Toshiba MMU-P0121H Service Manual page 137

3-8-3-3. Outdoor emergency operation in cooling season
(Simple setting method)
<Outline>
When either inverter unit or fixed-speed unit fails during cold season, this function is used to omit various set up
and perform emergency operation quickly.
For cases except those corresponded to cooling operation only, the operation is same as the previously
mentioned "Emergency operation when outdoor unit has failed".
* NOTE 1 : In this setting, heating operation cannot be performed. When receiving a heating command from the
indoor unit, the check code [8C] is displayed and the protective stop status is kept.
(If heating operation is incorrectly performed, the air conditioner is not damaged.)
* NOTE 2 : If a trouble occurred on the interface or electric circuit system, an emergency operation cannot be
performed by this setting. In this case, execute the previously mentioned "Emergency operation
when outdoor unit has failed".
<Work procedure>
(1) First, turn off the power supply of all the outdoor units which are connected to the system.
(2) The following works are performed to the failed outdoor unit. (Even if the failed outdoor unit is the inverter
unit or fixed-speed unit, the following works are common specifications.)
1) Set DIP SW06/Bit 1 and Bit 2 on the interface P.C. board to ON.
2) If refrigerant leakage (Not closed) occurs on even one of PMV A
liquid pipe fully. (Fully close by turning clockwise) (
(3) Turn on power supply of each outdoor unit.
If the fault is a compressor insulation error, etc., disconnect the lead wire of the compressor previously
before work.
(4) Emergency process is complete. The cooling operation then starts by a command from the indoor unit.
3-8-3-4. Automatic backup operation in sensor error of indoor unit
If a sensor used for the indoor unit has failed with a pattern in the following table, the unit starts a backup
operation automatically while displaying the check code. During backup operation, unevenness of capacity
generates because the capacity correction control is not performed.
Accordingly, replace the sensor with error immediately. When a sensor has failed with other pattern than those in
the following table, TC1 + pressure, TC2 + pressure, TC1 + TC2 + TA, etc. for example, the corresponding
indoor unit only stops because there is problem on reliability. (Thermostat OFF)
NOTE :
Never perform backup operation in the outdoor unit during backup operation in the indoor unit because the
compressor may be damaged.
Defective sensor
TC2
Pressure
TC1
TC2 + TA
Pressure + TA
TC1 + TA
Automatic backup operation
Automatic backup operation
TA Automatic backup operation
Automatic backup operation
Automatic backup operation
Automatic backup operation
Automatic backup operation
*
, PMV B close the service valve of the
*
: It is not provided in the cooling only model.)
Measures
3-134
Check code
94
b9
0C
93
94, 0C
b9, 0C
93, 0C