You may never have heard about capacitors and “evap coils”, and yet, you use them every day. That’s right: your HVAC system is built around these components. Without these, it can’t function. In our 40-year operating as an air conditioning company in West Berlin, NJ we can say that as soon as your AC is not blowing cold air, you can suspect that these components and a couple others have technical issues and don’t function properly.
Let’s first describe the issues on a general level. Then we’ll go in the details, and explain what the HVAC technician does to identify them and remedy them.
Capacitor Issues
Capacitors store and release electrical energy. The role of tose used in an AC unit is to start the compressor and the fan motors. Over time, capacitors lose their charge capacity. This is the normal wear-and-tear process of an electronic component constantly exposed to weather and temperature variations, as well as to power fluctuations. With a failing “start capacitor”, the compressor struggles to start. When the “run capacitor” fails, the AC unit motor operates inefficiently, which increases energy consumption and overstrains the motor.
Evaporator and Condenser Coil Problems
The evaporator and condenser coils play a critical role in heat exchange. How does this happen? Typically, dirt and debris accumulate on the coils. This accumulation insulates the coils, and reduces their efficiency in absorbing and releasing heat. In turn, this forces the compressor to run longer (to reach the target temperature), accelerating wear-and-tear. In the evaporator coil, poor airflow or low refrigerant levels routinely the coil to freeze, further impeding heat absorption. At the refrigerant level, corrosion due to environmental factors creates leaks and down the road, system failure.
The role of maintenance carried out by your air conditioning company
An HVAC technician who conducts a routine maintenance call will follow specific procedures to check and maintain the compressor. These involve specific checks and measurements of the health of the capacitors, as well as a visual inspection and measurement of how efficiently the evaporator and condenser coil work.
Checking and Maintaining Capacitors
- Visual Inspection: On a typical air conditioning repair call, our technician begins by inspecting visually the capacitor for any signs of damage: bulging, leaking, rust. These are telltale signs that a capacitor probably needs to be replaced.
- Discharging the Capacitor: This is regular safety procedure. A capacitor stores and releases a large quantity of energy that can really shock a person if handled inappropriately. Our technician therefore discharges the capacitor fully before doing any testing. To do this, the technician places an insulated screwdriver across the capacitor leads: this releases any stored energy.
- Testing Capacitor Functionality: Using a multi-meter set to “capacitance”, our technician tests the capacitor by measuring its microfarad (µF) rating, and comparing it to the rating specified on the capacitor itself. The measurements usually deviate a little from factory specifications, but a significant deviation indicates that the capacitor requires replacement.
- Replacement authorization: Though a capacitor is not extremely costly, the air conditioning repair company must require the homeowners’ approval before changing the component. The customers must be informed in real time of the costs incurred in repairing their AC.
- Reconnecting and Testing: After replacing the capacitor, our technician reconnects it, making sure all connections are secure. Connections can become loose due to the weather-related expansion and contraction of the metal; so when replacing a capacitor, it is necessary to tighten connections. The technicians will then tested the system to confirm that the compressor and fan motors start and run correctly.
Checking and Maintaining Evaporator and Condenser Coils
As noted above, the typical sign that the coils of an air conditioning unit have an issue is when the unit struggles to blow cold air and has to run longer than usual to reach the desired temperature. Evap coils are durable but their fins are fragile and can be damaged by a physical shock. However, most of the issues we find are related to dirt and debris.
How do our technicians fix under-performing coils
- Inspecting Coils: When inspecting the evaporator and condenser coils, our technician checks for signs of dirt buildup, corrosion, or direct damage. We pay special attention to any areas that show signs of refrigerant leaks.
- Cleaning Coils: If the coils are dirty, we clean them using a specialized cleaning solution and a soft brush or low-pressure sprayer. We can’t use pressure washer because the fins on the coils can easily bend. For the condenser coil, we also clear the debris around the unit (leaves, dirt, brush). This is to maintain proper airflow.
- Straightening Coil Fins: Bent fins on the coils impede normal airflow and reduce system efficiency. Our technicians have a “fin comb” that enables them to straighten any bent fins gently.
- Checking Refrigerant Levels: After servicing the coils, our technician checks the refrigerant levels. Low refrigerant levels typically indicate a leak. This has to be fixed immediately, as leaks cause the evaporator coil to freeze and the compressor to overheat.
- Leak Testing: If our technician suspect there is a refrigerant leak in your system, the next task is to perform a leak test. We can use several methods for this: an electronic leak detector, soap bubble solution, and UV dye test.
- Repairing Leaks, Recharging Refrigerant: Tracing a leak is a meticulous process as we need to inspect the pipes and all the connections around the AC. When we find the leak, we repair it by soldering or replacing a section of the coil, or sometimes by applying a special paste that will plug the hole. Once the leak is fixed, our technician vacuums the system to remove air and moisture and to verify the leak is fully fixed. Then we recharge the refrigerant to specifications.
The last step is a system performance check. We run the AC to make sure it reaches and maintains the desired temperature, which will confirm that the evaporator and condenser coils are functioning efficiently.
A Systematic Process
HVAC is both a complex and a simple domain of knowledge. The technology that cools off and heats up your home has become very sophisticated and much more energy-efficient than it was in the past. But its fundamental principles remain simple.
When there is an issue with a system, there are usually just a few failure areas that need to be examined. The key is to proceed meticulously, based on well-known protocols. In this article, we discuss two of them. We will publish more of these to continue educating homeowners about their HVAC and what they should pay attention to.
About the Author
Filan & Conner is an air conditioning company located in West Berlin, NJ. We have been operating for 40 years in our area, and have gathered good ratings from our clients because our NATE-certified HVAC technicians know what they are doing and are continuously trained on new technologies.