Rinnai code 03: Power cut during bath fill
Continuous flow hot water system (Australia), tankless water heater (United States)
Power to the heater was interrupted while a bath fill was running. Hot water stays off after the power comes back until the controller is reset.
You can often clear this yourself. Work through the causes below in order, most likely first.
What causes it
Australian models
-
A power outage, or the heater being switched off at the power point, while a bath fill was in progress.
Restart hot water after a power cut during bath fillYou can do this
- Turn off all hot water taps.
- Press the On/Off button on the water controller twice.
- Turn a hot tap back on. If the code comes back after three resets, book a service.
US models
-
A power outage or the heater losing power during a bath fill.
Same check as above: Restart hot water after a power cut during bath fill
-
If the code keeps returning after three resets, the control board needs replacing.
How to read this code on your unit
Booking a licensed gas technician
Book a licensed gas technicianlicensed gas technician
- Turn the unit off and leave the covers on. Gas components must only be serviced by a licensed technician.
- Note the code, how often it appears, and the model and serial numbers from the rating label.
- Book a licensed gas technician and give them those details.
Models that show this code
73 models in 15 ranges
| Range | Models |
|---|---|
| Heavy Duty (commercial) | REU-AM3237WC (HD32e), REU-VCM2837FFC (HD28i), REU-VCM2837WC (HD28e), REU-NB3237WC-AK (Heavy Duty 32C), REU-NB3237FFC-AK, REU-NB3237WC-50-AK, REU-NB3237FFC-50-AK |
| Infinity | REU-AM3237W (Infinity 32), REU-AM2626WDL (Infinity 26 Touch), REU-AM2626WD (Infinity 26), REU-AM2024WD (Infinity 20), REU-AM1620WD (Infinity 16), REU-AM1220WD (Infinity 12), REU-A2626WB (B26), REU-A2024WB (B20), REU-A1620WB (B16) |
| Infinity B | REU-BM2626W (Infinity B26), REU-BM2024W (Infinity B20), REU-BM1620W (Infinity B16), REU-BM1220W (Infinity B12) |
| Infinity Enviro | REU-E2626W (Infinity Enviro 26), REU-E1620W (Infinity Enviro 16), REU-NB3237W-AK (Infinity Enviro 32), REU-NB3237W-50-AK |
| Infinity internal | REU-VCM2837FF (Infinity 28i) |
| Commercial (KB) | C199i (REU-KBD3237FFUDC-US), C199e (REU-KB3237WDC-US) |
| KB | RU80i (REU-KB2530FFUD-US), RU80e (REU-KB2530WD-US), RU90e (REU-KBD2934WD-US), RU98i (REU-KB3237FFUD-US), RU98e (REU-KB3237WD-US) |
| KBD | RUC80i (REU-KBD2530FFUD-US), RUC90i (REU-KBD2934FFUD-US), RUC98i (REU-KBD3237FFUD-US) |
| KBP | RUR98i (REU-KBP3237FFUD-US), RUR98e (REU-KBP3237WD-US) |
| KCM | RUCS65i (REU-KCM2025FFU-US), RUCS75i (REU-KCM2528FFU-US), RUS65e (REU-KCM2025W-US), RUS75e (REU-KCM2528W-US) |
| Luxury (VC) | RL75i (REU-VC2528FFUD-US), RL75i(A) (REU-VC2528FFUD-US(A)), RL75e (REU-VC2528WD-US), RL75e(A) (REU-VC2528WD-US(A)), RL94i (REU-VC2837FFUD-US), RLX94i (REU-VC2737FFUD-US), RL94e (REU-VC2837WD-US) |
| SENSEI commercial | CU199i (REU-N3237FFC-US), CU160i (REU-N2530FFC-US), CU199e (REU-N3237WC-US), CU160e (REU-N2530WC-US) |
| SENSEI residential | RU199i (REU-N3237FF-US), RU180i (REU-N2934FF-US), RU160i (REU-N2530FF-US), RU130i (REU-N2024FF-US), RU199e (REU-N3237W-US), RU180e (REU-N2934W-US), RU160e (REU-N2530W-US), RU130e (REU-N2024W-US) |
| SENSEI residential with pump | RUR199i (REU-NP3237FF-US), RUR160i (REU-NP2530FF-US), RUR199e (REU-NP3237W-US), RUR160e (REU-NP2530W-US) |
| Value (VC) | V53e (REU-VAM1620W-US), V53De (REU-AM1620WD-US), V65i (REU-VC2025FFU-US), V65e (REU-VC2025W-US), V75i (REU-VC2528FFU-US), V75e (REU-VC2528W-US), V94i (REU-VC2837FFU-US), V94Xi (REU-VC2737FFU-US), V94e (REU-VC2837W-US) |
Where this comes from
- Error codes for gas continuous flow water heaters (HW Gas CF ERR) , page 1
- Infinity gas continuous flow operation and installation manual , page 12
- Infinity Enviro 32 / HDC32 operation and installation manual , page 12
- Troubleshooting tankless water heater diagnostic codes (100000652), non-SENSEI and SENSEI series , page 7
- N Series residential condensing installation and operation manual (100000467), RU199e/RU180e/RU160e/RU130e , page 59
Checked against the manufacturer's manual on 9 October 2026.
Other Rinnai tankless water heater codes
| Code | Meaning | What you can do |
|---|---|---|
| 02 | Burner did not light during freeze protection | Safe checks first, then a pro |
| 05 | Bypass flow control failure | Safe checks first, then a pro |
| 10 | Air intake, flue or condensate blockage | Safe checks first, then a pro |
| 11 | No ignition | Safe checks first, then a pro |
| 12 | Flame failure or low gas flow | Safe checks first, then a pro |
| 13 | Combustion fault | Safe checks first, then a pro |
| 14 | Overheat safety device tripped | Call a pro |
| 15 | Venturi control failure | Safe checks first, then a pro |
| 16 | Over-temperature shutdown | Safe checks first, then a pro |
| 17 | Venturi blockage | Safe checks first, then a pro |
| 18 | Gas valve adjustment limit | Call a pro |
| 19 | Electrical earth fault | Call a pro |