Rinnai Water Heater Service Manual 9 100000098 Rev B
Code Definition Remedy
25
Condensate Trap Error
ONLY FOR
CONDENSING MODELS
Condensate container is full.
Check condensate drain for blockage.
Replace condensate trap.
31 Burner Sensor Error
ONLY FOR VB AND
CONDENSING INDOOR
MODELS
Measure resistance of sensor.
Replace sensor.
32 Outgoing Water
Temperature Sensor
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
33 Heat Exchanger Outgoing
Temperature Sensor
Check sensor wiring to be sure it has not been short circuited.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
34 Combustion Air
Temperature Sensor
ONLY FOR INDOOR
NON-CONDENSING
MODELS (EXCEPT
R98LSi)
Check for restrictions in the intake and exhaust system.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Check the fan blade to be sure it is tight on motor shaft and is in good condition.
Replace sensor.
52 Modulating Solenoid
Valve Signal Abnormal
Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
61 Combustion Fan Failure Ensure fan will turn freely.
Check wiring harness to motor for damaged and/or loose connections.
Measure resistance of motor winding.
Check for proper voltage from PC board.
65 Water Flow Control 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.
70 Sensor Harness
Connection
ONLY FOR
CONDENSING MODELS
Check PC board switches (in the bank of 6 switches, #2 should be on for indoor models and off for
outdoor models)
Check the connection harness at the E connection on the PC board. Outdoor models should have
2 orange cables at #7 and 8 positions. Indoor models should not have cables at these positions. If
this is incorrect then replace the sensor harness.
Replace PC board
71 Solenoid Valve Circuit For non-condensing, check wiring harness to all solenoids for damage and/or loose connections.
Measure resistance of each solenoid valve coil.
For condensing, replace PC board.
72 Flame Sensing Device Verify flame rod is touching flame when unit fires.
Check all wiring to flame rod.
Remove flame rod and check for carbon build-up; clean with sand paper or emery cloth.
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.
73 Burner Sensor Circuit
ONLY FOR VB AND
CONDENSING INDOOR
MODELS
Check sensor wiring and PC board to be sure they have not been damaged.
Replace sensor.
LC Scale Build-up in Heat
Exchanger (when
checking maintenance
code history, “00” is
substituted for “LC”)
Flush heat exchanger. Refer to instructions in manual. Hard water must be treated to prevent
scale build up or damage to the heat exchanger.
Replace heat exchanger.
NOTE: The LC code is the only 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.
No
code
Nothing happens when
water flow is activated.
On controller, verify if unit is sensing flow. If not then check the items below. If unit is
sensing flow then check the heat exchanger and outlet thermistors.
Clean inlet water supply filter.
On new installations ensure hot and cold water lines are not reversed.
Check for cold to hot cross over. Isolate circulating system if present. Turn off cold water to the
unit, open pressure relief valve; if water continues to flow, there is bleed over in your plumbing.
Verify you have at least the minimum flow rate required to fire unit.
Verify turbine spins freely.
Measure the resistance of the water flow control sensor.
If the display is blank and clicking is coming from the unit, disconnect the water flow servo motor
(RD, BL, BR, GY, YL). If the display come on then replace the water flow servo motor.
Diagnostic Codes
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