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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. 5-2.
2. Provide and install a fused disconnect or service switch
(15 AMP recommended) as required by the code (see
FIG. 5-2).
3. To activate a system pump, wire as shown in FIG. 5-2. If
the motor is larger than 1 HP, you must install a contactor.
UNIT
SUPPLY
L
N
D
I
S
C
O
N
N
E
C
T
L
N
120V
SUPPLY
1 HP MAX
Figure 5-2_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. 5-3.
2. Connect low voltage wiring to the low voltage connection
board, reference the connection diagram on pages 66 and
67 of this manual.
LOW VOLTAGE
KNOCKOUTS
LINE VOLTAGE
KNOCKOUTS
Figure 5-3_Routing Field Wiring
UNIT PUMP
SUPPLY
G
L
N
G
D
I
S
C
O
N
N
E
C
T
UNIT
PUMP
GROUND
SPLICE
CHASSIS
GROUND
UNIT
PUMP
IMG00594
IMG00595
Installation & Operation Manual
External EMS connection to terminal
strip for stage firing control of burners
This unit is equipped with a factory installed terminal strip
for connection of an energy management system (EMS) to the
burner stages. The EMS terminal strip is located in the unit's
control panel. Ensure that all wiring used for connection to
this terminal strip is properly sized per the recommendations
in TABLE 5A. When connecting an EMS to this terminal
strip to sequence on each stage of burner operation, the unit's
electronic control should be set to Sequencer Mode 3 to act as
an additional high limit control. This will prevent problems
between the setpoints of the EMS and the water heater's
internal controller.
Terminal strip connection options
on page 40)
Figure 5-4 shows the position of jumpers as shipped from the
factory for stand-alone operation of water heaters.
Figure 5-5 shows connections to the terminal strip for Remote
ON/OFF control of the water heater. The 1C-1NO jumper
must be removed when making these wiring connections. This
remote ON/OFF control will provide an Enable/Disable signal
to the unit and allow the unit to operate based on the stage
setpoints, until the remote ON/OFF signal is cancelled.
Figure 5-6 shows the connections necessary to operate the unit
as a two-stage (High/Low Fire) water heater from an Energy
Management System (EMS). For use with EMS, the controller
should be set to Mode 3 and the Boil Max adjusted to the
desired seeting to allow the controller to act as an upper limit
while the EMS controls the actual setpoint temperature.
Figure 5-7 shows the Continuous and Intermittent terminals.
External safety devices connected to these terminals will function
to protect the unit. Devices connected to the Intermittent
terminals (B1 and B2) are monitored only when there is an
active Call for Heat. Devices connected to the Continuous
terminals (A1 and A2) are monitored continuously and will
activate an alarm (if the unit is equipped with the alarm option)
anytime the safety device senses an abnormal condition.
Figure 5-8 shows the wiring of a tank sensor. A tank sensor
must be wired to the low voltage terminal strip in order for the
pump delay to function properly.
(reference figures
39
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