Rinnai RL75i Installation And Operation Manual page 38

Code Definition
19 Electrical Grounding
Outgoing Water
32
Temperature Sensor
Heat Exchanger Outgoing
33
Temperature Sensor
Combustion Air
34
Temperature Sensor
Outside temperature
41 thermistor (outdoor
models only)
Inlet water temperature
51
thermistor
Modulating Solenoid Valve
52
Signal
61 Combustion Fan
65 Water Flow Control
70 PC Board
71 Solenoid Valve Circuit
72 Flame Sensing Device
79 Water Leak Detected
Scale Build-up in Heat
LC #
Exchanger (when checking
(LC0,
maintenance code history,
LC1,
"00" is substituted for
LC2,...)
"LC")
Maintenance has been
FF
performed
No Nothing happens when
code water flow is activated.
38
Remedy
Check all components for electrical short.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
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.
Check sensor wiring for damage.
Measure resistance of sensor.
licensed
Clean sensor of scale build-up.
professional
Replace sensor.
only
Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
Ensure fan will turn freely.
Check wiring harness to motor for damaged and/or loose connections.
Measure resistance of motor winding.
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 licensed professional to service
the appliance.
Check PC board DIP switches for correct position.
Check the connection harness at the connection on the PC board.
Replace PC board.
Replace the PC Board.
Replace PC Board
Water has been detected at the bottom of the unit. Turn off water supply. Check all plumbing
internally for leakage.
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.
Please call Rinnai technical department.
Indicates a licensed professional performed maintenance or corrected an issue.
Clean inlet water supply filter.
On new installations ensure hot and cold water lines are not reversed.
Verify you have at least the minimum flow rate required to fire unit.
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.
licensed Verify turbine spins freely.
professional Measure the resistance of the water flow control sensor.
only If the display is blank and clicking is coming from the unit, disconnect the water flow servo
motor (GY, BR, O, W, P, BL, R). If the display comes on then replace the water flow servo
motor.
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