Rinnai Tankless Water Heater Error Code 24: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
Error Code
24
Brand
Rinnai
Product Type
water_heater
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error code 24 on your Rinnai tankless water heater indicates a servo motor fault. The servo motor controls the gas valve, and this error means it's not operating correctly. This guide will help you troubleshoot and resolve the issue safely.
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Tools You'll Need

How to Fix Error Code 24

  1. Power Cycle the Water Heater

    Ensure power is off before proceeding.
  2. Check for Loose Connections

    Disconnect power before removing covers.
  3. Inspect the Servo Motor

  4. Test the Servo Motor with a Multimeter

    Ensure power is off before testing.
  5. Replace the Servo Motor

    Turn off gas supply and power before servicing gas components.

Parts You May Need

Rinnai Servo Motor
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Rinnai Servo Motor
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Rinnai Servo Motor
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Rinnai Servo Motor
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When to Call a Professional

If the error persists after replacing the servo motor, the control board may be faulty, requiring a professional technician. Also, if you're uncomfortable working with gas components, call a licensed plumber or HVAC technician.

Frequently Asked Questions

What does error code 24 mean on a Rinnai water heater?
It indicates a servo motor fault. The servo motor controls the gas valve, and the error means it's not functioning correctly.
Can I reset a Rinnai error code 24?
Yes, by turning off the power for 60 seconds and turning it back on. However, if the fault persists, further troubleshooting is needed.
How much does it cost to fix Rinnai error code 24?
DIY replacement of the servo motor costs around $50-$100 for the part. Professional repair may cost $200-$400 including labor.
Is it safe to use my Rinnai water heater with error code 24?
No, error 24 may prevent proper gas flow, leading to unsafe operation. Do not use the heater until the issue is resolved.
What tools do I need to fix error code 24?
You'll need a Phillips screwdriver, a multimeter, and possibly a soft brush for cleaning.