50

WARNING

DO NOT adjust any dipswitch settings on PC board except dip switch number 1, if required, for vent

length or unless instructed to do so.

RELAY 1
IG
FROSTSENSING
SWITCH
ANTI-FROSTHEATER
IGNITION
COMBUSTION
FAN
3A(FUSE)
HOT NEUTRAL
VARISTOR
DC12.6V
SOLENOID
DRIVING
CIRCUIT
CPU
CENTRAL
PROCESSING
UNIT
FAN
REMOTE
CONTROLLER
POV
FAN
CONTROL
CIRCUIT
BY-PASSFLOW
CONTROLDEVI CE
CIRCUIT
THERMALFUSE
OVERHEAT
SWITCH
MODULATING
SOLENOID
VALVE
DC40V
DC5V
A B C SG
SWITCHING
POWERSUPPLY
THERMISTOR
CIRCUIT
B
SG
RELAY 1
A
WATER FLOW
SENSOR
CIRCUIT
WATER FLOW
CONTROLDEVI CE
CIRCUIT
A
SG
A
SG
SG
A
QS
SG
FR
FLAME
DETECTING
CIRCUIT
FLAMEROD
GND
SG
A
REMOTE
CONTROLLER
CIRCUIT
A B
E
PG
ABC
SG
SG
B
VARISTOR
ARRESTER
GND
SG
WATERFL OW
SENSOR
WATER FLOW
CONTROLDEVICE
BY-PASSFLOW
CONTROLDEVICE
M
M
DC12V
DC170V
D
E
PG
SV3
SV2
SV1
SV0
RELAY
DRIVING
CIRCUIT
D
BY-PASSSERVOMODEL ONLY
OUTGOING WATER
THERMISTOR
HEATEXCHANGER
THERMISTOR
AIRTEMPERATURE
THERMISTOR
INDOORMODELONLY
MODULATING
VALVEPOWER
CONTROL
CIRCUIT

Figure 41. Ladder Diagram.