Outdoor Unit Backup Operation Setting; Follower Outdoor Unit Backup Operation Setting; Unit) - Toshiba MMY-MUP0961HT6P-UL Service Manual

9-3. Outdoor Unit Backup Operation Setting

<Outline>
This product allows outdoor unit backup operation setting to be performed either at the header unit or a
follower unit. If any of the failure modes specified below occurs to one of the outdoor units in a multi-outdoor
unit system, proceed with outdoor unit backup operation.
• A compressor failure (e.g. a layer short-circuit or a compressor failure in which no compressor is available to
back up the failured compressor)
• A failure of a pressure sensor (Pd or Ps) or a temperature sensor (TD1, TD2, TS1, TS3, TE1, TE2, TE3, TG1,
TG2, TG3, TK1, TK2, TL1, TL2 or TL3)
Note: Keep the number of backed-up outdoor units to one in the system (single refrigerant line).
9-3-1. Follower outdoor unit backup operation setting (failure of follower outdoor unit)
<Work procedure>
(1) Turn off the power supply to all the indoor and outdoor units connected to the system.
[Setup of failed follower outdoor unit]
(2) Fully close the gas pipe service valve of the failed outdoor unit.
(3) Leave the service valve of the liquid pipe fully open (to prevent refrigerant stagnation in the unit).
However, if there is a leakage from an outdoor PMV (unable to close), fully close the liquid pipe service
valve.
(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.
<Case of refrigerating cycle parts failing (pressure sensor, temperature sensor, refrigerating cycle parts, fan
system part)>
• In a case where the outdoor unit that is a terminal connection fails, disconnect the communication line to
the outdoor unit from terminal [Uc(U5/U6)], and cover each of the lines U5 and U6 with insulating tape.
Header unit
Uv Uc
U1 U2 U5 U6
To indoors
• In a case where an intermediate-connection outdoor unit fails, disconnect the communication line between
both adjacent outdoor units from terminal [Uc(U5/U6)], and connect the communication lines.
Header unit
Uv Uc
U1 U2 U5 U6
To indoors
(Reference) Normal wiring
Header unit
Uv Uc
U1 U2 U5 U6
To indoors
Follower unit 1 Follower unit 2
Uc
Failure
U5 U6
Follower unit 1 Follower unit 2
Uc
Failure
U5 U6
Follower unit 1 Follower unit 2
Uc
U5 U6
Uc
U5 U6
Uc
U5 U6
Uc
U5 U6
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