Ladder Diagram - Navien NHB Series Installation & Operation Manual

12.3 Ladder Diagram

AC Gas Valve
(NFB-399C)
APS
Exhaust
Thermistor 1
Heating Supply
Thermistor
System Supply
Thermistor
Outdoor
Thermistor
Linear
Trans
AC 24V
O O
N N
1 2 3 4 5 6 1 2 3
Dip Switch
Zone1 Thermostat
Zone2 Thermostat
Zone3 Thermostat
Zone4 Thermostat(DHW)
Manual
Auto
AC INPUT(AC 120V)
LIVE NEUTRAL
EMI
FILTER
PWM
Primary Primary
SMPS
Secondary
WPS
Fan
Hall Sensor
Exhaust
Thermistor 2
Heating Return
Thermistor
System Return
Thermistor
DHW Tank
Thermistor
4 5 6 7 8 LWCO
R,W,C
R,W,C
R,W,C
R,W,C
Flow Switch
Dual Venturi
Relay 5
Relay 6
Igniter
Relay 7
Blower
Speed Control
DC24V
Relay coil
1~11
DC12V
DC9V
DC5V
MCU 1
VDC Output
VDC Input
Communication
Communication
AC INPUT(AC 120 V)
LIVE
Terminal Board
Relay 1
10A
Boiler Pump
Relay 2
10A
ZONE1 Pump
Relay 3
10A
ZONE2 Pump
Relay 4
10A
ZONE3 Pump
Flame Rod
H.T.L(HE)
H.T.L(BH)
WD-PSS
DC Gas Valve
(NFB-301C)
Interface
UART
Interface
CASCADE
Graphic Panel
(RS-485)
Terminal Board
Relay 8
Output
Air Handler
Relay 9
Output
DHW Priority
Relay 10
Boiler State Output
Relay 11
Boiler Error Output
NEUTRAL
MCU 2
Appendixes 117