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All brands · Air conditioner troubleshooting

Needs refrigerant (symptoms)

What is going on

Possible causes and checks for: needs refrigerant (symptoms).

Likely causes

  • Partially frosted evaporator
  • Low head pressure
  • Low suction pressure
  • Oil spots (visible leak)
  • Short cycling

Check in this order

  1. Find & repair leak, then charge to normal superheat/subcooling/pressures

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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.