Ice on an air conditioner does not mean the system is cooling better. A frozen evaporator coil blocks airflow and prevents the system from absorbing heat properly.
The first step is to stop the freezing condition, allow the coil to thaw, and then determine why the coil temperature fell below freezing.
Restricted Airflow
A dirty filter, blocked return, dirty evaporator coil, blower problem, closed registers, or duct restriction can reduce the amount of warm indoor air passing over the coil. With insufficient heat load, the coil can drop below freezing.
Low Refrigerant
Low refrigerant mass flow can reduce evaporator pressure and saturation temperature. A low charge may be caused by leakage or an earlier charging problem. Refrigerant should be evaluated only after the coil has thawed and airflow has been checked.
Metering Device or Refrigerant Restriction
A restriction in the refrigerant circuit or a metering-device problem can also create abnormal evaporator conditions. Pressure and temperature measurements are needed to distinguish these conditions from a simple low-charge problem.
Blower or Control Problems
A failing blower motor, ECM module, control board, relay, or incorrect airflow setting can reduce indoor airflow. Intermittent airflow problems can be particularly difficult because the system may appear normal by the time service arrives.
What to Do When You See Ice
Turn cooling off and allow the coil to thaw. The indoor fan can sometimes be used to help thaw the coil if doing so will not create a water problem. Do not chip ice from the coil because the fins and refrigerant tubing are easily damaged.
Preventing Repeat Freezing
Maintain filters, keep return and supply paths open, correct blower or duct problems, keep coils clean, and repair refrigerant leaks or control problems. A coil that repeatedly freezes needs diagnosis rather than repeated thawing.
Need HVAC service in Allen?
Call A Plus Air or book your appointment online today.