HVACopedia

All brands · Air conditioner troubleshooting

Won't start / no cooling

What is going on

Possible causes and checks for: won't start / no cooling.

Likely causes

  • No power, thermostat failed open, relay, capacitors (start/run/fan), electrical or thermal overload, open/shorted/grounded compressor windings

Check in this order

  1. Test for power, then stat, relay, caps, overloads
  2. Ohm windings with meter
  3. Only then go internal. p.842–843 [816–817]

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.