Hitachi FSXN Series Service Manual page 83

4 Electrical wiring
Connect the communication cable on the corresponding units to the same refrigerant cycle. (Where the refrigerant pipe of
the indoor unit is connected to the outdoor unit, connect the communication cable to the same indoor unit).
N O T E
Connecting the refrigerant pipe and the communication cable to units in different refrigerant cycles may lead to
operating problems.
Use shielded twisted pair cable or shielded pair cable. Do not use cable with three or more conductors.
Use the same type of cables for the H-LINK system of units in each refrigerant cycle.
Ensure a minimum distance of 50 mm between the power cables and the communication cables and 1500 mm between
these and the power cables of other electrical devices. Where this is not possible, install power cables in a metal duct
separate from the others.
Connect the communication cables to TB2 terminals 1 and 2 on outdoor unit A (main unit):
• Between the outdoor unit and the indoor unit.
• Between the outdoor unit and the CH unit.
• Between the outdoor unit and the indoor unit on other refrigerant cycles.
C A U T I O N
Do not connect power cables to communication terminals (TB2). This could damage the circuit board.
For heat recovery systems, connect the communication cable on the indoor unit (used exclusively for refrigeration) to TB2
terminals 1 and 2 on the CH unit.
Connect the earth wire for the outdoor units, the indoor units and the CH units. Earthing connections below a resistance of
100 Ω (max.) must be made by qualified personnel.
N O T E
1 Set the DSW switches on the main and secondary units for the combination of (20-54) HP outdoor units.
2 An alarm is triggered if the communication cables between the outdoor units are connected to terminals 1 and
2 for H-LINK II.
3 Where an alarm is indicated on the display of the main outdoor unit, follow the instructions given to make the
necessary checks.
4 Make the function settings from the main outdoor unit.
5 Maximum number of refrigeration groups with one remote control: 64.
Maximum number of indoor units connected: 160.
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SMGB0065 rev. 1 - 12/2010