Noritz NRC661-DV, Service Manual, Page: 26 / 78

Minimum Manifold Pressure Set Button
DOWN But
ton
UP
Button
Y
Circuit Board Block Diagram
HOT NEUTRAL
10A(FUSE)
VARISTOR
VARISTOR ARRESTER
EARTH
VARISTOR
FREEZE PREVENTION
HEATER
DC140V
DC12V
DC140V
RELAY 1
RELAY 2
RELAY 1
RELAY 2
DC15V
CONTROLLER
A C
B
POWER
PRIMARY
SECONDARY
COMBUSTION FAN
E
D
IG
15V POWER CIRCUIT
GND
GND
GND
WATER FLOW SENSOR
WATER SERVO - MAIN
HIGH LIMIT
SWITCH
SOLENOID VALVE 0
SOLENOID VALVE 1
SOLENOID VALVE 2
SOLENOID VALVE 3
IGNITER
POWER CONTROL CIRCUIT
GAS PROPORTIONING VALVE
FLAME DETECTING CIRCUIT
FLAME ROD EARTH
WATER LEVEL ELECTRODE DETECTION CIRCUIT
THERMAL FUSE
5V POWER CIRCUIT
DRIVING CIRCUIT
GAS SOLENOID VALVE
CPU CENTRAL PROCESSING UNIT
A
B
C
D
E
FAN CONTROL
OUTPUT
FAN ROTATION
SPEED INPUT
FAN CURRENT
VALUE INPUT
THERMISTOR
- AIR
THERMISTOR
- HOT WATER
THERMISTOR
- COLD WATER
THERMISTOR
- HEAT EXCHANGER
THERMISTOR
- EXHAUST
< -DV MODEL ONLY >
FAN
PULSE
CONTROL
CIRCUIT
Sub-CPU
SUB
CONTROL
UNIT
26
<NRC661 (-DV/-OD)>