72
Noritz Flame Rod Signal Abnormality

Boiler shows error 72 and may attempt to start but fails.

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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

Weak flame signal, Dirty or mispositioned flame rod, Poor ground connection, Control board flame circuit fault

How to Fix / Troubleshooting

Safety: Turn OFF power and gas before working near the burner.

  • 1. Clean flame rod: Remove the flame rod from the burner area and gently clean it with fine abrasive pad to remove oxidation. Reinstall in the correct position.
  • 2. Check ground: Ensure the boiler chassis is properly grounded and that ground wires are securely attached. A poor ground can weaken flame sensing.
  • 3. Inspect burner: Clean any debris from the burner surface that could affect flame shape and contact with the flame rod.
  • 4. Professional diagnosis: If error 72 persists, the control board flame detection circuit or the flame rod assembly may need replacement by a technician.
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Repair Difficulty

Hard 4/5

Required Part

Flame Rod
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