How to Troubleshoot a Sub-Zero

Sub-Zero brand refrigeration units and appliances have been on the market since 1945. The brand is known for its high-end appliances and is often found in professional kitchens around the world. Even the most expensive products can have problems, however, and if you are experiencing difficulties with your Sub-Zero refrigerator, the process of troubleshooting may help determine or even fix what is wrong. Just perform a few basic checks and you may isolate the problem and be better able to deal with it.

Control Center Indicators

Sub-Zero refrigerators are finished in stainless steel for style and sanitation.

Step 1

Read your Sub-Zero Control Center display panel.  If the panel displays "Service" and there are no further instructions, call the Sub-Zero Customer Service Department at (800) 222-7820 for assistance.

Step 2

Look at your Sub-Zero Control Center display panel.  If the panel flashes "Service," the condenser may require basic cleaning.

Locate the stainless steel grille on the front of the appliance.  Remove the grille screws with a screwdriver and tilt the grille open.

If your grille has springs that are in the way, reach into the hinge and release them before sliding the grille off the unit completely.  Inside you will find a mesh filter similar to those in air conditioning units.

Use a vacuum with a soft brush attachment to gently clean off any dust or debris from the surface of the filter, as well as the condenser cabinet.  If you clean the condenser and the control center panel still flashes "Service," the heat sensor may be faulty.

Disconnect power to the appliance then plug it back in.  This should reset the sensor and alleviate the problem.

If the "Service" message continues to flash when you turn the machine back on, call customer service. 

Step 3

Read the Sub-Zero Control Center Display panel.  If the panel flashes both "Service" and "Ice," try powering off the unit then turn it back on and see if the panel is still flashing.

If it is, check near the ice maker for a water leak.  If a leak is present, there may be a problem with the ice maker solenoid valve.

Call customer service for assistance. 

Running/Not Running

Step 1

Check the household power supply if your Sub-Zero refrigeration unit stops running.  The circuit breakers may have tripped, or the plug may have come out of the outlet.

Check the control center to see if the unit was mistakenly turned off.  Check all drawers and doors to see if something is preventing one or more from closing.

If none of these checks turns up anything, wait 30 minutes then power off the machine.  Turn it back on and see if it begins running.

If it does, the fridge may have been in automatic defrost mode.  If it does not run, call customer service for assistance.

Step 2

Look to see if the space around the condenser is clear of dust and debris if your Sub-Zero unit seems to be running for too long.  If the filter is clear, check to see if any of the doors or drawers have been left open or if there is anything preventing the doors and drawers from closing fully.

If there is still no visible problem, the appliance may be running to compensate for hot or humid weather or an overfull storage space.  Note that other components of the appliance may also sound like the motor; for example, the ice maker, fan or circulation center may create noises that sound like a running motor.

Step 3

Listen carefully for other unusual sounds originating from your Sub-Zero.  If you hear a buzzing sound, the supply line to your ice maker may be disconnected or turned off.

A lack of ice can also indicate this problem.  Become familiar with the normal operational sounds of your machine to avoid mistaking them for potential problems.

Too Warm/Too Cold

Step 1

Check inside your Sub-Zero refrigeration unit to see if the temperature is warmer than usual.  If so, check that the control center settings are correct and within the normal range.

Next check the area around the condenser for dust or other obstructions which may be causing it to overheat or malfunction. 

Step 2

Verify that none of the doors or drawers is ajar.  If you have recently added a large amount of items to the fridge unit, the overall temperature of the interior may drop until these items are sufficiently chilled.

Step 3

Check for open drawers or doors if you are experiencing frosting or condensation inside your Sub-Zero.  These same causes may be behind any external condensation as well.

If there are no issues with the doors or drawers, call customer service for assistance. 

Things You Will Need

  • Screwdriver
  • Vacuum with soft brush attachment
  • Work gloves


  • If you smell a strange or unpleasant odor coming from your Sub Zero, try cleaning out the drain pan and the unit's drainpipe.
  • When cleaning the condenser, slide the vacuum brush only along the ridges of the filter and never across them. Crossing the ridges may result in damage to the soft metal coils.


  • Wear work gloves when cleaning the condenser filter. The stainless steel grille and condenser cabinet may have sharp edges.

About the Author

Robert Morello has an extensive travel, marketing and business background. He graduated with a Bachelor of Arts from Columbia University in 2002 and has worked in travel as a guide, corporate senior marketing and product manager and travel consultant/expert. Morello is a professional writer and adjunct professor of travel and tourism.

Photo Credits

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