Toshiba MMY-MAP0804FT7(Z), Service Manual, Page: 120 / 333

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7-2. Check Items before Test Operation (before poweringon)
Prior to the test operation, check the following items to verify there are no problems with the installation work.
Main check items for electric wiring
The communication system differs from that of R22 or R407 refrigerant “Modular Multi system” air conditioners.
Check wiring points again carefully.
(1) In the case that a central control system is not connected:
U1 U2
U1 U2 U1 U2 U1 U2 U1 U2
U5 U6
U3 U4
U1 U2 U5 U6
U3 U4
U1 U2 U5 U6
U3 U4
A B A B A B A B
(1) (2) (4) (3)
(5)
(6)
Outdoor unit
Indoor unit
Remote
controller Remote
controller Remote
controller
Header unit (A) Follower unit (B) Follower unit (C)
Main check items Check
(1) Are the indoor and outdoor communication lines of the header unit connected to the U1/U2 terminals?
(2) Is the relay connector between the U1/U2 terminal and the U3/U4 terminal removed? (Set up at
shipment from the factory)
(3) Is the communication line between outdoor units connected to the U5/U6 terminal?
(4) Is the terminal resistance (SW30-bit 2) on the interface PC board of the header unit turned on? (Set
up at shipment from the factory)
(5) Is the end terminal of the shield wire open?
(6) Is the end terminal of the shield wire earthed at the header unit side?
NOTE
The figure above does not show all the electric wires.
For details, refer to the installation manuals for the outdoor unit, indoor unit, remote controller, or optional
devices.
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