HVAC Evaporator Coil: Function and Maintenance

Your HVAC evaporator coil plays a crucial role in cooling the air in your home. Liberty, MO, gets some high temperatures during the summer. So the last thing you want is for your evaporator coil to fail when you need it the most.

The Air Unlimited Heating & Cooling team is here to answer all your questions about evaporator coils. We will talk about their function and maintenance and why they are so important. We will also talk about tips for evaporator coil maintenance and cleaning.

What is an Evaporator Coil?

The evaporator coil is the part of your HVAC system that absorbs heat from the air before pumping it into your home. Evaporator coils and condenser coils are the two main components of your HVAC that facilitate heat transfer.

To understand how an evaporator coil works, it’s necessary to understand how an AC works. Unlike furnaces that directly produce heat, air conditioners remove heat from the air to cool it. Cold refrigerant coolant in your AC absorbs heat from the air, causing the liquid to expand into a gas.

Your AC then pumps this heated gas to the evaporator coils, which absorb the heat in the air. A fan blows this heated air through your AC vents and outside your home. The AC then pumps the coolant to the condenser coil to start the entire cycle again.

Types of Evaporator Coils

All evaporator coils operate on the same principle. The AC fan blows hot air over the coil, and the evaporated coolant extracts heat. The main differences between types of evaporator coils are the orientation and direction of the coil/airflow.

Vertical Coils

Vertical AC evaporator coils sit vertically while a fan blows air up or down over them. Coolant gas flows through the coils to maximize surface area and heat transference. After transferring heat, the coils channel condensed water into the drain pans.

Cased Evaporator Coils

Cased evaporator coils consist of a horizontal coil with a metal casing. Cased coils work the same as vertical coils but have a metal casing for protection and to help with heat dispersion. You can find both vertical and horizontal cased evaporator coils.

Uncased Evaporator Coils

Uncased coils are the same as cased coils, except they lack an outer casing. The lack of casing makes these kinds of evaporator coils easy to modify. You can customize the shape of the coil to fit the unit however you want.

Signs of a Bad Evaporator Coil

Below are some of the most common signs of a bad evaporator coil. If you notice any of these issues, schedule an inspection immediately.

Warm Airflow

Evaporator coils extract heat from air before cycling it through your house. The most obvious sign of a broken evaporator coil is an inability to blow cool air. Hot air is a major sign that something is wrong with the coil.

Refrigerant Leaks

Refrigerant leaks are another common sign of a broken evaporator coil. Cracks can cause excessive condensation, resulting in leaking coolant fluid. Leaking refrigerant fluid has a semi-sweet aroma that may increase when you turn the unit on. 

Excessive Frost

If you have a broken evaporator coil, your AC unit may form excessive frost. Evaporator coils disperse heat to the rest of the AC, keeping the interior component warm. If your evaporator coil can’t warm AC components, it may start to build up frost. Excessive frost impacts system performance and can damage your hardware.

Compressor Won’t Turn On

The compressor relies on specific pressure to know when to cycle on and off. If your evaporator coils are malfunctioning, then system pressure will be off. The result is your compressor won’t know when to turn on, so your AC won’t cycle properly. In some cases, low compressor pressure can cause your AC to cycle too frequently.

Variable AC Temperature

Lastly, inconsistent temperatures can be another sign of a bad evaporator coil. Sometimes the temperature might be excessively high, while other times, it might be too low. Damaged HVAC evaporator coils have variable performance, so they might periodically be unable to cool air evenly. 

Evaporator Coil Maintenance

No matter what kind of evaporator coil you have, you will need to perform regular maintenance to keep it in good condition. Since evaporator coils sit exposed to air, they can pick up dust and dirt. Debris can clog your coil, lowering its surface area and reducing its effectiveness.

Additionally, excessive dirt and dust can exacerbate crack and leak formation. Dirty AC coils experience high pressures that the materials cannot withstand. Heat and stress cause coils cracks, which lead to leaks and reduced system performance.

We recommend that you service your AC and coils at least once per year. Ideally, you should get AC maintenance twice per year—once at the beginning of the spring and again during the fall. Regular maintenance ensures your coils work effectively and can extend the lifespan of your system by up to five years. 

Evaporator Coil Replacement

In some cases, your AC technician might need to replace your evaporator coil. First, they will remove the broken coil after siphoning extra coolant fluid from the component. They will then solder a new coil onto the existing space. Next, they will replace the coolant fluid and test the new coil by running several cooling cycles.

Costs for evaporator coil replacement depend on your AC model and condition. Generally, you can expect to pay anywhere between $500 and $2,000 to replace a broken coil. Repairs may take a few days if your technician has to order replacement parts from a different source.

Evaporator coils have several high-voltage electrical connections. Shocks from AC units can cause serious injury and even death, so you should always call an expert before handling them. Leawood’s trusted air conditioning technicians can ensure replacement proceeds smoothly and safely.

How to Prevent Evaporator Coil Problems

No matter how well you take care of your AC system, you will eventually need professional repairs and service. In the meantime, however, here are some preventative tips to avoid evaporator coil problems.

  • Regularly change your AC filter. Dirt and debris can clog your coils, rendering them ineffective. Regularly replacing the air filter will prevent excessive dust buildup. We recommend changing air filters at least once per month. 
  • You can also lightly clean the coil yourself. Use a small amount of alkaline cleaning solution and a soft-bristle brush to remove surface dirt and grime. Make sure you shut off power to your AC unit before handling the coils and other components.
  • Get in the habit of checking your coolant levels. Low coolant levels increase heat and pressure in evaporator coils, increasing the risk of issues. You will only need coolant top-offs once every few years, but schedule maintenance immediately if you notice falling levels.
  • If you notice any air conditioner problems, schedule maintenance as quickly as possible. Even small issues can develop into costly repairs if you neglect them.

Contact an HVAC Expert Today!

Air Unlimited Heating and Cooling has been serving the Liberty area for over a decade and has helped countless homeowners maintain their comfort. We place great importance on customer satisfaction and will work tirelessly to meet your needs. If you experience any HVAC evaporator coil problems, make us your first choice!

If you would like to learn more about our HVAC repair and evaporator coil services, contact us online or give us a call today at (816) 286-7258! We look forward to hearing from you!

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