Rinnai REU-KA2530FFUD-US Service Manual page 7

Code Definition
16 Over Temperature
Warning
19 Electrical Grounding
25 Condensate Trap Error
31 Burner Sensor Error
32
Outgoing Water
Temperature Sensor
33 Heat Exchanger Outgoing
Temperature Sensor
41 Outside Temperature
Sensor
51 Inlet Water Temperature
Sensor
52 Modulating Solenoid
Valve Signal Abnormal
57 Burner
(Bi-Metal sensors /
Thermal Fuse Harness)
58 Secondary Heat
Exchanger
61 Combustion Fan Failure
65 Water Flow Control
70 Sensor Harness
Connection
71 Solenoid Valve Circuit
72 Flame Sensing Device
Condensing Water Heater Service Manual
Diagnostic Codes
Remedy
Check for restrictions in the intake and exhaust system.
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.
Check all components for electrical short.
Condensate container is full.
Check condensate drain 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 sensor wiring to be sure it has not been short circuited.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
Check for continuity through bi-metal sensors located at top of heat exchanger at white plastic
connector containing red an white wires.
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.
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.
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.
Check PC board switches (in the bank of 6 switches, #2 should be on for indoor models and off for
outdoor models on KA series units only)
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
Replace 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 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.
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