FieldBench
Procedures
Airflow5 min

Ice on the evaporator

Thaw first. Diagnose second. Charging a frozen coil guarantees a callback.

Thaw

  • Fan-only, indoor blower on, outdoor off. Catch melt water. Do not chip ice off aluminum.
  • A heat gun on a plastic drain pan is how you buy a new coil.

After it is wet and clear

  • Airflow: filter, wheel, coil, return size, blower speed.
  • Charge and superheat / subcooling on a stable run (10+ minutes).
  • Metering: piston size, TXV bulb strap and insulation, inlet screen.
  • Low load / short sessions (hotel, unused wing) can ice a correctly charged unit — runtime and airflow both matter.