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and a demand for heat from the indirect water heater will be
generated when the tank temperature falls below the user set
point by more than the user selectable offset. The demand
will continue until the sensor measures that the indirect water
heater temperature is above the set point.
2. Connect the indirect sensor (7250P-325) to the terminals
marked DHW SENSOR (shown in Figures 22 and 24) in the
electrical junction box.
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 injuries due to scalds.
Caution should be used to ensure neither of these terminals
becomes connected to ground. Failure to do so can result in
property damage, personal injury, or death.
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.
J. Optional 0-10 Volt Building Control Signal
1. A signal from a building
management
system
may be connected to
the boiler to enable
remote control. This
signal should be a 0-10
volt
positive-going
DC signal. When this
input is enabled using
the
installer
menu,
a
building
control
system can be used to
control the set point
temperature
of
the
boiler.
The
control
interprets the 0-10 volt
signal as follows; when
the signal is between 0
and 1.5 volts, the boiler
will be in standby mode,
not firing. When the signal rises above 1.5 volts, the boiler will
ignite. As the signal continues to rise towards its maximum of
10 volts, the boiler will increase in set point temperature. See
Part 10 for details on the setting of function 16.
2. Connect a building management system or other auxiliary
control signal to the terminals marked 16, 0-10 VOLT +
and 17, 0-10 VOLT – in the electrical junction box (shown in
Figure 22). Caution should be used to ensure that the 0-10
VOLT + connection does not become
connected to ground.
3. Move jumper on connection board
(shown in Figure 24) from A to B.
4. See Function 17 this manual to
program the 0-10 volt signal.
NOTE: When a 0-10 volt building
management system is installed, the
return sensor temperature cannot be
monitored through the appliance display.
K. Optional Low Water Cut-Off (LWCO) Kit
If an optional Low Water Cut-Off (LWCO) Kit is used, the LWCO
probe should be mounted into the fitting provided in the outlet
combination fitting.
Follow the complete instructions included in the kit for proper
installation.
L. Wiring of Cascade System Communication Bus
1. A Cascade Bus Termination Plug has been installed on the
customer connection board of this boiler. The purpose of this
plug is to stabilize communication between multiple boilers and
reduce electrical "noise". See Figures 23 and 24 for Cascade Bus
Termination Plug installation detail.
2. Use standard CAT3 or CAT5 computer network patch cables
to connect the communication bus between each of the boilers.
These cables are readily available at any office supply, computer,
electronic, department or discount home supply store in varying
lengths. If you possess the skills you can also construct custom
length cables.
3. It is recommended to use the shortest length cable that will
reach between the boilers and create a neat installation. Do
not run unprotected cables across the floor where they may
become wet or damaged. Avoid running communication cables
parallel and close to or against high voltage (120 volt or greater)
wiring. Westinghouse recommends that the maximum length of
communication bus cables not exceed 200 feet.
4. Route the communication cables through one of the
knockouts in the cabinet.
5. Connect the boilers in a daisy chain configuration as shown
below. It is best to wire the boilers using the shortest wire
runs rather than trying to wire them in the order that they are
addressed. The communication bus jacks on the customer
connection panel are interchangeable so you can use either one
or both in any order to connect the cable.
If you have connected the boilers to each other properly, there
will be no open communication connection ports.
M. Cascade Master Pump and Sensor Wiring
1. Connect the system pump hot wire to the terminal marked 8.
2. Connect the system pump neutral to the 2 terminal and the
pump ground wire to the 3 terminal.
3. Connect a jumper wire from the 120 VOLT terminal to the 9
terminal.
4. Connect the boiler pump to the terminals marked 1 (HOT), 2
(NEUT) and 3 (GND).
5. Connect system pipe sensor to terminals marked 10 and 11.
N. Cascade Follower Pump and Sensor Wiring
1. Connect the boiler pump to the terminals labeled 1 (HOT), 2
(NEUT), and 3 (GND).
2. An alarm bell or light can be connected to the alarm contacts
of the follower boiler. The normally closed alarm contact may be
Figure 23 - Cascade Termination Plug Detail
35
WHL-052 Rev. 4.28.16
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