Rinnai Tankless Error Codes
Rinnai tankless water heater codes are two-digit numbers (plus "LC") that the controller shows when the heater stops itself to stay safe. Find your code below, do the owner checks on its page, and call a technician if it comes back, because most fixes past the gas valve and vent cap happen inside the cabinet.
The codes owners see most
These meanings come from Rinnai's technical bulletin on its condensing water heater codes.
| Code | Rinnai's name for it | Start with |
|---|---|---|
| 10 | Air supply or exhaust blockage | The vent and intake outside |
| 11 | No ignition | Gas valve, meter and propane tank |
| 12 | Flame failure | Gas supply and the vent |
| 14 | Thermal fuse | Call a technician |
| 16 | Over temperature warning | Airflow and scale, then a technician |
| 25 | Condensate trap error | The condensate drain line |
| 52 | Modulating solenoid valve signal abnormal | Call a technician |
| 61 | Combustion fan failure | Call a technician |
| LC | Scale build-up in heat exchanger | Flush the heater |
LC is the odd one out. Rinnai says it's the only code that lets the unit keep running. The display alternates between LC and your temperature setting until the heat exchanger is flushed.
Gas, flame and ignition codes
These are the ones that leave you with cold water mid-shower. Check that gas is on at the heater and meter, that a propane tank isn't empty, and that the vent outside is clear.
- Rinnai code 11: the burner never lit.
- Rinnai code 12: the burner lit, then lost its flame.
- Rinnai code 10: blocked air supply or exhaust.
Overheat, fan and component codes
These mostly point inside the unit. Write the code down and book a technician.
- Rinnai code 14: the thermal fuse tripped.
- Rinnai code 52: a gas valve signal fault.
- Rinnai code 61: the combustion fan.
- Rinnai code 79
Reading and clearing a code
The code shows on the controller when the heater faults. On RL-series models, Rinnai's technical sheet says you can page back through past codes by pressing the ON/OFF button followed by the thermostat button. Rinnai's troubleshooting guide resets some codes by pressing the ON/OFF button twice, but if the cause is still there the code comes back, often on the next hot tap.
When you call for service, give the tech every code you've seen, the model number from the rating plate on the side of the unit, and when the problem happens. Rinnai's bulletin also notes that maintenance history records LC as "00", so a tech can see whether the unit has been asking for a flush.
Other brands
The numbers don't carry over between brands, even when they look alike. Use the page for your heater:
All guides in this section
Look up an error code
Sources
- Rinnai CorporationCondensing Water Heater Error Codes, Technical Bulletin TB-75 (opens in a new tab)
- Rinnai CorporationRL75i / RL94i technical sheet U287-1817 (opens in a new tab)
- Rinnai CorporationTroubleshooting Tankless Water Heater Diagnostic Codes (100000652) (opens in a new tab)