Replacing a Refrigeration DC Compressor

Preparation and Refrigerant Removal

Before starting, identify the three key connectors: suction, discharge, and the process connector. To safely begin, you must remove the existing refrigerant (such as R134a):

• Pierce the Tube: Use piercing pliers or a piercing valve to access the process tube.
• Verify Vacuum: Ensure the system is fully evacuated. You should hear air being drawn in when the clamp is removed, confirming a vacuum.
• Safety First: Removing all flammable refrigerant is critical before using a brazing flame.

Removing Components

Once the system is empty, you can begin deconstructing the old setup:

• Unbraze the Compressor: Heat the connections to remove the old unit.
• Replace the Filter Drier: The drier must be replaced whenever a refrigeration circuit is opened.
• Cut the Capillary Tube: Use a specific capillary tube cutter rather than unbrazing it. This prevents the delicate tube from cracking and ensures it remains unobstructed.

Installing the BD Nano

The new compressor requires minor prep work to fit into the existing machine compartment:

• Grommets: Install the supplied rubber grommets by screwing them into the base.
• Mounting: Because the BD Nano may have different dimensions than older units, you may need to drill new mounting holes in the base plate.
• Tube Alignment: Pre-bend the suction and discharge tubes so they align with their final brazing positions.

Brazing and Sealing

With the compressor in place, the circuit must be resealed:

• Schrader Valve: Braze a Schrader valve onto the process tube to allow for future charging.
• Drier Installation: Remove burrs from the tubes to avoid flow restriction. Insert the capillary tube deep enough into the drier (on the outlet side) so that filler material doesn't accidentally seal the opening.
• Alloy Selection: Use Silfos for copper-to-copper joints. For joining different materials like steel and copper, use silver-coated filler metal with flux.

Final Evacuation

The last step before charging is a final evacuation of the system:

• Service Valve: Install the service valve into the Schrader valve using a specialized tightening tool.
• Vacuum Pump: Attach to the evacuation hose and open the valve. The pump will now pull a vacuum; the duration depends on the size of your system.

Hardware Connection and Setup

The setup process begins with unpacking the Gateway, which includes all necessary components in the box. Once the controller is connected to the compressor, the Gateway can be hooked up for programming using the specifically labeled cables.

To ensure a proper connection, follow these wiring steps:

• Positive Terminal: Connect the O-Plus cable to the positive terminal on the compressor controller.
• LIN Contact: Attach the green data cable to the LIN contact.
• C Contact: Attach the brown cable to the C contact.
• USB Interface: Connect the Gateway to a mobile phone using the supplied USB data cable.

Programming via Tool4Cool®

After the system is charged and a connection to the Tool4Cool® app is established, you can start the compressor and begin the programming sequence.

To achieve maximum performance, you can manually adjust the speed settings:

• Increase RPM: Increase the current speed from 3,000 RPM to 4,500 RPM by swiping up within the app.
• Transmit Data: Send the new programming to the controller by pressing the designated button.

Performance Results

Once the controller receives the updated instructions, the compressor starts running at full power. You will observe an immediate drop in temperature as the system stabilizes at the highest performance level.