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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 26). 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 26) from A to B.
4. See Part 9, Section D, Function 17 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 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.
L. WIRING OF CASCADE SYSTEM COMMUNICATION BUS
1. 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.
2. 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. HTP
recommends that the maximum length of communication bus cables not exceed 200 feet.
3. Route the communication cables through one of the knockouts in the cabinet.
4. 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, two of the boilers will have one open
connection port on them.
Summary of Contents for EL-110
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Page 61: ...61 Figure 29 ...
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Page 89: ...89 Figure 35 LP 293 A NOTE Parts listed on the following page ...
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Page 96: ...96 MAINTENANCE NOTES ...