Rinnai Tankless Heater Error Codes
Rinnai RE Series tankless water heaters feature a built-in diagnostic system that displays error codes whenever the unit detects a fault or abnormal operating condition. These codes can help service technicians quickly identify the affected component, narrow down potential causes and perform troubleshooting more efficiently. Handle error codes and get tankless heaters back up to functional with our helpful guide. Below we have a variety of Rinnai tankless heater error codes and the recommended solutions to streamline the necessary repairs.
Error Code 10
Error Code 10 indicates an issue with the air supply or exhaust venting. This typically occurs when airflow is blocked or improperly configured.
Recommended Solutions:
- Inspect flue inlet and exhaust for obstructions and remove debris
- Verify venting is installed according to manufacturer specifications
- Check for proper connections on vent components
- Check fan for blockage
- Verifying that High Altitude settings are set correctly
Error Code 11
Error Code 11 indicates ignition failure, meaning the heater isn’t turning on.
Recommended Solutions:
- Confirm gas supply is on and properly connected
- Purge air from the gas line
- Inspect and clean the igniter assembly
- Check gas pressure and adjust if necessary
- Verify proper grounding and wiring connections
- Ensure gas line, meter and regulator is sized properly
- Check for loose or disconnected electrical connections
- Inspect the flame rod and clean if necessary
- Verify parameter setting are correct
- Ensure igniter is working
- Check the igniter harness for any damageÂ
- Check gas solenoid valves for open circuits
Error Code 12
You’ll see error code 12 if there’s a flame failure.
Recommended Solutions:
- Verify stable gas supply and proper pressure
- Clean and inspect the flame rod/sensor
- Check venting system for restrictions or leaks
- Inspect condensate drain and ensure proper drainage
Error Code 14
Error Code 14 signals an overheat condition or thermal fuse issue, causing the system to shut down for safety.
Recommended Solutions:
- Check for airflow restrictions around the unit
- Inspect the vent termination for blockages
- Verify the installed gas type matches the heater configuration
- Check for low flow conditions causing short cycling in recirculation systems
- Inspect the combustion chamber and exhaust piping for foreign material
- Examine the heat exchanger for cracks or separation
- Look for hot spots caused by scale accumulation
- Flush the heat exchanger if scale buildup is present
- Treat hard water conditions to prevent future scale formation
- Measure safety circuit resistance
- Verify high-fire and low-fire manifold pressure
- Confirm the unit was converted correctly, if applicable
Error Code 16
Error Code 16 indicates that the outlet water temperature has exceeded safe operating limits.
Recommended Solutions:
- Check for restricted airflow around the unit
- Inspect the vent termination for obstructions
- Verify adequate water flow in recirculation systems
- Check the combustion chamber and exhaust piping for debris
- Inspect the heat exchanger for blockages
- Clean scale buildup from the thermistor sensor
Error Code 19
Error Code 19 means that there could be an electrical grounding issue.
Recommended Solutions:
- Inspect all components for electrical shorts
Error Code 32
Error Code 32 indicates an outgoing water temperature thermistor fault.
Recommended Solutions:
- Inspect thermistor wiring for damage
- Measure thermistor resistance
- Remove scale buildup from the sensor
- Replace the sensor if necessary
Error Code 33
Error Code 33 indicates a heat exchanger thermistor fault.
Recommended Solutions:
- Inspect sensor wiring for damage
- Measure sensor resistance
- Replace the sensor if testing indicates failure
Error Code 34
Error Code 34 indicates a combustion air temperature thermistor fault.
Recommended Solutions:
- Check for airflow restrictions around the unit
- Inspect vent terminations for blockage
- Check the sensor wiring for damage
- Measure sensor resistance
- Verify the fan blade is secure on the motor shaft
- Inspect the fan blade for damage
- Replace the sensor if necessary
Error Code 41
Error Code 41 indicates a freeze protection thermistor fault.
Recommended Solutions:
- Inspect sensor wiring for damage
- Measure sensor resistance
- Replace the sensor if necessary
Error Code 51
Error Code 51 indicates an inlet water temperature thermistor fault.
Recommended Solutions:
- Inspect sensor wiring for damage
- Measure sensor resistance
- Replace the sensor if necessary
Error Code 52
Error Code 52 indicates a modulating solenoid valve signal fault.
Recommended Solutions:
- Inspect the gas valve wiring harness for loose connections
- Check for damaged terminals
- Measure valve coil resistance
Error Code 61
Error Code 61 indicates a combustion fan fault.
Recommended Solutions:
- Verify the combustion fan rotates freely
- Inspect the motor wiring harness for damage
- Check for loose electrical connections
- Measure motor winding resistance
Error Code 63
Error Code 63 indicates low recirculation flow.
Recommended Solutions:
- Clean debris from the inlet water filter
- Verify recirculation parameter settings
- Confirm proper pump supply voltage
- Inspect pump and PCB wiring harness connections
- Remove trapped air from the recirculation line
Error Code 65
Error Code 65 indicates a water flow servo fault.
Recommended Solutions:
- Measure water flow control resistance values
- Verify water flow control voltage readings
- Ensure the connector and harness are dry
- Replace the PC board if voltage readings are abnormal
- Replace the water flow servo valve if PC board output is normal
Error Code 66
Error Code 66 indicates a bypass flow servo fault.
Recommended Solutions:
- Measure bypass servo valve resistance values
- Verify bypass servo valve voltage readings
- Ensure the connector and harness remain dry
- Replace the PC board if voltage readings are abnormal
- Replace the bypass servo valve if PC board output is normal
Error Code 70
Error Code 70 indicates a PC board fault.
Recommended Solutions:
- Inspect the wiring harness connection at the PC board
- Replace the PC board if required
Error Code 71
Error Code 71 indicates a solenoid valve circuit fault.
Recommended Solutions:
- Verify the PCB dip switch is in the OFF position
- Check gas solenoid valves for shorts
- Inspect for grounding issues in the gas valve circuit
- Verify the heater circuit isn’t grounded
- Replace the PC board if necessary
Error Code 72
Error Code 72 indicates a flame sensing device fault.
Recommended Solutions:
- Verify the flame rod is positioned in the burner flame
- Inspect the flame rod and wiring for damage
- Remove and clean carbon buildup from the flame rod
- Inspect the burner chamber for debris affecting flame detection
- Check flame rod resistance to the cabinet
- Replace the PC board if no issues are found with the rod or wiring