COM
Heliocol
Communication Link Failure Between Solar Controller and Pool Automation
Controller displays COM or COMM and does not respond to automation commands from the main pool control system.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Disconnected low-voltage communication cable, Reversed polarity on data bus, Incompatible protocol settings, Corroded terminal block on controller board
How to Fix / Troubleshooting
Safety first: Turn off low-voltage power to the automation and solar controller before changing communication wiring.
- Check cable connections: Inspect the communication cable between the main automation panel and the solar controller. Ensure all conductors are firmly landed on the correct terminals and that polarity matches at both ends.
- Inspect for corrosion: Look for green or white corrosion on terminal blocks. Clean lightly with contact cleaner and a small brush, or replace the terminal block if badly damaged.
- Verify protocol settings: On systems that allow it, confirm that the solar controller is set to the correct communication mode or address expected by the main automation.
- Test with short jumper: Temporarily connect the solar controller to the automation panel with a short known-good cable to rule out cable damage in the conduit run.
- Reboot both systems: Power-cycle the automation and solar controller to clear transient communication errors and check if the COM error clears.
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Repair Difficulty
Medium
3/5
Required Part
Solar Controller Main PCB
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