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Installation of the M-Net is an essential part of any City Multi installation. The wiring itself is simple but there are a number of
basic rules that must be followed to avoid communication problems within the system.
ALWAYS FOLLOW THE PIPING AND WIRING SCHEMATICS
• There are two separate M-Net control daisy chains in most City Multi installations:
1. The first M-Net starts from TB3 on the first outdoor unit, it is 24-30VDC and daisy chains between outdoor units, branch
controller and indoor units within that system. Star point connections are not acceptable except when wiring in a sub BC
and must have only one star point connection leading to the sub BC (as shown on the piping and wiring schematic).
2. The second M-Net starts from TB7 on the first outdoor unit, it is 22-28VDC and daisy chains from system/central
controllers and all other outdoor units on all systems that are connected to the central controller.
Star point connections
are not acceptable.
• Each M-Net shield must be earthed in
one place only
. Multiple earths can cause the shield to act like an aerial, causing
communication problems.
• M-Net wiring must be kept
separate
from other wiring to avoid induced noise.
M-Net Wiring
RECOMMENDED M-NET WIRING PROCEDURE
Summary of Contents for BDT CITY MULTI
Page 41: ...41 S SERIES OUTDOOR UNIT WIRING INPUTS AND OUTPUTS CITY MULTI ONLY ...
Page 42: ...42 INDOOR UNIT WIRING INPUTS AND OUTPUTS CITY MULTI ONLY INPUTS AND OUTPUTS Continued ...
Page 44: ...44 RECOMMENDED M NET WIRING PROCEDURE CABLE LIMITATIONS AND SYSTEM EXAMPLES ...
Page 47: ...47 ...
Page 48: ...48 BASIC SYSTEM M NET WIRING AND ADDRESSING EXAMPLE M NET ADDRESSING Continued ...
Page 63: ...63 DIP SWITCHES INDOOR UNITS ...
