Mitsubishi Electric PURY-P120TJMU-A, Service Handbook, Page: 48 / 411

[
II
Restrictions ]
39 - 39 - HWE0913A GB
(4) Wiring method
1) Indoor/outdoor transmission line
Daisy-chain terminals M1 and M2 of the terminal block
for indoor-outdoor transmission line (TB3) on the outdoor
units (OC and OS) (Note a), of the terminal block for in-
door-outdoor transmission line (TB02) on the main and
sub BC controllers (BC and BS), and of the terminal
block for indoor-outdoor transmission line (TB5) on each
indoor unit (IC). (Non-polarized two-wire)
Œ
Only use shielded cables.
a) The outdoor units in the same refrigerant circuit are auto-
matically designated as OC and OS in the order of ca-
pacity from large to small (if two or more units have the
same capacity, in the order of address from small to
large).
Shielded cable connection
Daisy-chain the ground terminal ( ) on the outdoor units
(OC and OS), the S terminal of the terminal block (TB02)
on the BC and BS, and the S terminal of the terminal
block (TB5) on the indoor unit (IC) with the shield of the
shielded cable.
2) Transmission line for centralized control
Daisy-chain terminals A and B of the system controller,
M1 and M2 terminals of TB7 (terminal block for central-
ized control system connection) on the outdoor units
(OC) in different refrigerant systems, and M1 and M2 ter-
minals of TB7 (terminal block for centralized control sys-
tem connection) on the outdoor units (OC and OS ) in the
same refrigerant circuit. (Note b)
If a power supply unit is not connected to the transmis-
sion line for centralized control, replace the power jump-
er connector on the control board from CN41 to CN40 on
only one of the outdoor units.
When connecting a system controller, set the centralized
control switch (SW2-1) on the control board of all indoor
units to "ON."
b) If TB7's on the outdoor units in the same refrigerant cir-
cuit are not daisy-chained, connect the transmission line
for the central control system to TB7 of the OC. (Note
a).To maintain the central control even during an OC fail-
ure or a power failure, connect TB7 on OC and OS to-
gether. (If there is a problem with the outdoor unit whose
power jumper was moved from CN41 to CN40, central
control is not possible, even if TB7's are daisy-chained.)
Œ
Only use shielded cables.
Shielded cable connection
Daisy-chain the S terminal of the terminal block (TB7) on
the system controller, OC, and OS with the shield of the
shielded cable. Short-circuit the earth terminal (
) and
the S terminal on the terminal block (TB7) on the outdoor
unit whose power jumper connector is mated with CN40.
3) MA remote controller wiring
Same as [5] 1.
When 2 remote controllers are connected to the sys-
tem
Same as [5] 1.
Group operation of indoor units
Same as [5] 1.
4) LOSSNAY connection
Connect terminals M1 and M2 on the terminal block
(TB5) on the indoor unit (IC) to the appropriate terminals
on the terminal block for indoor-outdoor transmission line
(TB5) on LOSSNAY (LC). (Non-polarized two-wire)
Œ
Indoor units must be interlocked with the LOSSNAY unit
using the system controller. (Refer to the operation man-
ual for the system controller for the setting method.) In-
terlock setting from the remote controller is required if the
ON/OFF remote controller alone or the LM adapter alone
is connected.
5) Switch setting
Address setting is required as follows.