Rinnai Error Code 12: Flame failure (Tankless)
Rinnai error code 12 on a tankless water heater means: Flame failure. It is also called Rinnai diagnostic code 12.
Homeowner? What Rinnai code 12 means for you
Call a technician Your tankless water heater is reporting: Flame failure. The tankless water heater has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
Safe things you can check yourself
- Check that gas reaches the house: other gas appliances work, or the propane tank is not empty.
- Make sure the heater is plugged in and its breaker is on. In winter, keep the power on: it protects the unit from freezing.
- Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
- Check that the hot and cold water valves under the heater are fully open.
- If you have a remote controller, turn it off and on once. If the code comes back, call a technician.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does Rinnai error code 12 mean?
The flame went out or was lost after ignition. If code 12 shows right as water starts flowing with no visible flame (SENSEI), suspect an electrical short in a DC circuit component.
Applies to: SENSEI, SENSEI RX/CX and non-SENSEI tankless
Common causes of Rinnai code 12
- Gas off, propane tank empty, or inlet pressure low from undersized piping
- Loose electrode or flame rod, wrong electrode gap, or damaged flame rod wiring
- Cracked or heat-damaged flame rod silicone sleeve letting the spark ground outside
A technician checks these and 5 other possible causes on site before replacing any part.
Rinnai models that use code 12
Show all 89 models
C199eC199iCU160eCU160iCU199eCU199iCX160iCX199iCXP160iCXP199iR50LSiR63LSe2R75LSeR75LSiR94LSeR94LSiR98LSeR98LSe-ASMER98LSiR98LSi-ASMERC80eRC80iRC98eRC98iRE140eRE140iRE160eRE160iRE180eRE180iRE199eRE199iREP160eREP160iREP199eREP199iRH180RL75eRL75e(A)RL75iRL75i(A)RL94eRL94iRLX94iRSC160eRSC160iRSC199eRSC199iRU80eRU80iRU90eRU98eRU98iRU130eRU130iRU160eRU160iRU180eRU180iRU199eRU199iRUC80iRUC90iRUC98iRUCS65iRUCS75iRUR98eRUR98iRUR160eRUR160iRUR199eRUR199iRUS65eRUS75eRX130iRX160iRX180iRX199iRXP160iRXP199iV53DeV53eV65eV65iV75eV75iV94eV94iV94Xi
Other Rinnai Tankless codes
All Rinnai Tankless Water Heater error codes →
Rinnai code 12: homeowner questions
What does Rinnai code 12 mean?
Flame failure. The flame went out or was lost after ignition. If code 12 shows right as water starts flowing with no visible flame (SENSEI), suspect an electrical short in a DC circuit component.
Is it safe to keep using my tankless water heater with code 12?
It depends on the cause. The tankless water heater has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.
Can I reset Rinnai code 12 myself?
You can try one reset (power off for 30 seconds, then on). If Rinnai code 12 comes back, the cause is still there and a licensed technician should check it.
Who can fix Rinnai code 12 near me?
Aurora Star Tech Inc. repairs Rinnai tankless water heaters in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Tankless Water Heater No Hot Water: What to Check
Troubleshooting guides
- No hot water All brands · Tankless Water Heater
- Water temperature fluctuates All brands · Tankless Water Heater
Source: Rinnai Troubleshooting TWH Diagnostic Codes (100000652), p.20–21. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.