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Alarm/Error Indicator

System Alert — An issue has been detected

Rheem · Tankless Water Heaters

What does Alarm/Error Indicator mean?

The 'Alarm/Error Indicator' light illuminates when the water heater detects a fault or requires attention. The specific issue may be displayed on the LED screen or indicated by an error code.

Common Causes

  • System fault detected.
  • Maintenance required.
  • Error code present on display.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the LED display for any error codes.

  2. 2

    Refer to the troubleshooting section of the manual for the displayed code.

  3. 3

    If no code is displayed, consider basic troubleshooting like resetting the unit.

  4. 4

    Contact qualified service personnel if the issue persists.

Browse all codes in this manual (24)
Verified technical data. Last updated: April 2026

Related Faults

88Error 88 — Maintenance required before clearing codeDANGER: Shock HazardDANGER: Shock Hazard — Electrical power is presentDedicated circuit is recommendedRecommendation: Use a dedicated electrical circuit
Source: Rheem Tankless Water Heaters
Open Manual (Page 54)Search more codes in this manual