HVACopediaRinnai · Tankless water heater
79 Water leakage detected
What the control is telling you
The internal leak detector has sensed water inside the cabinet, or the leak sensor/its wiring is faulty.
Applies to: Non-SENSEI Series
Likely causes
- Leaking heat exchanger or internal piping
- Water pooled on the cabinet bottom pan
- Wet leak sensor
- Loose, broken or damaged leak detector wiring
- Failed leak sensor
Test and repair steps
- Inspect the leak detector wiring and connections for loose, broken or damaged parts.
- Check the heat exchanger and all internal piping for leaks.
- If no leak is found, look for water pooled on the bottom pan; wipe or blow it out, dry the leak sensor and restart the heater.
- If the cabinet is dry, unplug the sensor and fire the heater; if it runs with the sensor unplugged, replace the sensor and its screw.
Settings for these units
- RUCS/RUS unit clearances · Non-SENSEI
- RUCS/RUS water quality limits · Non-SENSEI
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Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), p.62. Summarized in our own words; check the original manual for your model.
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