The coolant in your home's AC circulates in a closed system, so if you are low on coolant, it means that there is a leak somewhere in the coolant lines. Diagnosing and repairing the problem promptly will ensure your AC keeps functioning.
One of the most common causes of a coolant leak, particularly on a newer AC unit, is vibration. Vibration can cause damage to coolant lines, especially at joints and weld points. Repair means fixing both the leak and the cause of vibration. An AC vibrates from the movement of the fan and motor. It should be seated on anti-vibration pads to reduce movement. Proper leveling and maintenance will also reduce vibration.
Most coolant lines are made of copper. Although copper is resistant to corrosion, it is not immune to it. Over time the condensation that naturally occurs on the coolant lines can cause corrosion, which in turn results in small pinhole leaks. You may even be able to hear a hissing sound as coolant leaks slowly through these small holes. Replacing the lines is the most effective repair.
3. Joint Failure
There are one or more line joints and weld points on the copper coolant lines. These are typically the weakest point of the line, so often, any type of leak occurs here. Your repair tech will inspect the joints and welds for possible failure. Much like a pinhole leak, leaks due to joint failure tend to occur slowly, so you may not notice the refrigerant leaking, but you may hear it hissing out. Sometimes the weld can be repaired, while in other cases, full replacement of the coolant lines is a better repair option.
Coolant leaks can be a normal side effect of an aging AC. Eventually, the lines may fail completely, developing breaks or large holes and gaps in the tubing. When this occurs, the coolant will typically leak out quickly, and you may even spot the residue before the coolant evaporates away. Coolant leaks due to AC aging can sometimes be repaired with new coolant lines, but often it is just one of many symptoms that indicates that the AC is reaching its end of life. A full AC replacement may be the best option.
Coolant leaks should never be ignored. Not only will your AC function poorly if it is low on coolant, leaking coolant can also pose an environmental hazard. Contact an AC repair service immediately if you suspect a coolant leak.