Backup Operation; Emergency Operation - Toshiba MM-A0280HT Service Manual

When One Compressor has Failed (Backup Setup of Compressor)
Outline
When one of two compressors installed in the outdoor unit fails, take the following action if
emergency operation by another normal compressor is possible.
* NOTE 1: In the case of single compressor installed unit (6HP), backup operation by one
compressor is unavailable. In this instance refer to the "Emergency Operation when
an outdoor unit has failed" section.
* NOTE 2: For the emergency operation when the failed compressor is an inverter, the
capacity control is performed by ON/OFF control of fixed-speed compressor.
* NOTE 3: When motor winding of the compressor fails (Short, etc.), do not set backup of the
compressor because deterioration of oil will occur.
(Another error in the outdoor unit may be caused.)
Work procedure
(1) First, turn off the source power of all the outdoor units which are connected to the
system.
(2) The following works are performed to the outdoor unit of which the compressor failed.
According to the following table, set DIP switch (SW06) on the interface P .C. board.
Table Switch setup in compressor backup
Initial setup at shipment from factory
No.1 compressor (INV) (Front left compressor) has failed
No.2 compressor (FIX) (Front right compressor) has failed
(3) Backup setup is now complete. Turn on the source power of all the outdoor units.
When an Outdoor Unit has Failed
In this air conditioner, backup operation is permissible to both an inverter unit and a
fixed-speed unit when an outdoor unit has failed.
In a system in which two or more outdoor units are connected, perform the emergency
operation for failure of outdoor unit when alarm mode, such as one of the following cases,
occurs.
(1) Fault of compressor (Short or when one compressor is not operating)
(2) Fault of pressure sensor (Pd, Ps)/fault of temp. sensor (TD1, TD2, TS, TE, TK1, TK2, TK3)
(3) Fault of refrigerating cycle parts, fan system parts, interface P .C. board, inverter P .C. board,
electric part system, etc.
CAUTION: Emergency operation should only be completed on 1 outdoor unit per
system.

Backup Operation

Emergency Operation

101
SW06
Bit 1 Bit 2 Bit 3 Bit 4
OFF OFF OFF OFF
ON OFF OFF OFF
OFF ON OFF OFF
15