When the refrigerant is low, the temperature of the refrigerant at the beginning of the evaporator coils will be colder than the freezing point of water (less than 32°F). Because the coils are so cold, the condensation that forms on the coils will freeze.

What causes suction line to freeze?

Frost on a suction line may indicate a flooded evaporator. A flooding evaporator is being fed more refrigerant than it can boil off and this may slug the compressor. Liquid leaving the evaporator may be indicated by frost on the suction line or compressor.

Why does low refrigerant cause freeze up?

Low refrigerant or Freon®.
Another thing that causes an air conditioner to freeze is low refrigerant or Freon. This causes a drop in pressure inside the evaporator coil, which then allows moisture in the air to accumulate and freeze on the coil. A leak is typically responsible for low refrigerant.

What causes an evaporator core to freeze?

The most common reason for frozen evaporator coils is insufficient airflow. This is commonly caused by a clogged or dirty air filter, backed-up drain clogs, low fan speed, or a dirty evaporator coil. Check to see how many registers are closed in your home.

Does low refrigerant freeze coil?

Low Refrigerant
Improper refrigerant fluid levels can also cause an HVAC unit to freeze up. When the refrigerant is low, the coils will be too cold, causing them to freeze.

What is the reason for frosting on suction line down to compressor inlet?

Frost forms because the surface temperature of the refrigeration equipment has reached 32°F. In many cases, the compressor, suction line, or a component in the suction line will be below freezing temperatures and will have frost accumulation while still operating normally.

Can low refrigerant cause AC compressor to not turn on?

Yes, when the refrigerant level drops below the recommended level, AC Compressor may refuse to start. But do not panic because a faulty compressor does not mean the HVAC unit is compromised.