loss in ducts forces the system to work harder. Inspect the ductwork and repair any leaks to help minimize air loss and improve efficiency. 

And then there are cases where a home’s excessively high energy bills are caused by simple user error. For example, the homeowner may be setting the thermostat too high or too low without understanding that doing so increases their energy use. In this situation, you can educate your customer about the most efficient way to use their thermostat and help them program a heating and cooling schedule that better fits their life and budget.

Frozen Evaporator Coils

In the summer, it’s not uncommon for some homeowners to find their evaporator coils covered over with ice and their air conditioning not working. There are a few different reasons why evaporator coils can become frozen, and these include:

• Restricted Airflow: A dirty air filter or blocked vents can restrict airflow to the point that it causes the coils to freeze. To troubleshoot this, first turn the power off to the system and let the coils thaw completely. Check the air filter and replace it if dirty. Inspect the vents and registers in the home to ensure that they are open and unobstructed.
• Low Refrigerant Levels: Insufficient refrigerant reduces heat absorption, and this will eventually lead to the coils freezing. To troubleshoot, use your gauges to check the refrigerant level and determine if there are any leaks. If leaks are found, fix them before recharging the refrigerant.
• Faulty Blower Fan: If the fan isn’t circulating air, then the coils can freeze. Inspect the blower motor to ensure that it is operating properly and that the fan blades are clean. 

Foul Odors Emanating From the System

A well maintained HVAC system does not produce foul odors, so when a homeowner calls in about bad odors wafting through their vents, there can be a few different causes based on the type of odor. For instance, if the system is producing a burning smell, then the culprit is usually an electrical or venting issue. There may be electrical components that are overheating and/or melting or if there is a crack in the furnace’s heat exchanger, then it could be causing flame rollout. Each of these are very dangerous and need to be fixed immediately. 

If the homeowner is complaining about a moldy or musty odor, then the cause will usually be either a blocked condensate drain line or there may be mold or mildew building up inside the ducts. To troubleshoot, check the condensate collection pan to see if there is any stagnant, standing water and if there is, make sure the drain is open by flushing it with a mixture of water and vinegar. If mold in the ducts is to blame, then the system will need to be cleaned and disinfected.

Troubleshoot Your Way to Success With BTrained’s HVAC Programs

Successfully troubleshooting HVAC problems like the ones listed above requires a combination of technical knowledge, diagnostic tools, and attention to detail. While some technicians are naturally adept at solving complex problems, most gradually build this important skill set through a combination of practical classroom education and intensive on the job training. 

At BTrained, our HVAC training programs provide students with an ideal starting off point as they work their way toward becoming experienced and in-demand HVAC techs. If you want to enter this highly rewarding field, then our HVAC training programs in Huntsville, AL are specially designed to help you gain the skills, confidence, and experience needed to succeed. Our class sizes are small, so you can enjoy personalized instruction and they’re designed to fit conveniently within your busy schedule.

At BTrained, you can expect to receive plenty of practical hands-on experience and valuable one-on-one attention from our team of highly skilled instructors. But due to the success of our students, this also means that our programs tend to fill up quickly. So, if you want to get the training you need to start on your path to becoming a skilled HVAC technician, then it’s recommended that you claim your spot early. Enroll today and secure your spot in one of our upcoming HVAC training courses in Huntsville, AL!