Navien NHB-055, Service Manual

Page: 64 / 147

64 NHB Service Manual Version 1.0
Point Function CN No. Wire Color Normal Value Check
A
Exhaust Thermistor
CN13
1-2
BLUE-BLUE DC 0~5V Voltage changes according to temperature.
Heating Return
Temperature Sensor
CN13
5-6
BLUE-BLUE DC 0~5V Voltage changes according to temperature.
HEATING Supply
Temperature Sensor
CN13
7-8
BLUE-BLUE DC 0~5V Voltage changes according to temperature.
High Temperature Limit
Switch
CN13
11-12
BLACK-BLACK DC 0V Normally Shorted. Confirm RMS voltage.
B Outdoor Thermostat CN11 BLUE-BLUE DC 0~5V Voltage changes according to temperature.
D Water Pressure Sensor
CN22
1-2
RED- -BLACK DC 0~5V
E APS
CN6
1-2
RED-BLACK DC 5V Confirm steady voltage.
CN6
2-4
WHITE-BLACK DC 0.3~4.5V
Voltage changes according to the APS
operation.
F
Flame Rod
CN19
1
BLACK DC 10uA
Measure the current when the burner is
operating.
Ground Wire
CN19
2
GREEN /
YELLOW
Check for properly grounded wire.
G Gas Valve
CN16
1-2
WHITE-YELLOW DC 22~24V
Confirm voltage as the Main Gas Valve 1 is
operating.
CN16
1-3
WHITE-RED DC 22~24V
Confirm voltage as the Main Gas Valve 2 is
operating.
H Dual Venturi
CN15
1-2
BROWN-WHITE
ON : AC 95~120V
OFF : 0V
Confirm voltage relative to operation.
CN15
2-5
WHITE-BLUE
ON : AC 95~120V
OFF : 0V
I Power Input
CN1
1-2
WHITE-BLACK AC 97~138V
Confirm appropriate power source.
Confirm the FUSE.
Confirm the circuit breaker.
J Igniter
CN17
1-2
BLUE-BROWN
ON : AC 97~138V
OFF : 0V
Confirm voltage when the unit is igniting.
K Fan Motor
CN8
4-7
BLACK-RED DC 127~184V Confirm steady voltage.
CN8
2-4
BLACK-YELLOW DC 15V Confirm steady voltage.
CN8
3-4
BLACK-ORANGE DC 0~7.5V Voltage changes relative to fan operation.
CN8
1-4
BLACK-WHITE 0~6,700rpm Check PULSE.