Rinnai HE Series How To Use Manual page 185

NOTE: Before servicing product disconnect power supply to the unit.
1. Check wiring harnesses to flame rods for broken or damaged connections from flame rod back
to PC board.
2. Ensure flame rod is touching flame when unit fires.
3. Remove flame rod and check for carbon build‐up. Clean flame rod with dollar bill.
4. Check inside burner for debris build up that may be shorting out flame rod. If debris on the
burner is touching flame rod this could cause a short circuit and throw a code 72.
5. Measure micro amp output from flame rod, should maintain a minimum of 1 micro amp.
6. Replace flame rod, flame rod gasket and PC board.
Code 72 Troubleshooting Procedure
Flame Sensing Device Fault
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