22
7
Diagrams
Figure 7-1 Ladder Diagram
ModBus Instructions
JUNCTION BOX
TERMINAL STRIP
120V SUPPLY "L"
TERMINAL STRIP
120V SUPPLY "N"
120VAC
NEUTRAL
INTEGRATED CONTROL
ON/OFF
SWITCH
F2
3.15 A
F4
5.0 A
SYSTEM PUMP
RELAY
BOILER PUMP
RELAY
DHW PUMP
RELAY
X1-1
X1-2
X1-4
X1-8
X2-4
SMALL BLOWER
RELAY
LARGE BLOWER
RELAY
SMALL GAS
VALVE RELAY
LARGE GAS
VALVE RELAY
X1-6
2
-
0
1
X
1
-
0
1
X
X10-3
SMALL GAS
VALVE RELAY
LARGE GAS
VALVE RELAY
X10-6
X10-5
X10-4
GAS
VALVE
(LARGE)
GAS
VALVE
(SMALL)
TERMINAL STRIP
SYSTEM PUMP
CONTACTOR
BOLIER PUMP
CONTACTOR
DHW PUMP
CONTACTOR
SMALL BLOWER
RELAY
LARGE BLOWER
RELAY
SMALL BLOWER
LARGE BLOWER
X6-10
X13-4
X6-1
X2-5
2
1
3
2
1
3
MODBUS
X1-1
X1-2
X1-3
FLUE DAMPER
TRANSFORMER
M
1
2
3
24V
TRANSFORMER
FLUE DAMPER
X6-3
X1-12
X1-3
LWCO
BOARD
TEST
SWITCH
LWCO
PROBE
LWCO RESET
J3-6
J3-3
J2-1
J2-2
J3-5
J3-2
J3-4
X6-5
X6-15
X6-12
X13-1
X6-6
X3-3
X3-4
X3-1
X3-2
X6-11
X6-2
X6-14
INTEGRATED
CONTROL
GPS1
GPS2
GPS3
BLOWER PROVING
SWITCH (LARGE)
BLOWER PROVING
SWITCH (SMALL)
BLOCKED FLUE
SWITCH
BLOCKED DRAIN
SWITCH
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
ALARM
CONTACTS
RUN-TIME
CONTACTS
TANK
THERMOSTAT
LOUVER
PROVING
24 VAC LOUVER
RELAY COIL
AUX
SWITCH 1
AUX
SWITCH 2
ENABLE
R
W
SMALL
CONNECTION BOARD
CN1-4
CN1-5
CN1-6
CN1-12
CN1-10
X6-13
X6-4
CN1-11
CN1-9
CN1-8
CN1-7
CN1-1
CN1-2
CN1-3
HIGH LIMIT
SWITCH
X1-3
X1-7
X1-10
X2-5
FLAME
SENSE 2
FLAME
SENSE 1
SPARK
GENERATOR
SPARK
ROD
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
SHIELD
SHIELD
A
B
MODBUS
OPTION
+
-
-
+
RATE
OUT
BOILER
PUMP OUT
SYSTEM RETURN
SENSOR
SYSTEM SUPPLY
SENSOR
0-10V
0-10V
TANK
SENSOR
OUTDOOR
SENSOR
+
+
-
-
0-10V
0-10V
BMS
IN
SYSTEM
PUMP IN
SHIELD
SHIELD
A
B
CASCADE
LARGE
CONNECTION BOARD
CN6-1
CN3-6
CN3-7
CN3-14
CN3-13
CN3-11
CN3-9
CN3-8
CN3-1
CN3-2
CN3-3
CN3-4
CN6-2
CN6-3
CN3-10
CN3-12
MODBUS
BOARD
X4-1
X4-2
X4-3
X6-3
X6-1
X6-2
X8-20
X8-10
X7-8
X8-13
X8-14
X8-12
INTEGRATED
CONTROL
X8-5
X8-15
X7-7
X8-11
X8-6
X8-16
X8-7
X8-17
X8-1
-T
-T
-T
-T
-T
-T
-T
-T
-T
INLET SENSOR
OUTLET SENSOR (S9)
OUTLET SENSOR (S1)
FLUE SENSOR
FLUE SENSOR (S10)
PRE-MIX SENSOR 1 (S11)
PRE-MIX SENSOR 1 (S13)
PRE-MIX SENSOR 2 (S12)
PRE-MIX SENSOR 2 (S14)
X8-3
X8-8
X8-2
X8-4
X8-9
X7-1
X7-5
X7-2
X7-6
GROUND
X6-18
X6-9
X6-17
X6-8
X13-2
X13-3
1
2
4
5
1
2
4
5
SMALL BLOWER
LARGE BLOWER
1.5A EACH MAX
X11
CN3
CN1
DU941
LCD
DISPLAY
X4
RIBBON CABLE
X5-1
X5-7
X5-2
X5-8
X5-3
X5-9
X5-4
X5-10
X5-5
X5-41
X5-6
X5-12
BOX DEPICTS
OPTIONAL ITEMS
BOX DEPICTS
DUAL SENSOR
SINGLE HOUSING
HIGH VOLTAGE
LOW VOLTAGE
120 VAC
Notes:
1. All wiring must be installed in accordance with: local, state, provincial and national code requirements per either N.E.C. in USA or
C.S.A. in Canada.
2. If any original equipment wire as supplied with the appliance must be replaced, it must be replaced with wire having same wire gauge
(AWG) and rated for a minimum of 105°C. Exceptions: Replacement high voltage spark lead and ribbon cables must be purchased
from the factory. Use of a non-approved spark lead or ribbon cables can lead to operational problems which could result in
non-repairable damage to the integrated controller or other components.
3. Actual connector block locations may vary from those shown on diagrams. Refer to actual components for proper connector block
locations when using diagrams to troubleshoot unit.
LADDER DIAGRAM
LBL20182 REV A
USB
INTERFACE
"X5"
BLOCK WIRING
IS MODEL
DEPENDANT