72
Noritz Flame Sensing Circuit Abnormality

Error code 72 appears; unit may not detect flame correctly.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Defective flame rod, Short or open in flame rod wiring, PCB flame detection circuit failure, Poor grounding of unit

How to Fix / Troubleshooting

Safety first: Turn OFF power and gas. Allow the unit to cool.

Steps to check and correct:

  • Clean and inspect flame rod: Remove the flame rod and clean the metal probe with fine abrasive pad. Check for cracks in the ceramic and replace if damaged.
  • Inspect wiring: Follow the flame rod wire to the PCB. Look for damage or loose connections. Reseat connectors.
  • Verify ground: Ensure the heater is properly grounded to the electrical system. Tighten ground connections.
  • Reset and test: Restore power and gas. If error 72 persists, the PCB flame sensing circuit may be faulty and should be replaced by a technician.
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Repair Difficulty

Hard 4/5

Required Part

Flame Rod
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