Without coolant, your home's central air conditioner unit will be unable to lower the temperature. Although coolant problems aren't common, they do occur, so it's vital you know the symptoms and repair options available.
In a modern central air conditioning unit, the coolant is in a closed system. This means that the coolant recirculates for the life of the air conditioner unit, so there is no need to refill or replace it. Coolant is also sometimes called refrigerant or freon, although actual freon (R-22) is no longer in use. Instead, the preferred coolant today is R-410A.
The coolant lines are made of copper. One line loops from the outdoor unit to the indoor condenser, while the second line loops back from the condenser to the outdoor unit. The coolant circulates through these lines as it exchanges the heat out of the warm air so that it can be cooled and then blown throughout your home.
Although the system is supposed to be closed, leaks aren't an impossibility. Lines can become damaged over time, which may lead to a leak. Corrosion is rare, but not unheard of, or lines can become pinched or bent during renovations or similar.
The most obvious sign of a coolant leak is hot, humid air coming from the AC. It may struggle to cool the house as well as it used to, or it may fail completely. Often, the cycles will run longer as the unit struggles to cool, which can also lead to increased electric bills. In the early stages of the leak, you may sometimes hear a bubbling or hissing noise from the lines as the coolant escapes. There may also be ice formation on the lines due to poor thermal exchange from a lack of coolant.
If you have an older AC unit that uses R-22 Freon, then repair isn't recommended. This coolant is no longer available due to environmental concerns, so you will need to replace your air conditioner. Your tech may also recommend that you replace the unit if it is reaching the end of its expected service life.
For newer units that should have many years of service left, it is possible to replace the damaged lines successfully. After replacement, the system will be recharged. This means that it is refilled with new coolant.
For more information about air conditioning repair, contact a local HVAC company.