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NOTE: When a 0-10 volt building management system is installed, the return sensor temperature cannot be monitored through the
boiler display.
NOTE: Ensure that the polarity of the connections from the external modulating boiler controller to the boiler is correct. Reversed
polarity could lead to erratic and/or no response from the boiler controller.
K. OPTIONAL UL353 LOW WATER CUT-OFF INTERFACE KIT
If an optional UL 353 Low Water Cut-Off (LWCO) Interface Kit is used, the control box of the kit should be mounted to the left side of
the boiler cabinet near the low water cut-off probe, which is located on the outlet nipple of the boiler.
Follow the complete instructions included in the kit for proper installation.
NOTE: The control system senses system water temperatures entering and exiting the heat exchanger to provide protection against
low water conditions. Where local codes or jurisdictions do not accept a pressure device for low water protection, the jurisdictions may
accept these control functions as a means of providing low water protection.
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 Figure 31 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
Figure 30 – LP-387-W
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.
WHL-016 REV. 12.18.14
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