Should you hear your fridge running all the time?

You should not hear your fridge running all the time continuously without cycling off, as a properly functioning refrigerator should cycle on and off with a duty cycle of about 40 to 60 percent. A normal refrigerator runs for 30 to 50 minutes, then shuts off for 20 to 30 minutes as thermostat is satisfied, so you should hear humming from compressor and fans for periods, then quiet periods. You should hear low humming from compressor at bottom, gentle whooshing from evaporator fan inside freezer, and occasional clicking from defrost timer or ice maker. If you hear your fridge running constantly non-stop 24 hours, it indicates a problem: dirty condenser coils causing compressor to overheat and run continuously trying to cool, door gasket failure or door left ajar letting warm air in, thermostat set too cold below 34 degrees, low refrigerant from sealed system leak, defrost system failure where frost blocks coils and fridge never reaches set temperature, or failing compressor that cannot reach pressure. Running constantly wastes energy and can burn out compressor. If fridge runs constantly, check door seals with dollar bill test, clean coils, ensure temperature set to 37F fridge and 0F freezer, and ensure vents not blocked by food. If it still runs continuously for over 12 hours with doors closed, call service as sealed system or control board may be failing.