HVACopediaRinnai · Tankless water heater
Bluetooth LED solid Bluetooth LED solid blue (app pairing mode)
What the display is showing
Pressing and releasing the controller's Bluetooth key turns its LED solid blue. The heater is ready to pair with the Rinnai Central app (professional account). One beep means pairing succeeded; two beeps mean pairing time ran out without a connection.
Applies to: Rinnai SENSEI RX/CX tankless (RX, RXP, CX, CXP)
Settings for these units
RX supply connection sizes · SENSEI RX/CX
| Connection | Size |
|---|---|
| Gas | 3/4 in. MNPT |
| Cold inlet | 3/4 in. MNPT |
| Hot outlet | 3/4 in. MNPT |
| Condensate drain | 1/2 in. MNPT |
Vent connection: 2 in. nominal PVC/CPVC/PP or 3 in./5 in. concentric.
Full specs (input, flow, weight) are only on each model's spec sheet, not in this manual.
RX water quality limits · SENSEI RX/CX
| Contaminant | Maximum level |
|---|---|
| Total hardness | Up to 200 mg/L |
| Aluminum | Up to 0.2 mg/L |
| Chlorides | Up to 250 mg/L |
| Copper | Up to 1.0 mg/L |
| Dissolved CO2 | Up to 15.0 mg/L |
| Iron | Up to 0.3 mg/L |
| Manganese | Up to 0.05 mg/L |
| pH | 6.5 to 8.5 |
| TDS | Up to 500 mg/L |
| Zinc | Up to 5 mg/L |
Water damage beyond these limits is not covered by warranty.
- RX water treatment and flushing by hardness · SENSEI RX/CX
- RX clearances to combustibles · SENSEI RX/CX
- RX temperature settings available · SENSEI RX/CX
Models that show this code
10 models in SENSEI RX/CX
Other codes on the same units
- A Venturi reset sequence: step A (RX/CX)
- AdJ Venturi reset sequence: step AdJ (RX/CX)
- Bluetooth LED blinking Bluetooth LED blinking (push-button pairing mode)
- Diag history Maintenance code history viewer (last 9 codes)
- Diagnostic history Show last 9 maintenance codes
- E Venturi reset sequence: step E (code 17 or 52 only)
- ECL Reset complete
- End Descaling procedure ended
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), BLE and App Instructions p.4; Rinnai SENSEI RX Residential Installation and Operation Manual (100000839), 4.12 p.46 and 7.5 p.75. Summarized in our own words; check the original manual for your model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.