Patching an Old HVAC System
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Patching an Old HVAC System

When I married my husband ten years ago, I reluctantly agreed to move into the older brick home he already owned. I knew the house was outdated. Unfortunately, I didn’t have any experience renovating an older place. Immediately, I noticed the old central air conditioning unit in the home. After thoroughly inspecting the equipment, I was afraid the ancient unit wouldn’t make it through my first summer in my new place. Thankfully, I was wrong. After ten years, this same air conditioning system is still running smoothly. However, it has received some diligent care from a reputable HVAC contractor over the years. On this blog, you will discover the ways an HVAC contractor can restore an older air conditioning unit.


Patching an Old HVAC System

What Are AC Evaporator Coils, What Do They Do, And How Can They Break?

Mary Gonzalez

Your central air conditioner has an interior half located in the air handler that is either a standalone unit or housed within your furnace. The air handler contains a set of evaporator coils that play a vital role in the cooling process and actually provide the source of the cold air. Problems with the evaporator coils can leave you with inefficient cooling or warm air coming out of your vents.

So what are air conditioning evaporator coils, what do they do, and how can problems with the coils impact your entire system?

Evaporator Coil Function

The cooling process starts in the condensing unit outside the house where a set of condenser coils convert a gas refrigerant to a liquid so that the refrigerant can travel through supply lines to your air handler and the evaporator coils. The evaporator coils transform that gas back into a liquid, which causes the surfaces of the coils to chill. A fan circulates ambient air across the coils, which cool the air, and then the fan blows the cooled air out your vents.

The evaporator coils push the converted gas back outside and into the condensing unit, where the refrigerant can again start the whole route through the cooling system.

Potential Problem: Dirty Coils Lose Efficiency

The evaporator coils produce condensate when the coils become cold. The wetness makes it easy for dirt to adhere to the coils. Thickening dirt buildup can start to interfere with the calibration that allows the phase change to happen properly. If the phase change starts to suffer, your system's efficiency will go with it.

You can clean the coils easily using a no-rinse foaming cleanser you can find at any hardware store. Make sure you turn off the power at the breaker first and follow the package directions on the cleaner. You don't need to rinse the cleaner because the excess will drip into the drain pan at the bottom of the air handler and the cleaner still stuck to the coils will evaporate once you turn the unit back on.

Potential Problem: Frozen Coils Lose Efficiency, Flood Drain Pan

Loss of cooling efficiency can also occur if the evaporator coils get too cold during the conversion process, which will cause the surface of the coils to temporarily freeze. The freeze will prevent further rounds of refrigerant from converting properly and will ultimately cause a loss of efficiency even though the coils are initially colder, which seems like a positive thing.

The freezing coils can also produce excess levels of condensate that can overwhelm the drain pain, which is linked to a drain pipe to prevent the pan from overfilling. If the drain pan does start overfilling unexpectedly, the frozen coils might be the problem.

Call in an air conditioning contractor to examine the frozen coils because the problem is usually with the level or type of refrigerant in the system. And only a certified technician can work with the controlled chemical.