Rinnai RU80i Installation And Operation Manual page 38

Code Defini on
19 Electrical Grounding
25 Condensate Trap is full
31 Burner Sensor
Outgoing Water
32
Temperature Sensor
Heat Exchanger Outgoing
33
Temperature Sensor
Outside Temperature
41
Sensor
Inlet Water Temperature
51
Sensor
Modula ng Solenoid Valve
52
Signal
57 Burner
58 Secondary heat exchanger
61 Combus on Fan
65 Water Flow Control
70 PC Board
71 Solenoid Valve Circuit
72 Flame Sensing Device
73 Burner Sensor Circuit
79 Water Leakage Detected
Scale Build‐up in Heat
LC #
Exchanger (when checking
(LC0,
maintenance code history,
LC1,
"00" is subs tuted for
LC2,...)
"LC")
Maintenance has been
FF
performed
No Nothing happens when
code water flow is ac vated.
38
Remedy
licensed
professional Check all components for electrical short.
only
Check condensate trap and drain line for blockage.
Replace condensate trap.
Measure resistance of sensor.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build‐up.
Replace sensor.
Check modula ng gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
Contact a licensed professional.
There is scale build up in the secondary heat exchanger and it needs to be flushed to prevent
damage. Refer to the flushing instruc ons in the manual. Hard water must be treated to
prevent scale build up or damage to the heat exchanger.
licensed
Ensure fan will turn freely.
professional
Check wiring harness to motor for damaged and/or loose connec ons.
only
Measure resistance of motor winding.
The water flow control valve has failed to close during the bath fill func on. Immediately turn
off the water and discon nue the bath fill func on. Contact a licensed professional to service
the appliance.
Check PC board DIP switches for correct posi on.
Check the connec on harness at the connec on on the PC board.
Replace PC board.
Replace the PC Board.
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.
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.
Check sensor wiring and PC board to be sure that they have not been damaged.
Replace sensor.
Turn off water supply and contact licensed professional.
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 instruc ons 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 un l the heat exchanger can be flushed, push the On/
Off bu on on the temperature controller 5 mes. 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 installa ons 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 circula ng system if present. Turn off cold water to the
unit, open pressure relief valve; if water con nues 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 replace the water flow servo motor.
KB Series Manual