Rinnai Water Heaters Error Codes

Air supply or exhaust blockage.

Heater not turning on due to ignition failure.

Flame not detected after ignition attempt.

Thermal fuse tripped.

Safety shutdown because unit is too hot.

Electrical grounding issue.

Outgoing water temperature sensor issue.

Heat exchanger outgoing temperature sensor issue.

Combustion air temperature sensor issue.

Upper tank temperature sensor issue.

Lower tank temperature sensor issue.

Inlet water temperature thermistor issue.

Modulating solenoid valve signal issue.

Combustion fan issue.

Low flow in recirculation circuit.

The water flow control valve has failed to close during the bath fill function.

Bypass flow servo issue.

PC Board issue.

Solenoid valve circuit issue.

Flame sensing device issue.

Water has been detected at the bottom of the unit.

Scale build-up in the heat exchanger, needs flushing.

Indicates it is time for service/flush.

Indicates a licensed professional performed maintenance or corrected an issue.

Pump activated, but no code is displayed and no operation occurs.

Scale Build-up in Heat Exchanger

Flush the heat exchanger to prevent damage. Treat hard water. Reset LC code after flushing by pressing the On/Off button...

No water flow activated / Unit not firing

Clean inlet water supply filter. Ensure hot and cold water lines are not reversed.

Obstruction in air supply or exhaust.

Ensure approved venting materials are used. Check that nothing is blocking the flue inlet or exhaust.

Heater fails to ignite.

Check gas supply (turned on, gas in tank for propane, bleed air from line). Ensure appliance is properly grounded.

No flame detected after ignition attempt.

Check gas supply (turned on, gas in tank for propane). Check for obstructions in flue outlet.

Thermal fuse activated.

Check for restrictions in air flow around unit and vent terminal. Check gas type.

Outgoing water temperature is too high.

Check for restrictions in air flow around unit and vent terminal.

Electrical grounding issue.

Check all components for electrical short.

Fault with outgoing water temperature thermistor.

Check sensor wiring for damage. Measure the resistance of the sensor. Clean sensor of scale build-up.

Fault with heat exchanger thermistor.

Check sensor wiring for damage. Measure resistance of sensor. Replace sensor if necessary.

Fault with combustion air temperature thermistor.

Check for restrictions in air flow around unit and vent terminal. Check sensor wiring for damage.

Fault with freeze protection thermistor.

Check sensor wiring for damage. Measure resistance of sensor. Replace sensor if necessary.

Fault with inlet water temperature thermistor.

Check sensor wiring for damage. Measure resistance of sensor. Replace sensor if necessary.

Fault with modulating gas solenoid valve signal.

Check modulating gas solenoid valve wiring harness for loose or damaged terminals. Measure resistance of valve coil.

Fault with combustion fan.

Ensure fan will turn freely. Check wiring harness to motor for damaged and/or loose connections.

Low flow detected in recirculation system.

Ensure inlet water filter is clean and free of debris. Ensure parameter setting is correctly set for recirculation mode.

Fault with water flow servo.

Measure the resistance values and voltage of the water flow control. Ensure the harness and connector are not wet.

Fault with bypass flow servo.

Measure the resistance values and voltage of the bypass servo valve. Ensure the harness and connector are not wet.

Fault with PC Board.

Check the connection harness at the connection on the PC board. Replace PC board.

Fault with solenoid valve circuit.

Ensure dip switch on PC board is in the OFF position. Check gas solenoid valves for short circuits or grounding.

Fault with flame sensing device.

Verify flame rod is touching flame when unit fires. Check the flame rod and wire for damage.

Water leak detected.

Turn off water supply and contact licensed professional.

Power interruption during bath fill (Water will not flow when power returns).

Venturi Control.

Venturi Blockage.

Gas Valve Adjustment Limit.

Data Transfer Error.

Gas Valve Adjustment.

Condensate Pump (Accessory).

Exhaust Thermistor.

Freeze Protection Thermistor.

High Exhaust Gas Temperature.

Air supply or exhaust blockage.