- The chiller displays AL368 – CpCOe Offline, which points to an internal control issue: the expansion control board (often an auxiliary control module) is not responding or has lost communication with the main controller. As a result, the chiller either shuts down or certain functions are halted for safety.
- You might notice that some parts of the chiller that are managed by the expansion board are not operating. For example, if that board controls some valves or sensors, those readings might be blank or those components inactive. The main display may show an error status, and the alarm won't reset until communication is restored.
- There may not be many external physical clues (no leaks, no unusual noises) because this is an electronic/control fault. One clue could be that this alarm often appears on startup or after a power fluctuation. It could also appear after someone was working in the control panel (possibly leaving a cable loose).
Loose or Disconnected Communication Cable
The expansion board is typically connected by a communication harness (like a CAN bus or serial cable) to the main board. If this cable came loose or got disconnected (vibration, maintenance mishap), the main controller will flag the board as offline.
Power Supply Issue to the Board
The board might not be powered due to a blown low-voltage fuse or a bad connection in the power supply wiring. No power to the board = no communication.
Board Failure or Fault
It's possible the CpCOe (expansion board) itself has failed electronically. Overvoltage, water ingress, or just component failure could make it unresponsive.
Software/Firmware Glitch
In some cases, a firmware incompatibility or glitch can cause communication errors. If the controller was recently updated or reconfigured, a software mismatch might be to blame (though this is less common in stable running systems).
Power Cycle the Chiller Control
The first step in electronics issues – turn off the chiller power, wait 1-2 minutes, and turn it back on. Sometimes the board might simply need to reboot and will resume communication after a hard reset. This can clear minor glitches.
Inspect Connections on the Expansion Board
With power off, open the control panel. Check that all cables to the CpCOe board are firmly seated. This includes any ribbon cables, plug connectors, or communication wires. Gently press in each connector to ensure none are loose. Also verify the board is securely mounted and no visible damage (burn marks or popped capacitors).
Check Fuses and Power LEDs
Look for any small fuses on the control boards (often there are low-voltage fuses for the control circuit). If you find a blown fuse, replace it with the exact same rating. Some boards have a power LED – confirm if it's lit on the CpCOe board. No light could mean no power to it.
Reset the Alarm
After ensuring connections are good and powering the unit back up, try resetting AL368. If the board comes online, the alarm will clear and the chiller might resume normal operation. Watch the startup sequence to see if all systems initialize without errors.
Swap Boards (if available)
If you happen to have a similar unit or a spare board, and you're technically adept, you could swap the suspected bad board to see if that resolves the issue. (Only do this if the manufacturer procedures allow; otherwise, leave to professionals.)
Professional Help Required:
- If the CpCOe offline alarm persists after reconnecting cables and power-cycling
- Board replacement needed - requires proper configuration and addressing
- Complex wiring issues or damaged communication harnesses
- If you're not comfortable working with electronic control boards
A qualified technician can run diagnostics on the control boards and determine if the expansion board has failed. They may try uploading firmware or using a service tool to ping the board. The chiller won't run properly without resolving this issue, and working with control electronics requires specialized knowledge to avoid further damage.