Rinnai 03 Error Code: Power interruption during bath fill
Updated October 2026 · Sourced from Rinnai documentation
🧭 Check a few things first
Power was interrupted during a bath fill, so water will not flow when power returns. The manual says to turn off all hot water taps and press ON/OFF twice.
Is it safe to keep running? Check the steps below first. If water still will not flow after pressing ON/OFF twice, call a qualified professional.
03 at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| 03 Code shown on the temperature controller display | Power interruption during bath fill | SENSEI N Series residential condensing: RU199i, RU180i, RU160i, RU130i (indoor) and RU199e, RU180e, RU160e, RU130e (outdoor) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Turn off all hot water taps.
- Press the ON/OFF button twice.
🛑 Stop and call a licensed pro if
- If water still will not flow after pressing ON/OFF twice, call a qualified professional.
- You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
- Codes for flame failure, overheating, venting or the control board that return after one reset.
- Water leaking from the heater, the relief valve discharging, or scorching around the burner area.
- A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.
Safe first steps for any Rinnai code
- Write down the exact code shown on the controller or the number of status light flashes.
- Turn the water heater power off and back on (or press the reset button the manual describes) once. If the code comes back, stop resetting.
- Make sure the gas supply valve to the heater is open and other gas appliances in the home are working.
- Make sure the cold water supply valve is fully open and hot water taps are not partly closed.
- Look at the outside vent terminal for snow, ice, leaves or anything blocking it (look only).
Source: Rinnai SENSEI N Series Residential Installation and Operation Manual (100000467), 5.6 Diagnostic Codes, p.73. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Ryan Giles · Red Seal Certified Plumber · Ask a plumber · Ask an HVAC technician
Related Rinnai codes
05 : By-pass flow control10 : Air supply or exhaust blockage, or condensate trap full11 : No ignition12 : No flame14 : Heat exchanger overheat15 : Venturi control16 : High outgoing temperature17 : Venturi blockage19 : Electrical grounding21 : Data transfer error25 : Condensate pump (accessory)32 : Outgoing thermistor