Rinnai Water Heater Error Code 72: How to Fix It

Q: What causes Rinnai error code 72?

Error code 72 is caused by a faulty flame sensing device (flame rod). This can happen due to corrosion, carbon buildup, cracked ceramic insulator, or electrical connection problems that prevent proper flame detection.

Q: Can I clean the flame rod instead of replacing it?

You can try cleaning the flame rod with fine steel wool or emery cloth to remove corrosion and buildup. However, if the ceramic insulator is cracked or the rod is severely corroded, replacement is necessary for safe operation.

Q: How much does a Rinnai flame rod cost?

Replacement flame rods for Rinnai water heaters typically cost between $15-40 depending on the model. Generic flame rods may be available for less, but OEM parts are recommended for proper fit and safety.

Q: Is it safe to use my water heater with error code 72?

No, do not use the water heater with error code 72. This error indicates the safety system cannot detect flame properly, which could lead to gas buildup and dangerous conditions. Repair the fault immediately.

Q: How often should flame rods be replaced?

Flame rods typically last 3-5 years but may need replacement sooner in areas with hard water or corrosive conditions. Regular annual maintenance can help identify flame rod issues before they cause error codes.

Abstract

Rinnai error code 72 indicates a flame sensing device fault, which means the flame rod (also called flame sensor) is not properly detecting the burner flame. This safety feature prevents gas from flowing when no flame is present, so immediate attention is required to restore safe operation.