56
Error Codes and Checkpoints (In the case of optional remote controller connection)
<NR98 (-SV,-OD,-DVC) / NC199 (-OD,-DVC) / N-0751M (-OD,-DV,-DVC)
NR111 (-SV,-OD,-DV) / NC250 (-SV,-DV)-ASME / N-0931M (-OD,-DV) /
NC380-SV-ASME / N-1321M-ASME >
*In a quick connect multi-system, "F##"(except F76) indicates an error code from the secondary unit (unit without a remote).
Note 1) This error code is not mentioned in the owchart.
Note 1)
Note 1)
Note 1)
Note 1)
Flame rod circuit abnormality
(Detection of ame when no
ame is present)
Check for abnormal combustion.
Check ue for blockage or obstruction.
Check for abnormal combustion.
Check ue for blockage or obstruction.
Check for proper connection of quick connect cord.
Check connection from remote controller to circuit board.
Check remote controller and circuit board for damage.
Check for proper setting of maintenance writers on circuit board.
Check the circuit board (microcomputer) for damage. Check the
Dip switch. Check the "Control switch connector"
(ex. high elevation connector etc.).
Combustion abnormality
(Unit shuts o)
Multi-system communication
error
Remote controller transmission
abnormality
Circuit board setting abnormality
(High elevation connector,
Dip switch, etc)
Combustion abnormality
(Warning indication)
760
F76
(F) 90
(F) 73
Check that the main ow control valve is functioning ( ).
Check for improper connection of the valve.
Check for damage to the gas solenoid valve drive circuit on the
circuit board.
Measure the resistance through the inlet thermistor ( ).
Check for an open or short circuit.
Check for improper connection of inlet thermistor.
Measure the resistance through the outlet thermistor ( ).
Check for proportional gas valve trouble ( ).
Check for abnormal combustion.
Check ue for blockage or obstruction.
Diagnosis Point (Trouble Point)
Flame rod does not detect ame
(Flame fault detection)
Outlet thermistor abnormality
Main ow control valve
abnormality
Circuit board abnormality
Heat exchanger thermistor
abnormality
Gas solenoid valve drive circuit
abnormality
(F) 72
(F) 71
(F) 70
(F) 66
Fan motor abnormality
(F) 61
(F) 65
(F) 33
Circuit board failure
Air inlet thermistor abnormality
High limit switch triggered
Abnormally high output
temperature
Overheat Prevention Device
(Thermal Fuse) triggered
Inlet thermistor abnormality
(F) 32
(F) 31
(F) 30
(F) 16
(F) 14
Ignition failure
(Initial ame fault detection)
Combustion abnormality
(BTU Drop)
(Unit Continues Working)
(F) 12
(F) 11
Display
Description
Measure the current from the ame rod when there is no ame
( ). Check for a ground fault.
Check the gas supply piping and pressure. Check for igniter
spark ( ). Check gas solenoid valves ( ).
Check ame rod ( ). Check ground, paying special attention to
the ground connection to the circuit board.
Check for accidental extinction of the ame. Check for abnormal
combustion. Check gas solenoid valves. Check ame rod ( ).
Check ground, especially on circuit board.
Check for melting or damage to the thermal fuse ( ).
Check for improper connection of thermal fuse.
Check if high limit switch is triggered ( ).
Check for improper connection of high limit switch.
Measure the resistance through the air inlet thermistor ( ).
Check for an open or short circuit.
Check for improper connection of air inlet thermistor.
Measure the resistance through the heat exchanger thermistor
( ). Check for an open or short circuit.
Check for improper connection of heat exchanger thermistor.
Check that the fan is rotating and check the pulse frequency from
the fan rotational frequency sensor ( ). Check for improper
connection of the fan. Check voltage from circuit board.
16
11
10
9
29
18
16
13
12
14
15
To reset this error code, the power needs to
be disconnected and then reconnected.
To reset this error code, the power needs to
be disconnected and then reconnected.
To reset this error code, the power needs to
be disconnected and then reconnected.
Remarks
Measure the resistance through the outlet thermistor ( ).
Check for an open or short circuit.
Check for improper connection of outlet thermistor.
(F) 59
Heat exchanger ow
abnormality
Check for scale build-up in heat exchanger. Check for abnormal
combustion. Check ue for blockage or obstruction. Check that
ame ignites all across the burner.
Bypass ow control valve
abnormality
Check that the main water control valve is functioning ( ).
Check for improper connection of the valve.
To reset this error code, the power needs to
be disconnected and then reconnected.
To reset this error code, the power needs to
be disconnected and then reconnected.
To reset this error code, the power needs to
be disconnected and then reconnected.
To reset this error code, the power needs to
be disconnected and then reconnected.
Check for abnormal combustion. Check ue for blockage or
obstruction. Check that ame ignites all across the burner.
Combustion abnormality
(Unit shuts o)
15
5
6
7
2
3
8
6
1
(F) 99
(F) 20
(F) 10
(F) 21
Pressure switch triggered Check pressure switch. Check fan motor. Check ue for blockage
or obstruction. Check for abnormal combustion.
For NC380-SV-ASME/N-1321M-ASME only
(F) 41
Flow Sensor Abnormality
Check ow sensor for debris and/or damage.
(F) 56
Multi-System CCP Valve
Abnormality
Check for an obstruction in the CCP valve. Check for improper wiring
connection of multi-system wiring.
For NC380-SV-ASME/N-1321M-ASME only
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