HVACopedia

All brands · Air conditioner troubleshooting

Coil iced, airflow blocked, poor cooling, high box temp

What is going on

Possible causes and checks for: coil iced, airflow blocked, poor cooling, high box temp.

Likely causes

  • Defrost not initiating (timer motor dead
  • Wrong timer type/wiring)
  • Heater or hot-gas solenoid failed
  • Termination thermostat failed
  • Too few defrosts
  • Fins too tight for application
  • High TD

Check in this order

  1. Timer advance test
  2. Heater amps/continuity
  3. Solenoid coil
  4. Termination switch
  5. Defrost frequency/duration
  6. Compare wiring to timer type (time-time
  7. Time-temp
  8. Time-pressure)

More air conditioner guides

Related

Calculators and reference tables

Take it to the job

All guides, error codes and tips work offline in the HVACopedia app.

Open the app

Source: General HVAC service practice — verify per model. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.