Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

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[2-2 Types and Maximum Allowable Length of Cables ]
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2-2 Types and Maximum Allowable Length of Cables
1. Wiring work
(1) Notes
1) Have all electrical work performed by an authorized electrician according to the local regulations and instructions in this man-
ual.
2) Install external transmission cables at least 5cm [1-31/32"] away from the power supply cable to avoid noise interference.
(Do not put the control cable and power supply cable in the same conduit tube.)
3) Provide grounding for the outdoor unit as required.
4) Run the cable from the electric box of the indoor or outdoor unit in such way that the box is accessible for servicing.
5) Do not connect power supply wiring to the terminal block for transmission cable. Doing so will damage the electronic compo-
nents on the terminal block.
6) Use 2-core shielded cables as transmission cables.
Do not use a single multiple-core cable to connect indoor units that belong to different refrigerant systems. Doing so may result
in signal transmission errors and malfunctions..
7) When extending the transmission cable, be sure to extend the shield wire.
(2) Control wiring
Different types of control wiring are used for different systems. Before performing wiring work, refer to the following page(s).
[2-7 Example System with an MA Remote Controller]
[2-8 Example System with an ME Remote Controller]
[2-9 Example System with an MA and an ME Remote Controller]
Types and maximum allowable length of cables
Control lines are categorized into 2 types: transmission line and remote controller line.
Use the appropriate type of cables and observe the maximum allowable length specified for a given system. If a given system
has a long transmission line or if a noise source is located near the unit, place the unit away from the noise source to reduce
noise interference.
1) M-NET transmission line
Cable type
Facility
type
All facility types
Type Shielded cable CVVS, CPEVS, MVVS
Number of
cores
2-core cable
Cable size Larger than 1.25mm
2
[AWG16]
Maximum transmission
line distance between the
outdoor unit and the far-
thest indoor unit
200 m [656ft] max.
Maximum transmission
line distance for central-
ized control and Indoor/
outdoor transmission line
(Maximum line distance
via outdoor unit)
1000 m [3280ft] (500 m [1640ft]) max.
*1
*The maximum overall line length from the power supply unit on the transmission lines for
centralized control to each outdoor unit or to the system controller is 200m [656ft] max.
*1 If a given system includes one or more unit or remote controller that does not support
the maximum allowable cable distance of 1,000 m [3280 ft], the maximum allowable ca-
ble distance in the system will be 500 m [1640 ft]. Refer to the latest catalog for informa-
tion on which units and remote controllers support the maximum allowable cable
distance of 1,000 m [3280 ft].
TB
3
TB
7
TB
3
TB
7
TB
3
TB
7
TB
3
TB
7
multiple-core cable
Hydro unit Indoor unit
Remote Controller
Remote Controller
2-core shielded cable
2-core shielded cable
Outdoor unit
Hydro unit Indoor unit
Outdoor unit
TB3: Terminal block for indoor-outdoor transmission line TB7: Terminal block for centralized control
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