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A108

A108 - Ignition Board Communication Failure

Rheem · Water Heaters

What does A108 mean?

Communication has been lost between the display board and the ignition control board. The ignition control board will continue operating with the last known settings.

Common Causes

  • Loose wiring between boards
  • Faulty display board
  • Faulty ignition control board

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the wiring between the display board and P5 of the ignition control board.

  2. 2

    If the problem persists, contact technical support or a service provider.

Browse all codes in this manual (70)
Verified technical data. Last updated: April 2026

Related Faults

1111 - Gas shut-off valve is not fully open1212 - Gas service interrupted or LP gas low13Hot and cold water lines reversed
Source: Rheem Water Heaters
Open Manual (Page 46)Search more codes in this manual