Jul 132013

Sub Zero refrigerators have several common issues. If your refrigerator is not cooling, there are a few things you need to check. Most new refrigerators use electronics and thermistors to regulate the temperature inside the freezer and refrigerator. On the majority of Sub Zero refrigerators there is a small control behind the dial that regulates the temperature. This control is known as a cold control. It’s what sends power to the compressor to get the freon flowing to the evaporator.

If you set the temperature using electronics on the display board, then your Sub Zero model uses a thermistor to regulate the temp.  For this article I want to explain why and how a bad cold control will cause a no cool issue with the freezer or refrigerator. If you have the electronic model and need help diagnosing your refrigerator, use the Free Repair Forum for technical help.

The first thing you want to check and see in a no cool event is the compressor. Is the compressor running. Is the compressor hot/warm? If the compressor is cold to the touch, then you likely have a cold control problem. The compressor on these refrigerators are hot. Given they are sealed wither on the top or bottom of the unit a lot of heat builds up inside the cavity. If the compressor is not hot then you need to figure out if the compressor is getting power. A volt meter is needed to verify this. If no power is present at the overload relay, you need to check the cold control.

So we’ve determined that the compressor is cold and is not getting power to the overload. The next thing we need to do is to take the inside apart to gain access to the cold control. Remove the plastic light housing in the top of the unit. You may need to remove the upper most shelf to get the housing out of the refrigerator. Once out you will need to remove the screws that hold the cover over the evaporator fan motor. Once the cover is off you will notice three small screws. Once the three small screws are removed, the back panel inside the refrigerator will come out enough so the cold control can be tested.

Now we have the back panel out and have access to the cold control. The next step would be to ohm or make a continuity check of the cold control. With the volt meter set it to the continuity setting or ohm’s setting. Remove at least one wire off the cold control. That way you don’t get a false reading. With the dial on the cold control set to the middle check the two prongs on the cold control. You should hear a beep or see a ohm’s reading on the meter. If the meter reads open line or does not show continuity, then you have a faulty cold control.

As you can see the wire coming off the cold control goes down and sits against the black evaporator behind the back panel. When the freon is pumped to the evaporator it boils. When freon boils it creates frost. The heat is absorbing the heat inside the refrigerator back into the refrigeration system and dissipating it at the condenser. That’s why you always hear people say keep your condenser coils clean. The heat transfer for the refrigeration system happens their.

So now you’ve figured out why your Sub Zero refrigerator is not cooling. You next step is to check with your local appliance parts supplier and see if the have the part in stock.

If you require assistance after reading this Sub Zero Refrigerator not cooling article, please sign up at our free repair forum and a Factory trained Sub Zero repair specialist will assist you in your refrigerator troubleshooting.

Sub Zero Refrigerator Not Cooling Repair Forum

Feb 222011

Sub Zero refrigerators are very common in our service area. Fixing a Sub Zero yourself is fairly simple with the proper guidance. Sub Zero uses a cold control to start and stop the refrigerators compressor. When this cold control fails the compressor will not start, creating a no cool situation in the freezer or the refrigerator section of a Sub Zero refrigerator.

To diagnose this issue a volt or ohm meter will be needed, a resistance check of the cold controls terminals will need to be made determining if the control has failed. There are two separate cold controls since two compressors are used on Sub Zero refrigerators. In this article we are going to access and test the refrigerator side of the built in.

To gain access to the cold control on bottom mount refrigerators the rear panel will need to be removed in order to test and replace the component. Remove the light cover by pressing in on the cover’s front. This will release the clips that hold the light cover in place.

With the refrigerator light cover removed the evaporator cover will need to be removed next, remove each small Philip screw located on each end. When removed the fan motor cover will slide forward and off. Next remove the screws located on the top edge of the rear panel. Once removed the refrigerator’s back panel will fall forward enough to lift out of the clips that hold it on the bottom.

The cold control is mounted to the back of the rear panel. The temperature knob sits on the shaft of the cold control. Remove the temperature knob followed by the nut that holds the control to the back panel. Once off we can now test the cold control.

Remove the two wires on the control. Next set your volt meter to ohm setting (a continuity test is also acceptable). Touch both volt meter leads to the cold control leads. If the control is room temperature the meter should beep or a resistance reading on the terminals will indicate a normally operating control.

When the cold controls bulb warms up contact is made inside sending voltage to the compressor and condenser fan motor. Once the control is satisfied contact is broken and the compressor and fans shut down.  If the control is satisfied and an ohm test is made resulting in no resistance or continuity this could be because the control contact is in the open position.

If no volt meter is available or you are not able to read a volt meter, bypassing the thermostat is an option. To learn how to do so you can post your question in our DIY repair forum and a certified technician will assist you with your Sub Zero or appliance repair question.

Sub Zero Repair Forum

Feb 212011

Sub Zero Refrigerators have several common repair jobs made on them, one of which is water in the bottom of the refrigerator side on freezer on bottom models. When water pools in the fresh food side of a Sub Zero refrigerator the source is usually from the drain pan.

Even though Sub Zero refrigerators are dual system units, meaning separate compressors and evaporators, they still go through a defrost cycle. When the compressor pumps the freon to the refrigerator’s evaporator a light frost pattern will form.  This frost is actually absorbing heat inside the refrigerator pushing it through the refrigeration system and finally dissipates at the condenser coil. Ever heard someone tell you keep your condenser coils clean?  The above reason is why, the heat cannot dissipate.  If the coils have layers of dirt and dust the heat can’t transfer.

To prevent the evaporator from becoming so thick with ice the refrigeration system can’t work, the evaporator fan won’t be able to circulate the air, the refrigerator must go into a defrost cycle. During this part of the cycle the frost is melted and runs down into the defrost drain catch, then into the drain line down to the drain pan located underneath on Sub Zero Refrigerators.

Sub Zero uses silicone to seal the drain catch to the backside of the refrigerator, over time this silicone will break down and water will bypass through. When this happens you will see water in the bottom side of the refrigerator, pulling the crisper drawers and glass top forward will reveal the defrost drain catch.  With access to the drain catch visually inspect the silicone bead on the back edge, more than likely the silicone will be missing or loose, pour a little bit of water in the catch to see exactly where the water is leaking from.

To fix this issue is relatively easy, first you will want to remove the old silicone from the catch. In order to do so take a small putty knife or thin bladed knife and remove the silicone, once removed clean the area that the new silicone bead will be applied to.

Using food grade silicone apply a small bead along the edge of the defrost drain catch, let the silicone dry. Once dry pour water into the pan to ensure a tight seal. Fixing a water issue in a Sub Zero refrigerator floor is simple with the correct tools and guidance, if you require further assistance repairing you Sub Zero or Wolf products you can post your question in our DIY repair forum at any time, an authorized repair technician will assist you with your appliance repair question.

DIY Sub Zero Repair Forum