Rinnai Error Codes

Troubleshoot Your Tankless Water Heater Error Code


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No Burner Operation During Freeze Protection Mode

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Schedule Service Call with Silva Mechancial

Power Interruption During Bath Fill (Water will not flow when power returns).

  • Turn off all hot water taps. Press ON/OFF twice.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Schedule Service Call with Silva Mechancial

By-Pass Flow Control

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Measure resistance values of the by-pass flow control.
  • Replace By-Pass flow control device.

Air Supply or Exhaust Blockage

  • Check that nothing is blocking the flue inlet or exhaust.
  • Check all vent components for proper connections.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure approved venting materials are being used.
  • Ensure vent length is within limits.
  • Verify dip switches are set properly.
  • Check fan for blockage.

No Ignition (Heating Not Turning On)

  • Check that the gas is turned on at the water heater, gas meter, or cylinder.
  • If the system is propane, make sure that gas is in the tank.
  • Ensure appliance is properly grounded.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure gas type and pressure is correct.
  • Ensure gas line, meter, and/or regulator is sized properly.
  • Bleed all air from gas lines.
  • Verify dip switches are set properly.
  • Disconnect EZConnect™ or MSA controls to isolate the problem.
  • Ensure igniter is operational.
  • Check igniter wiring harness for damage.
  • Check gas solenoid valves for open or short circuits.
  • Remove burner cover and ensure all burners are properly seated.
  • Remove burner plate and inspect burner surface for condensation or debris.
  • Check the ground wire for the PC board.

Flame Failure - No Flame

  • Check that the gas is turned on at the water heater, gas meter, or cylinder.
  • Check for obstructions in the flue outlet.
  • If the system is propane, make sure that gas is in the tank.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure gas line, meter, and/or regulator is sized properly.
  • Ensure gas type and pressure is correct.
  • Bleed all air from gas lines.
  • Ensure proper venting material was installed.
  • Ensure condensation collar was installed properly.
  • Ensure vent length is within limits.
  • Verify dip switches are set properly.
  • Ensure appliance is properly grounded.
  • Disconnect keypad.
  • Disconnect EZConnect™ or MSA controls to isolate the problem.
  • Check power supply for loose connections.
  • Check power supply for proper voltage and voltage drops.
  • Ensure flame rod wire is connected.
  • Check flame rod for carbon build-up.
  • Disconnect and reconnect all wiring harnesses on unit and PC board.
  • Check for DC shorts at components.
  • Check gas solenoid valves for open or short circuits.
  • Remove burner plate and inspect burner surface for condensation or debris.

Thermal Fuse has Activated

  • Check for restrictions in air flow around unit and vent terminal.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure SW 5 in DIPSW 2 is in the off position.
  • Check gas type of unit and ensure it matches gas type being used.
  • Check for low water flow in a circulating system causing short-cycling.
  • Ensure dip switches are set to the proper position.
  • Check for foreign materials in combustion chamber and/or exhaust piping.
  • Check heat exchanger for cracks and/or separations.
  • Check heat exchanger surface for hot spots which indicate blockage due to scale build-up. Refer to instructions in manual for flushing heat exchanger.
  • Hard water must be treated to prevent scale build up or damage to the heat exchanger.
  • Measure resistance of safety circuit.
  • Ensure high fire and low fire manifold pressure is correct.
  • Check for improper conversion of product.

Venturi Control

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure the Venturi motor is operating correctly.
  • Replace gas valve assembly.
  • Clear diagnostic code by resetting the main power supply to the water heater.

Over Temperature Warning (Safety Shutdown Because Unit is Too Hot)

  • Check for restrictions in air flow around unit and vent terminal.
  • Confirm fan motor is functioning correctly.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check for low water flow in a circulating system causing short-cycling.
  • Check for foreign materials in combustion chamber and/or exhaust piping.
  • Check for blockage in the heat exchanger.
  • Replace the gas valve assembly.

Venturi Blockage

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure Venturi isn’t blocked.
  • Call Rinnai technical department.

Electrical Grounding

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check all components for electrical short.

Data Transfer Error

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • If the PCB has been replaced, ensure the data transfer process has been completed.

Condensate Pump (Accessory) Condense Trap is Full

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Confirm wire connections and harness are good.
  • Ensure condensate reservoir is empty and condensate pump is operating.

Burner Sensor Error

  • Measure resistance of sensor.
  • Replace sensor.

Outgoing Water Temperature Sensor Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Replace sensor.

Heat Exchanger Outgoing Temperature Sensor Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Replace sensor.

Combustion Air Temperature Sensor Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check for restrictions in air flow around unit and vent terminal.
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Ensure fan blade is tight on motor shaft and is in good condition.
  • Replace sensor.

Exhaust Thermistor CO Sensor

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Replace sensor.

Outside Temperature Thermistor Freeze Protection Sensor

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Replace sensor.

Inlet Water Temperature Thermistor (Sensor)

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring for damage.
  • Measure resistance of sensor.
  • Clean sensor of scale build-up.
  • Replace sensor.

Inlet Water Temperature Thermistor (Sensor)

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
  • Measure resistance of valve coil.

High Exhaust Gas Temperature

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure Heat Exchanger fins are clean and not blocked.
  • Confirm inlet water temperature is not too high.
  • Clear diagnostic code by resetting the main power supply to the water heater.

Burner Overheat Bi-Metal Switch

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting

Secondary Heat Exchanger Sensor

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • There is scale build up in the secondary heat exchanger and it needs to be flushed to prevent damage. Refer to the flushing instructions in the manual. Hard water must be treated to prevent scale build up or damage to the heat exchanger.

Combustion Fan Motor Failure

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure fan will turn freely.
  • Check wiring harness to motor for damaged and/or loose connections.
  • Measure resistance of motor winding.

Recirculation Low Flow Circulation Flow Rate dropped below 1.3 GPM

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure bypass plug is removed and bypass filter is installed. (Crossover Mode)
  • Ensure both the inlet water filter and bypass filter are clean and free of debris.
  • Ensure Parameter setting are correctly set for recirculation mode.
  • Ensure Pump supply voltage.
  • Ensure air is removed from the recirculation line.

Water Flow Control Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • The water flow control valve has failed to close during the bath fill function. Immediately turn off the water and discontinue the bath fill function. Contact a state qualified or licensed contractor to service the appliance.

PC Board

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check PC board DIP switches for correct position.
  • Check the connection harness at the connection on the PC board.
  • Replace PC board.

Solenoid Valve Circuit Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Replace PC board.

Flame Sensing Device Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Ensure flame rod is touching flame when unit fires.
  • Check all wiring to flame rod for damage.
  • Remove flame rod and check for carbon build-up; clean with sand paper.
  • Check inside burner chamber for any foreign material blocking flame at flame rod.
  • Measure micro amp output of sensor circuit with flame present.
  • Replace flame rod.

Flame Sensing Device Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Check sensor wiring and PC board for damage.
  • Replace sensor.

Flame Sensing Device Fault

  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Water has been detected at the bottom of the unit. Turn off water supply.
  • Check all plumbing internally for leakage.

Scale Build-up in Heat Exchanger (when checking maintenance code history, “00” is substituted for “LC”)

NOTE: The LC code is the only error code that will allow the unit to keep running. The display will alternate between the LC code and the temperature setting. The controller will continue to beep. The LC code will reset if power is turned off and then on.

  • Flush heat exchanger. Refer to instructions in manual.
  • Replace heat exchanger.
  • LC0-LC9 indicates that there is scale build up in the heat exchanger and that the heat exchanger needs to be flushed to prevent damage. Refer to the flushing instructions in the manual. Hard water must be treated to prevent scale build up or damage to the heat exchanger.
  • To operate the water heater temporarily until the heat exchanger can be flushed, push the On/Off button on the temperature controller 5 times. Repeated LC codes will eventually lockout the water heater.
  • For you safety and the health of your equipment, Call or Contact Totally Tankless for further troubleshooting
  • Water has been detected at the bottom of the unit. Turn off water supply.
  • Check all plumbing internally for leakage.

(SS) Service Soon (Flush Heat Exchanger)

  • SS is a time-based service indicator set during installation.
  • See section “3.12 Parameter Settings” for additional details on setting and changing the SS indicator.
  • SS indicates that it is time for service. The heat exchanger should be flushed to prevent damage (refer to section Flushing the Heat Exchanger for more information).
  • Hard water must be treated to prevent scale build-up or damage to the heat exchanger.
  • To reset the SS code, push the On/Off button on the temperature controller 5 times in 5 seconds.

Maintenance Has Been Performed

  • Indicates a licensed professional performed maintenance or corrected an issue

Maintenance Has Been Performed

  • Clean inlet water supply filter.
  • On new installations ensure hot and cold water lines are not reversed.
  • Check for bleed over. Isolate unit from building by turning off cold water line to building.
  • Isolate the circulating system if present. Open your pressure relief valve; if water is flowing, there is bleed over in your plumbing.
  • Ensure you have at least the minimum flow rate required to fire unit.
  • Ensure turbine spins freely.
  • Measure the resistance of the water flow control sensor.
  • Check for DC shorts at components.