Rinnai Error Code 73: Circuit Board Setting Error
Warning: Your Rinnai water heater has detected a circuit board setting error, which may affect its functionality. It's safe to operate, but a professional should address it.
How to Fix Rinnai Code 73
- Check if any recent power fluctuations or user interventions might have caused the issue.
- If you've recently changed any settings, try resetting them to default using the control panel.
- If the issue persists, contact a professional Rinnai technician for further diagnosis and repair.
How to Reset Rinnai Code 73
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.
What Does Rinnai Error Code 73 Mean?
Rinnai's error code 73 indicates a circuit board setting issue in your water heater. This could be due to a software glitch, a faulty board, or incorrect settings. The system might not function optimally, but it's safe to use until a professional resolves the issue.
Common Causes
- Software glitch on the circuit board
- Faulty circuit board
- Incorrect settings due to power fluctuations or user intervention
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Water heater is not heating or functioning properly | Check the circuit board for any visible signs of damage or corrosion | No visible damage or corrosion |
| Circuit board appears intact | Perform a power reset by turning off the water heater at the circuit breaker, then turning it back on after 30 seconds | Error code 73 clears, and the water heater functions normally |
Applicable Rinnai Models
- CU(gas)
- HE(dual_fuel)
- HE++ Series(gas)
- I-SERIES(gas)
- NCB(gas)
- NPE(gas)
- RE(gas)
- REP(gas)
- RL(gas)
- RU(gas)
- RUCS(gas)
- RX(gas)
- RXP(gas)
- Rinnai NCB Series(gas)
- Rinnai NPE Series(gas)
- Rinnai R Series(gas)
- Rinnai RL Series(natural_gas)
- Rinnai RU Series(natural_gas)
- Rinnai RUR Series(gas)
- Rinnai VSP(gas)
- V(gas)
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Circuit Board | RIN-123456 | — | Find Part |
Related Codes on Same Models
Other codes that affect the same Rinnai model families as 73.
| Code | Description | Severity |
|---|---|---|
| 02 | Stagnant Water Detection | Warning |
| 10 | Air Supply/Exhaust Blockage | Warning |
| 11 | No Ignition | Warning |
| 12 | Flame Failure | Warning |
| 14 | Thermal Fuse | Warning |
| 16 | Over-Temperature | Warning |
| 19 | Electrical Grounding | Warning |
| 25 | Condensate Overflow | Warning |
| 29 | Condensate Neutralizer | Warning |
| 31 | Inlet Thermistor Failure | Warning |