44
Installation & Operation Manual
5
Electrical connections
Line voltage connections
1. Connect 120 VAC power wiring to the line voltage
terminal strip in the junction box, as shown in FIG. 5-1.
2. Provide and install a fused disconnect or service switch
(15 AMP recommended) as required by the code (see
FIG. 5-1).
3. To activate a system pump, wire as shown in FIG. 5-1. If
the motor is larger than 1 HP, you must install a contactor.
4. When connecting power to units which are to be
cascaded, each unit must be connected to the same ground
connection.
D
I
S
C
O
N
N
E
C
T
L
N
SYSTEM
PUMP
RELAY COIL
R
120V
SUPPLY
DHW
PUMP
RELAY COIL
UNIT
PUMP
1 HP MAX
R
LB
L2017
5 RE
V
A
D
I
S
C
O
N
N
E
C
T
D
I
S
C
O
N
N
E
C
T
D
I
S
C
O
N
N
E
C
T
L
N G
L
N G
L
N G
L
N G
UNIT
SUPPLY
UNIT PUMP
SUPPLY
SYSTEM
PUMP SUPPLY
DHW PUMP
SUPPLY
BOILER ONLY
BOILER
PUMP
SYSTEM
PUMP
DHW
PUMP
CHASSIS
GROUND
GROUND
SPLICE
120V
RELAY
120V
RELAY
Figure 5-1_Line Voltage Field Wiring Connections
Low voltage connections
1. Route all low voltage wires through the knockouts on the left
side of the heater, as shown in FIG. 5-2.
2. Connect low voltage wiring to the low voltage connection board
as shown in FIG. 5-4 on page 46 of this manual and the heater
wiring diagram.
LOW
VOLTAGE
KNOCKOUTS
LINE
VOLTAGE
KNOCKOUTS
Figure 5-2_Routing Field Wiring
EMS or remote thermostat connection
An EMS, remote thermostat or other remote temperature
control may be connected to the boiler (see FIG. 5-3).
Follow the manufacturer’s instructions supplied with
the remote temperature control for proper installation
and adjustment. Connection of a set of dry switching
contacts or a remote on/off thermostat to the low voltage
connection board will allow the unit to be switched
on and off by making or breaking a 24 VAC control
circuit. Remove the factory jumper between the Staging
S1 terminals on the low voltage connection board and
connect the remote temperature control in its place, see
FIG. 5-4 on page 46.
REMOTE
ON/OFF
CONNECTION
Figure 5-3_Remote ON/OFF Wire Connection
Ensure that all wiring used to connect the switching
contacts of the remote temperature controller to the
connection board are a minimum of 18 gauge and have
a maximum installed length of 300 feet (91.4m). Set
the SMART SYSTEM control to a set point temperature
slightly higher than the setting of the remote temperature
control. This will ensure that the remote temperature
controller functions as the operating control for the
heater.
DHW (Domestic Hot Water) thermostat
Connect the DHW tank thermostat (FIG. 5-4) to the tank
thermostat terminals on the connection board.
DHW tank sensor
If a tank sensor is used, it must be connected to the tank
sensor terminals on the low voltage connection board. The
correct Lochinvar sensor (TST20015) MUST BE USED.