Bypass Defrost Board For Cooling

Many refrigerators and freezers use a defrost board to automatically remove frost buildup from the evaporator coils. Sometimes, these boards fail, leading to issues like excessive frost accumulation or the compressor not running. Bypassing the defrost board can provide a temporary solution, allowing the unit to cool until the board can be replaced. This method is particularly useful in situations where food spoilage is a concern, such as a restaurant experiencing a board failure on a busy weekend or a homeowner waiting for a replacement part to arrive.

Identifying the Defrost Board

Locate the defrost board within your refrigerator or freezer. Its position varies depending on the appliance's brand and model. Typically, you can find it behind a panel in the back of the freezer compartment, often near the evaporator coils or the compressor compartment. Consult your appliance's service manual for a precise location if you're unsure.

The defrost board is usually a small circuit board with multiple terminals. It's often encased in a plastic housing. Before proceeding, carefully examine the board for any visible signs of damage, such as burnt components or loose wiring. Note the wiring configuration; taking a picture with your phone before disconnecting anything is highly recommended.

Gathering Necessary Tools and Materials

Before starting the bypass procedure, ensure you have the following items:

• Screwdrivers (Phillips and flathead)
• Wire strippers
• Wire connectors (crimp connectors or wire nuts)
• Jumper wire (14-16 gauge stranded wire is suitable)
• Electrical tape
• Safety glasses
• Gloves

Safety is paramount. Always disconnect the refrigerator or freezer from the power source before working on any electrical components. Wear safety glasses and gloves to protect your eyes and hands.

Bypassing the Defrost Board

This involves directly connecting the compressor relay to the power source, effectively skipping the defrost board's control. This is a temporary fix and should only be used until a replacement board is installed.

Step 1: Identifying the Compressor Relay

The compressor relay is usually located near the compressor, often mounted on or near it. It's a small electrical component with several terminals. Identify the terminals connected to the power supply and the compressor. Refer to the wiring diagram (often found inside the refrigerator) to ensure correct identification. Note the colors of the wires connected to the relay.

Step 2: Disconnecting the Original Wiring

Carefully disconnect the wires that currently run from the defrost board to the compressor relay. Use wire strippers to expose a small section of wire on both the power supply wire and the compressor wire. Ensure the refrigerator is unplugged before doing this.

Step 3: Creating the Jumper Wire Connection

Cut a length of jumper wire long enough to comfortably connect the power supply wire to the compressor wire. Strip the insulation from both ends of the jumper wire.

Using wire connectors (crimp connectors or wire nuts), securely connect one end of the jumper wire to the power supply wire and the other end to the compressor wire. Ensure the connections are tight and secure to prevent loose connections or arcing.

If using crimp connectors, use a crimping tool to firmly secure the connection. If using wire nuts, twist the wires together tightly before screwing on the wire nut. Pull gently on the wires to ensure they are securely connected.

Step 4: Insulating the Connections

Wrap each connection with electrical tape to insulate them thoroughly. This prevents short circuits and protects against accidental contact.

Apply multiple layers of electrical tape, overlapping each layer, to ensure complete coverage. Pay close attention to the ends of the wire connectors to prevent any exposed wire.

Step 5: Reconnecting Power and Monitoring

Plug the refrigerator or freezer back into the power outlet.

Monitor the unit to ensure the compressor starts running. You should hear the compressor start and feel it vibrating. Check the temperature inside the freezer and refrigerator compartments to confirm that they are cooling. It may take some time for the unit to reach the desired temperature.

Step 6: Setting a Timer for Defrosting (Manual Defrost)

Since the defrost board is bypassed, the unit will no longer automatically defrost. You'll need to manually defrost the unit periodically to prevent excessive frost buildup. This is crucial to prevent the evaporator coils from becoming blocked with ice, which will reduce cooling efficiency.

Set a timer to remind you to defrost the unit every few days or weeks, depending on the humidity and usage. A good starting point is every 3-5 days. Monitor the frost buildup on the evaporator coils and adjust the defrosting frequency accordingly.

To manually defrost, unplug the refrigerator or freezer. Leave the door open and allow the frost to melt. You can speed up the process by placing a bowl of hot water inside or using a hair dryer (exercise caution and keep the hair dryer moving to avoid overheating). Once the frost has melted, wipe down the interior with a clean cloth and plug the unit back in.

Important Considerations

• This is a temporary solution. Replace the defrost board as soon as possible. Prolonged use without a functioning defrost cycle can lead to damage to the compressor and other components.
• Monitor the temperature inside the refrigerator and freezer closely. If the unit is not cooling properly, even with the bypass, there may be other issues.
• Avoid overloading the refrigerator or freezer, as this can increase the strain on the compressor.
• Be mindful of food safety. Ensure that food is stored at the correct temperature to prevent spoilage.

Alternative Method: Using a Timer Relay (Advanced)

For a slightly more automated solution, you could use a timer relay in place of the defrost board. This involves wiring the timer relay to interrupt power to the compressor for a short period each day, simulating a defrost cycle. This is a more complex modification and should only be attempted by individuals with experience in electrical wiring. It requires understanding relay logic and carefully selecting a timer relay with appropriate settings.

This method involves connecting the compressor power wire to the normally closed (NC) contact on the timer relay. The common (COM) contact of the timer relay is then connected to the compressor. The timer relay is set to briefly switch to the normally open (NO) contact for a set duration (e.g., 20 minutes) at a specific time each day, interrupting power to the compressor and allowing the unit to defrost.

Caution: Incorrect wiring can damage the compressor or other components. Consult with a qualified technician if you are unsure about this procedure.

Troubleshooting Common Issues

Compressor Not Running: Double-check all connections to ensure they are secure. Verify that the jumper wire is making good contact. Test the continuity of the jumper wire to ensure it is not broken. Check the overload protector on the compressor – it may have tripped.

Unit Not Cooling: Make sure the condenser coils (usually on the back or bottom of the unit) are clean and free of dust. Ensure the evaporator fan (inside the freezer) is running. The bypass may not be the complete solution if there are other issues, such as a refrigerant leak or a faulty compressor.

Excessive Frost Buildup: Adjust the defrosting frequency. Increase the frequency if you notice frost building up quickly. Ensure the door seals are tight and that the door is not being opened frequently.

Bypass Defrost Board Checklist

• Safety First: Unplug the refrigerator/freezer. Wear safety glasses and gloves.
• Identify: Locate the defrost board and compressor relay. Take a picture of the wiring.
• Prepare: Gather necessary tools and materials.
• Disconnect: Disconnect wires from the defrost board to the compressor relay.
• Jumper: Create and connect the jumper wire.
• Insulate: Insulate all connections with electrical tape.
• Reconnect: Plug the unit back in.
• Monitor: Verify the compressor is running and the unit is cooling.
• Defrost: Set a timer for manual defrosting.
• Replace: Order and install a new defrost board ASAP.