The most common A/C problem reported by customers is a frozen indoor coil. There are many different factors that cause the evaporator coil installed above your furnace to freeze. The coil freezes because the refrigerant travelling inside of it is at or below freezing temperature. As air is blown over the coil the natural moisture in the air will hit the coil and freeze to it. When everything is working properly this build up is very slow and when the thermostat is satisfied the frost has time to melt and go down the installed drain line. Sometimes the system is unable to reach the desired temperature and continues to build more and more frost until the entire coil is covered in ice. Before you call in an HVAC Tech for a service call, following these 6 simple steps could save you a lot of time, money and literal sweat.
1. Turn your A/C unit off. First things first. If you notice frost build up, or if you have very reduced airflow coming out of the vents around your house, turn off your A/C. Best practice is to turn the A/C option on your thermostat to OFF, but turn the fan only mode to ON. If your system is frozen up this will allow warm inside air to travel over the evaporator coil and allow it to thaw.
2. Check your furnace filter. If your furnace filter is starting to get plugged up it will drastically reduce the airflow across the indoor coil. This will cause the refrigerant temperature to drop much lower than it should causing frost to build up very quickly. Change your filter, give the system a few hours to thaw and restart the system.
3. Check your furnace fan operation. If your furnace fan does not start up, or does not run at full speed during cooling a freeze up will occur. Make sure your furnace fan is running when the system is calling for cooling. If it's not, trun off the system and call an HVAC Technician.
4. Check the evaporator coil drain line. If your furnace fan does not start up, or does not run at full speed during cooling a freeze up will occur. Make sure your furnace fan is running when the system is calling for cooling. If it's not, turn off the system and call an HVAC Technician.
5. Clear and open all vents in your home. Generally speaking your system is designed with the number of vents, size of the furnace and size of the ductwork installed in mind. If some of the supply air vents in your home are blocked or closed the airflow traveling over the indoor coil is reduced. this will give the same effect as a dirty filter causing a freeze up. Keep the air moving and open and clear all vents in your home.
6. Clean around the outdoor unit. If the outdoor unit has clutter or debris touching it can cause the system to run at higher than normal temperatures and pressures. The system may not be able to keep up with the cooling demand and eventually freeze up. Clear any and all debris from around the outdoor unit. Inspect the cleanliness of the outdoor unit it's self. If the unit is dusty or dirty shut off the power and use the wide angle spray of a garden hose to clean it.
If you've tried these tips and your system is still freezing up,