Navien NFC-175 Service Manual page 51

Point Function
Exhaust Thermistor
Heating Return
Temperature Sensor
Heating Supply
A
Temperature Sensor
High
Temperature Limit Switch
APS
B Outdoor Thermostat
Flame Rod
C
Ground Wire
Water Pressure Sensor
D
Gas Valve
Dual Venturi
E
Igniter
F Power Input
G Fan Motor
Version 1.0
CN No. Wire Color
CNJ1 1-2 BLUE-BLUE
CNJ1 5-6 BLUE-BLUE
CNJ1 7-8 BLUE-BLUE
CNJ1 13-14 BLACK-BLACK
CNJ1 9-10-12 RED-BLACK-WHITE
CNT3 BLUE-BLUE
CNI1 2 BLACK
CNI1 1 GREEN / YELLOW
CNG1 4-5-6 RED-BLACK
CNG1 2-3 WHITE-YELLOW
CNG1 1-2 WHITE-RED
CNO1 1-2-4 BROWN-BLACK-BLUE
CNO1 5-7 BLUE-BROWN
CON1 1-2 WHITE-BLACK
CNR1 4-7 BLACK-RED
CNR1 2-4 BLACK-YELLOW
CNR1 3-4 BLACK-ORANGE
CNR1 1-4 BLACK-WHITE
Normal Value
Voltage changes according to
DC 0-5V
temperature
Voltage changes according to
DC 0-5V
temperature
Voltage changes according to
DC 0-5V
temperature
DC 0V Normally Shorted. Confirm RMS voltage
DC 5V
Voltage changes according to
DC 0-5V
temperature
Measure the current when the burner is
DC 10uA
operating.
Check for properly grounded wire
DC 0-5V
Confirm voltage as the Main Gas Valve 1
DC 22-24V
is operating.
Confirm voltage as the Main Gas Valve 2
DC 22-24V
is operating.
ON : AC 95-120V
Confirm voltage relative to operation
OFF : 0V
ON : AC 97-138V Confirm voltage when the unit is
OFF : 0V igniting.
Confirm appropriate power source.
AC 97-138V Confirm the fuse.
Confirm the circuit breaker
DC 127-184V Confirm steady voltage
DC 15V Confirm steady voltage
Voltage changes relative to fan
DC 0-7.5V
operation
0-6,700rpm Check pulse
Check
NFC Service Manual 51