Essential Steps For Troubleshooting Your Sub-Zero Refrigerator

Fred's Appliance Academy
January 12, 2021

Sub-Zero is one of America’s most famous refrigerator brands, thanks to its legendary quality and appliance features. 

However, units sometimes require fixes. 

In this guide, we cover common troubleshooting and refrigerator repair procedures and methods. This guide applies to the following models: 

  • Model 700TR
  • Model 736TR
  • Model 700TF(I)
  • Model 736TFI
  • Model 700TC(I)
  • Model 736TCI
  • Model 700BR
  • Model 700BF(I)
  • Model 700BC(I)

Sub-Zero makes refrigerators with minimal maintenance requirements and efficient operation. However, integrated units can sometimes malfunction, indicate errors, or fail to perform as you hoped. 

If you have noticed a problem with your unit, check out the following common issues. 

Refrigerator Or Freezer Unit Has Frosted Up

After some time, you may notice that your Sub-Zero refrigerator has frosted up around the cooling element. This is a problem because it can adversely affect cooling performance and puts more pressure on the motor. It also takes up space in your appliance’s internals, leaving less space for food storage. 

Here’s the fix: 

  1. Ask yourself if you or somebody in your household accidentally left the door open. Leaving the door open allows moisture into the appliance which then condenses on the refrigerant at the rear of the unit where it eventually freezes. 
  2. Check the seals around the door. If they are damaged, moldy, or missing, then air can freely circulate into the refrigerator, allowing moisture to condense and form ice deposits. You can order a replacement gasket (door seal) from Sub-Zero. Heavy use causes gaskets to last a shorter length of time. The brand supplies the following gasket types: 
    1. BI – for Classic Series door replacement
    2. IT, IC – for Designer Series and Designer Wine Storage replacement
    3. PRO3650 and PRO4850 – for door gasket replacement. 
  3. You can also order generic refrigerator doors if you are unable to source OEM parts and fit them yourself. 

Refrigerator Not Operating

Occasionally, Sub-Zero refrigerators will stop working entirely. Don’t assume the unit has come to the end of its useful life. Simple fixes can often resolve the problem. 

Do the following: 

  1. Check that the power to the unit is on. If you have a separate circuit for your appliances in your home, check that you haven’t tripped the switch in your fuse box. Also, ensure that any buttons on the unit are set to the on or “1” position.
  2. Check that the refrigerator control is on. Sub-Zero refrigerators come with a thermostat that continuously senses the internal temperature of the appliance and adjusts cooling power accordingly. Sometimes, however, it fails to switch the compressor on, even when the fridge interior gets warm, making it seem as if the appliance is not operating. Try installing a new Sub-Zero thermostat. On refrigerators, the control is on the top right of the back wall. 
  3. Check that the unit is not in showroom mode. If you believe that it might be, contact Sub-Zero customer service for step-by-step instructions on how to convert it to normal mode. 
  4. Check that the unit is not in defrost mode. Sub-Zero refrigerators will periodically shut off the cooling unit to allow for de-icing. Wait for half an hour to see if the unit restarts. 

Ice Maker Not Working

Check the following: 

  1. The ice maker is turned on at the control panel. 
  2. The ice maker is connected to your water supply and operating properly. 
  3. The ice container is in the correct position in the freezer drawer. 

“SERVICE” Warning Is Flashing On The Control Panel Display

Sub-Zero refrigerators come with sensors that tell you when you need to service them. 

  1. When “SERVICE” flashes, it could mean you need to clean the condenser – the part of the refrigerator that transfers heat from the refrigerant to the air. Begin by switching the unit off and then switch it back on again. If the error message persists, you’ll need to call a Sub-Zero-accredited engineer to solve the problem. This is not a DIY fix. 
  2. On fridge-freezer units, you might see the error code “SERVICE” and “ICE” flashing. Try the above method and restart the appliance to see if the message goes away. If it doesn’t contact your Sub-Zero-accredited engineer. 

The Refrigerator Is Running Warmer Than Usual

Occasionally, you’ll notice that your Sub-Zero refrigerator is running warmer than usual, even if you have the cooling cranked up to max. 

Here’s the fix: 

  1. Ensure that the control is set properly. You may have accidentally set it too warm. 
  2. Check the condenser area is clean. If it isn’t, then you can try unplugging the unit from the wall and cleaning away any dust with a duster. If the problem is inside the unit itself, then you can get an accredited Sub-Zero engineer to fix the problem. 
  3. Think about whether you added a large amount of food recently. Solids tend to retain their heat longer than gases and require more energy to cool. If you just loaded your refrigerator with fresh shopping or a piping hot pie, that will raise the temperature, giving the impression your unit is running hot. If you’re worried, wait until the next morning and then check the temperature again to see if it remains elevated. 
  4. Check to see if the doors or drawers have been open for a long time. Refrigerators are powerful enough to cool their interior cavities, but they cannot cool your entire home. Make sure that nothing is obstructing openings and preventing them from closing. 

Your Refrigerator Runs For Longer Than Usual 

Sub-Zero refrigerators should run only when the temperature rises above the level you set. The rest of the time, they rely on insulation to keep your food chilled. 

Sometimes, though, you may notice that your refrigerator continues running for long periods, which can be a little disconcerting. 

Here’s the fix: 

  1. Consider the weather. On hot days, the refrigerator will run for longer to maintain cooler internal temperatures. 
  2. Ensure that nothing is obstructing the doors or drawers
  3. Check that the condenser area is clean. 

Light Bulb Requires Replacement

The lightbulb could fail in either the drawer or top compartment. And when this happens, you can’t see your food as clearly. 

Here’s the fix: 

  1. Replace top compartment light with a standard 40-watt bulb – code 3030030
  2. Replace the drawer compartment light with a standard 25-watt bulb – code 3030060. 
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