Rinnai Error Code 99: PCB Replace Required
Warning: Your Rinnai water heater is displaying a 'PCB Replace Required' error. This indicates a problem with the control board, which is not an immediate safety risk but requires professional attention.
How to Fix Rinnai Code 99
- Step 1: Turn off the power to your water heater at the circuit breaker.
- Step 2: Contact a licensed HVAC technician for repair. Do not attempt to open the water heater or replace the PCB yourself.
- Step 3: If you notice any unusual noises, smells, or water leaks, shut off the water heater immediately and contact a professional.
How to Reset Rinnai Code 99
- 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 99 Mean?
The 'PCB Replace Required' error on your Rinnai water heater means that the main control board (PCB) has detected an issue and needs to be replaced. This could be due to a fault in the board itself or a problem with one of the components it controls. The error is displayed on the digital display, typically as '99'.
Common Causes
- Faulty PCB (main control board)
- Problem with a component controlled by the PCB, such as the temperature sensor or pressure switch
- Wiring issue connected to the PCB
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Error code 99 is displayed | Inspect the PCB for any visible damage or signs of overheating | No visible damage |
| PCB appears undamaged | Check the wiring connected to the PCB for any signs of damage or corrosion | No damage or corrosion |
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 |
|---|---|---|---|
| PCB (Main Control Board) | RIN-0012000000 | — | Find Part |
Related Codes on Same Models
Other codes that affect the same Rinnai model families as 99.
| 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 |