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COMMUNICATION (RS 485) WIRING
System Control
Boiler Monitor
• Use Belden #9842 Cable Or Equivalent (See Note). Polarity must be observed. Make
use of wire color coding to ensure proper polarity.
• The shielding foil wrapper - bare wire (drain) - MUST be grounded.
Grounding is done at the System Control Module only. DO NOT ground at Boiler
Monitor.
•
Note: Equivalent shielded cable must be suitable for RS 485 communication
applications; must have 100-140 ohm impedance; and less than 30 picofarad per foot
capacitance.
• Install in conduit with no other wiring.
RS 485 Communications Cable Schematic
Page 13
NOTE: Tighten terminal strip
clamping screws 20 lbs - In
(2.26N.m) Breakage from over
torquing is not covered under
warranty.
Use copper conductors only.
For supply connections use
wires sized on the basis of 60°C
Ampacity and rated Min. 90°C
(194°F).
BELDEN #9842
BOILER MONITOR SYSTEM CONTROL
TERMINAL TB 3 TERMINAL TB2