Has your central air conditioner suddenly stopped putting out cold air? Check inside the air handler, which is typically inside your furnace, to see if the evaporator coils are iced over. This icing over is often referred to as the air conditioner "freezing up." Potential causes can vary depending on coexisting conditions, but if the unit seems to freeze up more often when the weather is humid, the problem could be in your refrigerant.
Refrigerant is the chemical fuel that powers the cooling system. The refrigerant starts as a gas but is changed back and forth between gas and liquid in a system of coils in both the outside condensing unit and the indoor air handler. A problem with the refrigerant can throw this system out of whack.
Low or Uncharged Refrigerant
The cooling system uses up a small amount of refrigerant every time a full cycle runs due to the phase changes. Eventually, your unit will start to run low on refrigerant. The system needs an adequate amount of refrigerant so that each phase change occurs correctly. An overly low amount of refrigerant can lead to the evaporator coils working too hard to convert a smaller amount of refrigerant and this causes the coils to freeze over.
Low refrigerant is an easy problem to fix since the HVAC technician simply needs to top off your existing supply. The refilling process is called charging due to the rather complicated gadgets and process involved in adding more refrigerant. The complicated process means you should absolutely leave this step to the professionals.
Did a new technician recently recharge your air conditioner – or did you attempt the process yourself with limited knowledge of how the charging process works? It is possible that the wrong type of refrigerant was added on top of the remaining refrigerant.
Adding the wrong refrigerant into your central air conditioning system will throw off the delicate chemical balance that carries the fuel through the system and correctly cools the evaporator coils. Your air conditioner will eventually stop working entirely, and leaving the wrong refrigerant in there long term can potentially damage your unit.
If you suspect the wrong refrigerant was used, call in a reputable air conditioning service to check the refrigerant and change out the chemical, if needed.
If your unit is freezing up and you have a newer unit or recently had a recharging that you know was done correctly, there could be a leak somewhere in the lines or coils. You can check for any signs of wetness in and around the condensing unit or air handler. Make sure the wetness isn't simply water produced during the cooling process. Or call in an HVAC tech to perform an evaluation and fix any leaks before you end up with overly low levels of refrigerant.