If there’s one thing Sub-Zero refrigerators are good at, it’s keeping food cold. But there are many reasons your fridge is not cold enough. Your first thought may be that a vital component has malfunctioned. While this is possible, other reasons are more common and can often be resolved without a technician. Let’s look at why your Sub-Zero refrigerator is not cold enough.

The Temperature Is Set Too High

When your fridge isn’t cold enough, the reason can be as simple as an incorrect temperature setting. The refrigerator should be set to 38℉ and the freezer to 0℉. On 200, 300, and 500 Series Sub-Zero models, the dial controls should be set between 4 and 6 (10 is the coldest setting). Wait up to 24 hours after adjusting the setting to allow the fridge to reach the desired temperature.

The Refrigerator Door Isn’t Fully Closed

Warm air will enter and cold air may escape if the refrigerator door is left open or not closed all the way. Some models sound an alarm if the door is ajar. Closing the door should keep cold air in. If not, the rubber gasket may not be providing a tight seal because it’s dirty, loose, or damaged. A dirty gasket can be cleaned with a damp cloth, but a damaged seal must be replaced by a professional.

The Refrigerator Coils Are Dirty

Refrigerators have coils that circulate refrigerant to create cool air. Coils coated in dust or dirt won’t cool the refrigerant enough. Dirty coils also increase the risk of damage. Fortunately, you can and should clean the coils once or twice a year. They’re usually behind the grille at the top of the unit. Remove debris with an appliance brush and a narrow hose vacuum attachment. Reinstall the grille and your Sub-Zero refrigerator should now get cold enough.

The Appliance Lacks Power

Another place to look is the power supply. Start with the plug and check whether it’s pushed into the outlet. Insert the plug if it’s not or check that the outlet is powered. If the refrigerator isn’t turned on, check the circuit breaker and reset it if necessary. Also, verify the unit is plugged into a regular receptacle. Using a ground fault receptacle for a fridge is not recommended.

The Refrigerator Has a Faulty Component

A Sub-Zero refrigerator is dependable but has many components. Over time, these can wear out and prevent the unit from cooling to the right temperature. These are some of the parts that can malfunction:

  • Condenser Fan Motor: Removing obstructions from the fan blade can fix the problem. If the blade won’t spin freely after doing so, or continuity is an issue, the fan motor must be replaced.
  • Evaporator Fan Motor: A malfunctioning evaporator fan motor will prevent cold air from circulating. The freezer may get cold while the fridge stays warm. A stuck blade, excessive noise, and no continuity when testing the motor windings with a multimeter are reasons to replace the motor.
  • Start Relay: A failed start relay can cause the compressor to stop running or run intermittently. The relay can burn out or have a continuity issue. In both these cases, it should be replaced.
  • Start Capacitor: A faulty capacitor can prevent the compressor from starting, in turn preventing the refrigerator from getting cool. 
  • Temperature Control Thermostat: If the thermostat isn’t working, it won’t allow voltage to reach the compressor and fan motors. Adjust the thermostat and listen for a click. If you don’t hear one, test its continuity to determine whether replacement is necessary.
  • Temperature Control Board: The control board supplies the compressor and fan motors with voltage. If it isn’t working, the cooling system won’t receive the power it needs. 
  • Defrost Heater: The defrost heater assembly melts accumulated frost on the evaporator coils. If it’s not working, the coils will ice over and prevent the unit from cooling. The defrost thermostat may be defective as well.
  • Thermistor: Designed to monitor the refrigerator’s temperature, the thermistor relays this information to the control board. If it’s defective, the compressor and evaporator fan may not receive the signal to turn on.
  • Main Control Board: It’s rare for the control board to go bad, but if all other components check out okay, consider having a professional replace it.
  • Compressor: The compressor pumps refrigerant through the coils, so the fridge won’t get cool if it isn’t working. However, this is rare, but compressor replacement requires the skills of a licensed technician.

Contact Wilshire Refrigeration & Appliance

Customers in Southern California and Las Vegas depend on Wilshire Refrigeration & Appliance for factory-certified Sub-Zero refrigerator repair. If your Sub-Zero fridge isn’t getting cool, contact us and our licensed technicians will evaluate, diagnose, and repair the unit. Factory-specified replacement parts are stocked on our trucks to provide quick solutions. To request service, contact us online or call us!