E13
Pentair Communication Fault (External Controller / RS-485)

Heater shows E13 and will not respond to thermostat commands.

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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

Faulty RS-485 communication cable, Incorrect wiring polarity on automation bus, External automation system not configured correctly, Control board communication port failure

How to Fix / Troubleshooting

Safety: Turn off power to the heater and automation system before working on low-voltage wiring.

  • Check RS-485 wiring: Inspect the communication cable between the heater and Pentair automation (e.g., IntelliCenter, EasyTouch). Verify correct polarity (A/B) and that shield/drain is properly terminated.
  • Look for cable damage: Replace any cable that is nicked, crushed, or water-damaged.
  • Test heater in standalone mode: Temporarily disconnect the RS-485 cable and operate the heater from its local control panel. If it works locally, the issue is likely with the automation wiring or controller.
  • Reconfigure automation: Ensure the heater is correctly added and addressed in the automation system menu. Consult Pentair automation manuals.
  • Board port failure: If communication still fails with known-good wiring and controller, the heater’s control board communication port may be defective and require replacement.
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Repair Difficulty

Medium 3/5

Required Part

Main Control Board
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