Troubleshooting Chart; What To Be Prechecked First - Toshiba RAS-07EKH Service Manual

Troubleshooting Procedures:
• Following details of "What to be prechecked first", make sure of the basic items.
• When there is no trouble corresponding to above, check in detail the faulty parts following "How to judge
faulty parts by symptoms" later.

9-1. What to be Prechecked First

9-1-1. Power Supply Voltage
The line voltage must be AC 220/230/240V. If the line
voltage is not within this range, this air conditioner
may not work normally.
9-1-2. Incorrect Cable Connection between
Indoor and Outdoor Units.
The indoor unit is connected to the outdoor unit with 5
cables. Make certain that the indoor and outdoor units
have been connected properly, with terminals assigned
the same numbers wired to each other. If the connec-
tors are not connected as specified, the outdoor unit
will not operate normally. It should be noted that if
terminals 1 and 3 or terminals 1 and 4 are connected
together by mistake, some copper foil patterns on the
control section PC board may be broken.
• Misleading but good operations
Operation of air-conditioner
When the POWER plug socket of the indoor unit is
inserted, the OPERATION lamp on the setting indication
part flashes.
Fan speed remains unchanged in teh dry mode.
Room temperature is in the range under which the
compressor is turned off, but the compressor will not stop.
The compressor will not switch on or off even when the
thermo control is operated in the dry operation.
The PRE.-DEF. lamp comes on when the heating
operation is started.
The outdoor fan stops once in a while during the heating
operation.

9. TROUBLESHOOTING CHART

Table 9-1
– 32 –
9-1-3. Misleading but Good Operations
(Program Controlled Operation)
The microcomputer performs the operations listed in
Table 9-1 to control the air conditioner. If a claim is
made on the operation, check whether it corresponds
to the contents in the Table 9-1. If it does, it is an
indispensable operation for the control and mainte-
nance of the air-conditioner: it is not a failure of the
unit.
Description
The OPERATION lamp flashes, indicating that power is
turned on. If this happens, press the START/STOP
button once to cause the lamp to stop flashing. A power
outage also causes the lamp to flash.
Fan speed is fixed at Low in the dry mode.
The compressor will not stop while the compressor on-
hold timer (two-minute timer) is actuated.
In the dry mode, the compressor goes on and off at
regular intervals, independent of the Thermo control.
The PRE.-DEF. lamp comes on during defrost operation
and when the indoor heat exchanger temperature is low
when the heating operation is started. At this time, the
indoor fan is stopped to prevent cold air from drifting into
the room.
• Whent eh indoor heat exchanger temperature is high,
the outdoor fan may be stopped by teh high-temprature
limit control operation.
• When the compressor current is large, the outdoor fan
may be stopped by teh current control operation.