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.
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.
It's possible the CpCOe (expansion board) itself has failed electronically. Overvoltage, water ingress, or just component failure could make it unresponsive.
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).
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.
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).
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.
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.
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.)
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.
