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Air Conditioner: Coil iced, airflow blocked, poor cooling, high box temp

Updated · by Aurora Star Tech Inc.

Coil iced, airflow blocked, poor cooling, high box temp on a air conditioner: Possible causes and checks for: coil iced, airflow blocked, poor cooling, high box temp.

Homeowner with a air conditioner problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Common causes of coil iced, airflow blocked, poor cooling, high box temp

  • 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

How to fix coil iced, airflow blocked, poor cooling, high box temp: step by step

  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)
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

If the unit shows an error code, look it up: Carrier Air Conditioner codes Goodman Air Conditioner codes KeepRite Air Conditioner codes Lennox Air Conditioner codes Trane Air Conditioner codes

Source: General HVAC service practice — verify per model. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977