Why do AC coils freeze?
Low air flow prevents heat from being absorbed by the refrigerant in your evaporator coil. The temperature in the coil then plummets below freezing and ice accumulates. A dirty filter, malfunctioning fan or motor are possible causes of low air flow. Restrictions of any kind in your ductwork can also prevent the air from flowing across the coil.
A faulty thermostat can overwork your air conditioner, reducing the temperature in the coil to the point of freezing it. The unit’s internal controls can also cause problems so have the entire control system checked.
Low refrigerant pressure results in a lower temperature in the evaporator coil as the refrigerant expands. This is typically caused by leaking refrigerant which must be repaired immediately.
How to prevent frozen coils
Clean and replace filters at least four times per year to maintain airflow across the coil. If you have pets or live in a dusty area, you’ll have to change them more often.
Keep your blower fan and motor well-maintained to ensure that it blows enough air across the coil.
Check your thermostat and controls so the unit operates within its designed temperature range while maintaining your indoor temperature at a comfortable level.
Have a professional recharge your refrigerant if the levels get too low. Checking refrigerant pressure should be part of routine maintenance.
Keep your evaporator coil clean to allow sufficient heat transfer from the air to the refrigerant flowing through the coil. This keeps the unit operating at a higher efficiency, lowering the risk for frozen coils as well as reducing your utility bills.
If you have a frozen coil and manage to melt the ice, the problem will remain unless you address the root cause. If your unit is properly maintained, the chance of it happening drops considerably. If you need help with a frozen coil or want to ensure it doesn’t happen to you, give us a call.