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Common Air Conditioning Problems and How to Correct (and Prevent) Them

Have you ever spent a hot summer in the central Ohio area, in a home or business suffering from air conditioning issues? If you’re like us, it’s an experience you don’t want to repeat. If that’s the case, don’t leave your family’s summer comfort to random chance. Read about the most common air conditioning problems and how you can prevent them.

While there are a myriad of issues than can happen to an air conditioning system, these are the top problems that we see time and time again.


The refrigerant in an air conditioning system is the magic that makes it all happen! An air conditioner moves refrigerant in a gas form, from the outside condenser into the evaporator coil, where a fan blows air across the coil, sending cool air out into the home. The refrigerant warms up, converts back to a liquid, then travels back to the outside compressor to start the cycle over again. This is in a closed, pressurized system. If the refrigerant part of your AC system develops a leak, you can end up with less than the required amount of refrigerant in the system to cool the air.

SOLUTION. An EPA certified HVAC technician can diagnose the low refrigerant, repair the leak, and refill to optimal levels. Certification is an EPA mandate prior to allowing anyone to work on any refrigerant system.


The job of the evaporator coil (aka “A coil”) is to transfer the heat from your home into the compressed refrigerant, cooling the home. The coil needs warm air circulating across it for it to do its work. When something prevents enough warm air from blowing across the coil, warming it up, it gets too cold, and a layer of ice can build up on the outside of the coil. When that happens, you’ll have either warm air or no air coming from your registers.

SOLUTION: First, turn off your Air Conditioner to allow the coil to thaw, then contact a professional HVAC technician to troubleshoot, diagnose and resolve the problem prior to using the it again.


The outdoor unit on an air conditioner contains a condenser coil, which acts like a radiator to release the heat captured from inside the building. If the coil gets covered in dirt, grime, organic material like cottonwood seed, leaves or twigs, it can’t do its job very well or at all. This can be a common problem in a large city like Columbus, given all the soot and pollution in the air, and given the propensity for cottonwood trees to release its pollen into the air during the summer. When the condenser coil is very dirty, it can no longer transfer heat from inside the building and release it into the air, leading to increased system wear and tear, and possibly system failure.

SOLUTION: A thorough AC system tune-up and check out allows a trained HVAC technician to catch issues like dirty coils, clean the system, and offer tips to prevent the problem from returning. We recommend you have this service performed annually to get maximum life out of your home’s heating and cooling system


Forced-air furnaces contain a fan, spun by a blower motor, that forces air through the evaporator coil, sending cooled air out into the home. The outdoor unit also contains a motor-driven fan that forces air through the condenser coil to expel the heat transferred from inside the building. Either of those fans and their motors can fail for a number of reasons, including an electrical failure of the motor, insufficient lubrication of the motor, a buildup of dirt and debris, or worn belts. When these components fail, the result is poor (or no) airflow and no cold air blowing from the AC registers. Neglecting the problems when they’re small can lead to bigger problems later.

SOLUTION: You can visually inspect the outdoor unit to see and hear if the fan motor is turning. Inside the home, if you don’t feel air coming from the heat registers, listen around the furnace and listen for the fan motor running. If either of these units fail, you’ll have to seek help from a professional HVAC service technician to properly diagnose and fix the problem.


Any forced-air heating and cooling system uses ductwork that runs throughout the building to deliver warm or cool air, depending on the time of year. Breaks, or holes in the ductwork, can allow that cooled air to leak out inside the home’s walls where it does nobody any good. This can cause the air conditioner to work even harder to try to maintain the temperature set on the thermostat, resulting in premature failure of the whole system and driving energy bills higher.

SOLUTION: Ever heard of “duct tape?” Of course you have! It’s that extremely sticky, silver-backed tape. You can plug small holes and leaks with it, but be sure to find the source of whatever caused holes, it could potentially be rodents like mice or squirrels. Ductwork can sometimes sag or disassemble itself if not properly brace and attached. If that’s the case with your home, you can self-repair the issue, otherwise give us a call.


Older-style mercury switch dial thermostats can be incorrectly calibrated, resulting in the air conditioner not actually delivering air at the desired temperature. For example, you could have your thermostat set to 72 degrees, but the thermostat is giving instructions to the Air Conditioner to get the home’s temperature to 75 degrees.

SOLUTION: Frankly, for the fee to have an HVAC technician diagnose a thermostat issue and calibrate the old dial-style thermostat, you can get a modern, microprocessor controlled thermostat that you can program and control from your smartphone. If you still have one of those older units, you should definitely consider upgrading.


One result of the evaporator coil doing its job of transferring heat from the home into the refrigerant: condensation. That moisture is supposed to drain through a drain line, down into a pan, and down a drain. The line or drain can get clogged, allowing the pan to fill with water, which can back up into the AC system, causing damage. In addition, a clogged condensate line can leak water onto the surrounding area, causing additional damage and one heckuva mess to clean up. Over time, all that moisture can cause mold growth in that environment.

SOLUTION: Clear the condensate drain lines to ensure the moisture that forms on the coil is properly removed and going where it should, down the drain. Depending on your system, you can use common tools to clear the condensate drain.


So far, we’ve covered specific issues and how to resolve them. Now, we’ll look at home to prevent many of these issues in the first place.


This is one of the most common, and easiest to resolve, issues with a home’s air conditioning system. Replace the dirty filter with a filter that’s the right size (you can find the size on the previous filter) and the appropriate MERV rating for your needs. We recommend a pleated air filter that can capture more particles than the typical fiberglass filter sold at department stores.


If it seems like there isn’t quite enough air blowing from your registers, inspect your system for leaks. Qualified HVAC technicians have equipment to find leaks and skills to quickly seal them.


It’s kinda pointless to install a microprocessor controlled thermostat and not take full advantage of its features. Many newer thermostats connect to your home’s WiFi network, allowing you to control it remotely with an app on your smartphone. They also allow you to program them to match your family’s activity levels (i.e. turn the temperature higher when there’s nobody home), and some even have artificial intelligence that can adjust based on that activity.


We recommend three feat of clearance for your air conditioner’s outdoor unit so shrubbery, grass, twigs and dead leaves don’t interfere with its operation. Keep the organic material cut back so the system can run as efficiently as possible.


Considering all the electrical, mechanical and plumbing issues that could go wrong with your home’s HVAC system, we can stress strongly enough the value of having routine maintenance performed on your system. We recommend a spring tune-up and checkout for your AC system prior to using it for the year, and a fall furnace tune-up and safety check before the first real cold days. In the long run, you’ll save on repairs because a maintained system will run more efficiently. You’ll also save on energy costs, because a well-maintained system will run for efficiently.


About Dor-Mar Heating & Air Conditioning

In continuous operation since 1962, our expertise goes beyond just the mechanicals of your HVAC system. For top-notch service keeping your home’s heating and cooling system clean and your family breathing clean, filtered air, contact Dor-Mar today.

Our team offers a wide array of routine maintenance and emergency services for your heating and cooling system, allowing your family to breathe fresh, safe, clean air and be comfortable year-round. We also offer a number of add-ons to your HVAC equipment that can improve your home’s IAQ, such as electrostatic air filters, whole-house humidifiers, duct cleaning, Ultraviolet-C lighting systems, and more.

Schedule an appointment for HVAC system troubleshooting or maintenance with us today by using our online contact form, or call one of our seven neighborhood offices listed below. We pride ourselves on our customer-focused service, and our reviews show it.

NEWARK  740.345.6639 • COLUMBUS 614.238.6689 • DUBLIN 614.545.8939 • REYNOLDSBURG 614.365.1579 • WESTERVILLE 614.381.1540 • GROVE CITY 614.595.3098 • ZANESVILLE 740.454.2420

Dor-Mar…Your Climate Hero!

*Please note: neither the Centers for Disease Control(CDC), the World Health Organization (WHO), nor the manufacturer of our UV-C Devices have officially announced whether UV-C kills the current strain of Corona Virus (COVID-19). We urge you to err on the side of caution until we have a definitive answer, and take other measures to prevent the acquisition or spread of this virus.

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