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NOTICE: Wait ninety (90) seconds after power is connected for the first time

NOTICE: Wait 90 seconds after initial power connection

Rheem · Tankless Water Heaters

What does NOTICE: Wait ninety (90) seconds after power is connected for the first time mean?

When power is connected for the very first time, the water heater requires a 90-second period to initiate its startup sequence. Please allow this time before expecting the unit to operate.

Common Causes

  • Attempting to use the unit immediately after first-time power connection

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Connect the electrical power supply.

  2. 2

    Wait at least 90 seconds for the unit to initialize.

  3. 3

    Check for normal operation after the waiting period.

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

Related Faults

88Error 88 — Maintenance required before clearing codeAlarm/Error IndicatorSystem Alert — An issue has been detectedDANGER: Shock HazardDANGER: Shock Hazard — Electrical power is present
Source: Rheem Tankless Water Heaters
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