Rinnai Not Working After a Power Outage
On this page (4 sections)
The Short Answer: After an outage, a Rinnai that will not heat usually has a tripped GFCI or breaker, a controller that is still off, or a code from the interruption (03 means power was lost during a bath fill). Restore power, turn the controller on, and restart once. If the outage happened in freezing weather, check for leaks before restarting, because Rinnai’s freeze protection needs electricity.
Work through it in this order
1. Power to the heater. Check the breaker or service switch. Outdoor units are often on a GFCI; reset it once. If it trips again, leave it off and call for service, especially if the area is wet.
2. The controller. Press On/Off if the display shows the heater is off. On systems with more than one controller, make sure the one you use has Priority.
3. Any code on the display. Rinnai lists 03 as “power interruption during bath fill (water will not flow when power returns).” The fix in the SENSEI manual (opens in a new tab) is to turn off all hot taps and press On/Off twice. Other codes after an outage are handled the same as any time: note the number and use the matching guide, such as code 10 or code 12.
4. One restart. Turn power off for about 30 seconds and back on, then open a hot tap.
If it was freezing during the outage
Rinnai heaters protect themselves from freezing with electric heaters, and the manual says protection depends on both gas and 120-volt power. Rinnai’s non-condensing data sheets even list a code for it: 02, “no burner operation during freeze protection mode.” When power is lost in freezing weather, the manual recommends draining the heater.
If the heater sat without power below freezing:
- Look for ice or water at the connections under the unit and around the cabinet.
- If anything is frozen, do not operate it. Follow what to do when a Rinnai freezes.
- If water drips from inside the cabinet after it thaws, keep it off and call a technician.
When the outage damaged something
A surge can damage the control board or the controller. Signs include a display that shows random characters, a heater that clicks without running, or a GFCI that holds but the heater stays dead. A technician checks the supply voltage and the board. Adding surge protection for the heater’s circuit is worth discussing afterward.
A tripped GFCI that will not stay reset, or a breaker that will not reset, means a fault the technician needs to find. Do not hold a breaker on.
Related: Rinnai control panel not working, Navien after a power outage, and water heater beeping after a power outage.
Frequently Asked Questions
Q: Will a Rinnai work during a power outage? A: No. Even though it burns gas, it needs electricity for its controls, fan, and ignition. It will not heat until power is restored.
Q: Can I run a Rinnai on a generator? A: A properly connected generator with a transfer switch can power it, and it keeps freeze protection running. Have an electrician confirm the connection; never back-feed through an outlet.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- Rinnai: RSC SENSEI installation and operation manual (100000773), sections 4.3.5 and 5.6 (opens in a new tab)Rinnai RSC SENSEI models: code 03 and freeze protection requirements.
- Rinnai: RL75i/RL94i technical data sheet (U287-1817x01), error codes (opens in a new tab)Rinnai RL75i and RL94i; code 02 and code 03 descriptions.
- Rinnai: official document library (opens in a new tab)Select your exact model and owner manual before interpreting a fault or reset procedure.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
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