Navien NCB-24LSWE, Service Manual

Page: 61 / 144

NCB Service Manual 59 Version 1.0
Section Test points
Colour coding
Readings Remarks
Terminals Wires
High v
o
lta
g
e
Input voltage
CON1 (1,3)
BLUE
BROWN
2P AC 230 V
3.15 A fuse is connected to the
BROWN cable.
CON17
GREEN
YELLOW
1P Earth
Ignition
transformer
CONW1 (2,4) BROWN - BLUE 2P AC 230 V
Input voltage
Circulation
pump
CON25 (2,4) YELLOW - WHITE 2P AC 230 V
3-way valve CON25 (1,5,6)
RED
3P AC 230 V
Space heating: RED + WHITE =
AC 230 V
PURPLE
DHW: RED + PURPLE = AC 230 V
WHITE
Blower (DC-FAN) CONU1 (3-4) BLACK - YELLOW 2P
Max allowable voltage: V
325 DC
Vsp: DC 2.6 V to 5.6 V
Vsp voltage via PWM regulation
Dual venturi
CONW1
(1,6,7)
BLUE
3P AC 230 V
Applicable to 40K only.
OFF(Low load): BLUE, WHITE
ON (High load): BLUE, BROWN
BROWN
WHITE
Flame detector CONK1 (1) BLACK 1P
1to15uA (Combustion)
0uA (Stand-by)
Open the circuit before
measuring.
Low
v
o
lta
g
e
Gas valve CONZ1 (1,2) WHITE - YELLOW 2P DC 24 V
Voltage is applied only when
the valve is operating.
APS1
CONF1
(1,2,4)
RED
3P
RED + BLACK: DC 5 V
RED + BLACK: DC 5 V, constant
WHITE Feedback: WHITE
WHITE + BLACK: DC 0.3 to 3.5 V,
variable
BLACK
APS2
CONF1
(1,3,4)
RED
3P
RED + BLACK: DC 5 V
Feedback: YELLOW
RED + BLACK: DC 5 V, constant
BLACK: DC 0.3 to 3.5
V, variable
YELLOW
BLACK
Panel CON10 (1-9)
RED
9P
RED + BLACK (1,8)
: DC 5 V
BLACK + BLACK (7,8)
: DC 12 V
BLACK + BLACK (9,8)
: DC 24 V
BLACK + BLACK (5,8)
: communication signal voltage
– not to be measured
BLACK + BLACK (6,8)
: communication signal voltage
– not to be measured
BLACK
Water pressure
sensor
CONF1
(5,6,7)
RED
3P variable
DC 0.24 V (0.5bar) to DC 4.93 V
(3.9bar)
BLACK
GREEN
Overheating
sensor
CONF1
(12,14)
BLACK - BLACK 2P DC 24 V
Normal: DC 24 V, Error: 0 V
Flow sensor
CONF1
(8,9,10)
RED
3P Pulse
No pulse is measured.
WHITE
BLACK
DHW
temperature
sensor
CONE1 (3,4) BLUE - BLUE 2P
Resistance by
temperature range
Refer to temperature sensor
data table.
Optional
junction
box
Room
thermostat
COND1
(3,4)
WHITE - WHITE 2P DC 12 V
OPEN: 0 V
SHORT: DC 12 V
Open
thermostat
COND1
(1,2)
RED – RED 2P Not to be measured
Communication pulse signal
Outdoor
temperature
sensor
COND1
(5,6)
BLUE – BLUE 2P
Resistance by
temperature range
Refer to temperature sensor
data table.