When the copper in your air conditioning system is covered in a layer of ice, it is called "freezing up." Heat pump systems build ice in the winter time when ran in heating mode; this is normal as long as the system eventually goes through a defrost cycle.When the system is running on cooling and is building ice, this can be a problem.
An air flow problem can cause an evaporator coil to freeze while the system is cooling your house. Some common causes of a system freezing up are :
- A dirty air filter, restricting airflow into your unit.
- A dirty coil, restricting airflow in a similar situation to a dirty filter.
- A collapsed duct.
- A problem with your evaporator motor, which controls the amount of airflow through your unit.
- Freezing up can also be caused by freon problems such as low refrigerant charge, or refrigerant flow problems.
If your system is freezing up, make sure you do not have a dirty filter. If you have a dirty filter, remove it and defrost your system. See the "How do I defrost my unit if it is frozen up?" FAQ. Freezing up is also damaging to your compressor over a period of time. It causes what is known as sludging, which is when liquid refrigerant washes the oil out of the compressor. This could permanently destroy the internal components of the compressor. If
a dirty filter is not the cause of your system freezing up, it is recommended that you have a service technician diagnose the cause of the freezing and make neccessary repairs.