Noritz NR501-OD Service Manual page 27

<NRC711 (-DV, -OD)>
WIRING DIAGRAM
Circuit Board Block Diagram
HOT
FREEZE PREVENTION
HEATER
DC170V
DC12V
DC15V
15V POWER CIRCUIT
GND
HIGH LIMIT
SWITCH
VARISTOR
DC170V
POWER
COMBUSTION FAN
CONTROLLER
RELAY 2
PRIMARY
C A
SECONDARY
B
RELAY 1
RELAY 2
WATER LEVEL ELECTRODE DETECTION CIRCUIT
FLUSH CONNECTOR
THERMAL FUSE
SOLENOID VALVE 0
SOLENOID VALVE 1
SOLENOID VALVE 2
SOLENOID VALVE 3
COLOR CODING
W : White BK : Black
: Gray
R : Red GY
NEUTRAL
10A(FUSE)
VARISTOR
RELAY 1
VARISTOR ARRESTER
EARTH
IGNITER E
IG
GND
WATER FLOW SENSOR
WATER SERVO - MAIN
GAS PROPORTIONING VALVE
POWER CONTROL CIRCUIT
FLAME DETECTING CIRCUIT
D
FLAME ROD EARTH
GAS SOLENOID VALVE
DRIVING CIRCUIT
27
O
BR : Brown Y : Yellow
V : Violet G
BL : Blue
Minimum Manifold Pressure Set Button
FAN CONTROL
OUTPUT FAN
PULSE
CONTROL
FAN ROTATION
CIRCUIT
SPEED INPUT
FAN CURRENT
VALUE INPUT
Sub-CPU
SUB
CONTROL
UNIT
THERMISTOR
- AIR
THERMISTOR
- HOT WATER
THERMISTOR
- COLD WATER
THERMISTOR
- HEAT EXCHANGER
THERMISTOR
- EXHAUST
< -DV MODEL ONLY >
5V POWER CIRCUIT
GND
A
B
C
D
E