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110327-02 - 7/20
ALTA
Installation, Operating & Service Instructions
20
Internal Wiring Diagrams
Wiring Legend
24VAC
Earth
Ground
Gas Valve
Heat T’stat
Boiler Flow
Switch
Factory Wire Harness
Field wiring
Connector
Screw Terminal
120VAC/60Hz/1Ph
(Line Voltage)
Combustion
Blower
Internal
Overcurrent
Protection
Thermal
Fuse
Air Proving
Switch
N
PCB Trace/Components
3-Way Valve
5W, .05A
L
P1-2
P1-8
X1-5
Fuse T5.0A
(slow blow)
Fuse T1.0A
(slow blow)
Fuse T0.5A
(slow blow)
Jumper (Std)
Jumper (Std)
LWCO
External Limit
(if used)
P3-3
P3-4
Ext.
Limit
Ext.
Limit
OR
P2-4
P3-1
P3-2
LWCO Power
(If Used)
1
2
OR
X1-8
X1-10
X1-9
X2-2
X2-1
Pump Outlet B
Boiler Pump
2.0A
P1-7
L
Pump Outlet A
System Pump
1.5A
P1-4
L
Pump Outlet C
Auxilliary Pump
1.5A
N
N
DHW
CH
AC to DC
Switch Mode
Power Supply
X6-1
P1-9
P2-1
P1-1
X1-6
X1-7
X2-3
X1-1
Chassis
Ground
X1-2
Ignitor/
Flame Rod
Combustion
Blower
(DC Conn.)
Spark
(DC+)
(Tach.)
(PWM)
(DC-)
HT-1
X3-1
X3-2
X3-3
X3-4
(V2-)
(V2+)
(V1-)
(V1+)
X3-5
X3-6
X3-7
X3-8
+
+
Supply Sensor
Return Sensor
Flue Sensor
DHW Sensor
DHW Flow
X5-1
X5-3
X5-2
X5-4
X5-5
X5-6
X5-7
X5-8
X5-9
X5-10
+
X5-11
X5-12
BCC
X4-4
X4-10
P4-2
P4-1
Model Key
C
P2-3
W
P2-6
R
X6-2
X6-3
Aux T’stat
W
P2-7
R
X6-4
(Recirculation Timer
Or Zone 2 T'stat)
X6-10
+
P2-2
X6-11
X4-1
+
X4-2
X4-5
X4-6
+
Remote Monitoring
Device Power
(optional)
X4-8
RJ11
(MB1)
Controller Front
RJ45
(MB2 & MB3)
RJ45
(MB2 & MB3)
Boiler Control Rear
Limit
String
24VDC
P2-10
X6-6
X6-7
P2-5
X6-8
P2-9
X6-9
P2-8
Outdoor
Sensor
Header Sensor/
Recirculation Sensor
0-10 VDC/
4-20 mA
Boiler Control
S4962VS1014
[System or Zone 1 Pump]
[Recirculation, DHW or Zone 2 Pump]
Boiler Chip Card (BCC)
Model Specific
Protected Parameter Reference
P1
X7
X8-1
X8-2
MB3
Modbus Communication
Boiler to Boiler
MB2
Modbus Communication
Energy Management
System (EMS) Interface
+
+
+
+
+
Figure 20-1: Ladder Diagram