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32
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 23). Caution should be used to ensure that the 0-10
VOLT + connection does not become connected to ground.
K. Optional High Gas Pressure Switch
1. If an optional high gas pressure switch is used, it should be
installed on the outlet side of the gas valve. This is normally closed
and will open if the pressure goes above 1.5" w.c. on the outlet side.
2. Locate the two pigtails hanging from the electrical box inside of
the boiler cabinet. Remove and discard the jumper plug from one of
the unused pigtails.
3. Connect the high gas pressure switch to the pigtail that you
removed the jumper plug from.
L. Optional Low Gas Pressure Switch
1. If an optional low gas pressure switch is used, it should be installed
on the inlet side of the gas valve. This is normally closed and will
open if the pressure goes below 1" w.c. on the inlet side.
2. Locate the two pigtails hanging from the electrical box inside of
the boiler cabinet. Remove and discard the jumper plug from one of
the unused pigtails.
3. Connect the low gas pressure switch to the pigtail that you
removed the jumper plug from.
M. Optional Flow Switch
NOTE: Follow the more detailed instructions included with the flow
switch kit for proper installation steps.
1. Attach the correct flow paddle to the flow switch.
2. Thread brass tee onto outlet nipple using pipe dope. Make
certain the branch points up on horizontal runs.
3. Thread flow switch into tee using pipe dope. Make certain the
FLOW arrow points in the correct direction.
4. Disconnect red wire on the low water cut off probe and connect it
to the red wire from the wire harness (included in kit).
5. Feed green ground wire into boiler through the wire access.
6. From the front of the boiler, feed the ground wire up into the
control box.
7. Once into the control box, attach the green ground to the ground
bus connection.
8. Connect red wire from flow switch to boiler wire harness.
9. When installation is complete, power up the boiler and use the
control to access installer parameter #20 and change the default
value to 2 (see Part 11 in this manual). When done, create a demand
and observe boiler function to verify the installation is working
whl-445 Rev. 000 Rel. 014 Date 7.21.20
properly.
NOTE: Installing the optional flow switch will disable the built-in low
water cutoff. If a flow switch and a low water cutoff are necessary
for the installation, purchase and install the optional UL353 LWCO
(available from Westinghouse, Part # 7350P-601). In this installation, it
is recommended to install the flow switch kit first.
N. Optional UL353 Low Water Cut-Off Interface Kit
1. If an optional UL353 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.
2. If the optional flow switch is present on the boiler, then the orange
wire from the LWCO control box is left unconnected. If the optional
flow switch is not installed on or connected to the boiler, remove
the wire connected to the low water cut-off probe on the boiler and
connect it to the orange wire from the newly mounted LWCO control
box.
3. Connect the single red wire from the control box to the low water
cut-off probe on the boiler.
4. Route the rest of the wires through the hole provided in the cabinet
and down by the main electrical enclosure.
5. Locate the two pigtails hanging from the main electrical enclosure.
Select the pigtail which has a white, red, and brown wire in it. If the
pigtail is connected to a gas pressure switch, skip to step 7. If this
pigtail is not connected to a gas pressure switch, remove the jumper
plug from the end of the pigtail and place the jumper plug into the
mating connector coming from the LWCO control box.
6. Connect the pigtail to the remaining plug coming from the LWCO
control box. Installation is complete.
7. If the pigtail located in step 5 is connected to a gas pressure switch,
disconnect it from the gas pressure switch and connect the pigtail to
the mating connector coming from the LWCO control box. Connect
the gas pressure switch to the remaining connector from the LWCO
control box.
O. 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 25 and 26 for Cascade Bus Termination Plug installation
detail.
NOTE: It is important that the termination plug in multiple boilers
(cascaded units) be installed as depicted in Figure 25. Leave the plug
installed in the J3 port on the Master boiler. Remove the plug on
intermediate Follower boilers. Move the plug to the J4 port on the final
Follower boiler.
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.
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