Header Outdoor Unit Backup Operation Setting; Unit) - Toshiba MMY-MUP0721FT6P-UL Service Manual

9-3-2. Header outdoor unit backup operation setting (failure of header outdoor unit)
<Work procedure>
(1) Turn off the power supply to all the units connected to the system at the source.
[Setup of failed header outdoor unit]
(2) Fully close the service valves of the HP/LP gas pipe and the LP gas pipe of the failed outdoor.
(3) Leave the service valve of the liquid pipe fully open (to prevent refrigerant stagnation in the failed).
(4) <In case of failure in compressor, electrical part, P.C. board>
From this point on, keep the power supply to the failed unit off.
<In case of failure in refrigerating circuit or related part (pressure sensor, temperature sensor, refrigerating
cycle part, or fan system part)>
Disconnect the line for outdoor-outdoor communication [Uc (U5/U6)] and cover the U5 and U6 line with
insulating tape separately. (Do not cover the line by mixing the U5 and U6 line altogether).
Setup of failed outdoor
Leave the service valve of the liquid pipe open.
(If there is leakage from outdoor PMV,
fully close the service valve.
[Selection of new header unit]
(5) Select a new header unit from the follower units on the basis of the following criteria:
• If only one follower unit is connected, select it as the header unit.
• If two follower units are connected, select the follower unit that is nearest to the failed header unit.
[Setup of new header unit]
(6) Set SW101 and SW102 on the interface P.C. board same as the setting of failed header unit (refrigerant line
address setting).
(7) Turn on Bit3 of SW103 on the interface P.C. board. (Setting to prevent connected indoor unit capacity over
failure. (E16))
(3)
In case of failure in refrigerating circuit
or related part, disconnect the line for
outdoor-outdoor communication [Uc
(U5/U6)] and cover the U5 and U6 line
with insulating tape separately.
( Do not cover the line by mixing the
U5 and U6 line altogether.)
(2)
Fully close the service valves of the
HP/LP gas pipe and the LP gas pipe.
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(4)