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Label all wires prior to disconnecting them when servicing the
boiler. Wiring errors can cause improper and dangerous operation.
Failure to follow these instructions may result in property damage
or personal injury.
Wiring must be NEC Class 1. If original wiring supplied with the
boiler must be replaced, use only TEW 105
Boiler must be electrically grounded as required by the National
Electrical Code, ANSI/NFPA 70 - Latest Edition.
A. Installation Must Comply With
1. National Electrical Code and any other national, state, provincial,
or local codes or regulations.
2. In Canada, CSA C22.1, Canadian Electrical Code Part 1, and any
local codes.
B. Field Wiring
Terminations
All
connections
made
to
the
boiler in the field
are done inside
the
electrical
junction
box
located on the
left side of the
unit.
Multiple
k n o c k o u t
locations
are
available to route
Figure 21 - Knockout Locations
field wires into and out of the electrical junction box.
C. Field Wiring
The control used in the boiler is capable of directly controlling
2 pumps in standard mode and 3 pumps when configured as a
cascade master boiler. As a standard unit, each pump can provide a
maximum of 2 amps at 120 volts. If a pump requires more than this
amount of power, an external contactor or motor starter is needed.
The electrical junction box has separate, clearly marked terminal
strips for line voltage and low voltage wiring. Special jacks are
provided for trouble-free cascade system wiring using standard
CAT3 or CAT5 patch cables.
D. Line Voltage Wiring for Standard Boiler
NOTE: A termination plug is included in the CAT 3 / CAT 5 Bus
Connection Point, labeled J3 in Figure 22. DO NOT REMOVE THIS
PLUG! Doing so will affect boiler operation and void warranty.
1. Connect 120V / 60Hz / 15 AMP incoming power wiring to the
line voltage terminal strip in the electrical junction box at terminals
120V, Neutral, Ground (shown in Figure 22).
2. A line voltage fused disconnect switch may be required, externally
mounted and connected according to local codes that may apply.
3. Connect the boiler pump as shown in Figure 22 to the terminals
marked 1 – (HOT), 2 – (NEUT), and 3 – (GND). The connections shown
are suitable for a maximum continuous pump draw of 2 amps at
120 volts. If the pump requires more current or voltage than the
120 volts supplied, an external motor starter or contactor will be
required.
E. Alarm Connections
The control includes a dry contact alarm output. This is an SPDT
circuit, rated at 5 amps at 120 volts. This contact can be used to
activate an alarm light or bell or notify a building management
system if the boiler goes into a lockout condition. The circuit
between the ALARM COM and NC terminals is closed during normal
operation and the circuit between ALARM COM and NO is open during
normal operation. The connections depicted in Figure 22 show two
120 volt lights connected to the alarm terminals. One light will be on
when the boiler is in normal mode and the other light will be on when
the boiler is in lockout mode.
F. Low Voltage Connections for Standard Boiler
1. All low voltage cables should enter the electrical junction box
through the provided knock out holes as shown in Figure 21.
2. Connect all low voltage field devices to the low voltage terminal
o
C wire or equivalent.
strip located in the electrical junction box.
G. Tank Sensor or Mechanical Control
Connect the tank sensor or mechanical controls to the TANK SENSOR
terminals (10, 11) of the low voltage terminal strip as shown in Figure
22. The control will automatically determine which type of sensor is
connected and operate accordingly.
Failure to use the correct sensor may result in tank temperature
being either above or below set point, and could result in decreased
performance, substantial property damage, or heightened risk of
injury or death due to scalds.
Caution should be used to ensure neither of these terminals becomes
connected to ground.
NOTE: If sensor wires are located in an area with sources of potential
electromagnetic interference (EMI), the sensor wires should be
shielded, or the wires routed in a grounded metal conduit. If using
shielded cable, the shielding should be connected to the common
ground of the boiler.
H. System / Pipe Sensor
The
can be used to control the
temperature of the storage
tank when a tank sensor or
mechanical control cannot
be mounted. The system/
pipe sensor would be wired
into the terminals of the
low voltage terminal strip
as shown on Figure 22. It
is important to note that
when a system/pipe sensor
is used, the circulating pump
must be wired to operate
continuously; otherwise the
boiler will short cycle.
The system/pipe sensor can
also be used in a cascade
system when the sensor is
placed on the supply line
of multiple boilers that feed the storage tank. This will control the
temperature and modulate the firing rate of the connected boilers.
The system/pipe sensor would then be wired into the master boiler
terminals on the low voltage strip as shown on Figure 24.
NOTE: If sensor wires are located in an area with sources of potential
electromagnetic interference (EMI), the sensor wires should be
shielded, or the wires routed in a grounded metal conduit. If using
shielded cable, the shielding should be connected to the common
ground of the boiler.
system/pipe
sensor
WHL-053 Rev. 00 Rel. 003 Date 7.21.17
33
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