Toshiba RAS-18YKH-E Service Manual page 15

7-6. High-Temperature Limit Control
(Heating Operation)
The microprocessor detects the indoor heat ex-
changer temperature so as to prevent exceeding the
condensate pressure.
Control is performed as shown in Fig. 7-6-1.
Heat exchanger
temperature
(˚C)
60
*
1
54
52
*
1 ····· Only outdoor fan is turned off.
Fig. 7-6-1
7-7. Low-Temperature Limit Control
(Cooling Operation)
The microprocessor detects the indoor heat ex-
changer temperature so as to prevent freezing up
the indoor heat exchanger.
Control is performed as shown in Fig. 7-7-1.
Heat exchanger
temperature
(˚C)
12
2
Fig. 7-7-1
Compressor,
Outdoor fan
OFF
ON
Compressor
Outdoor fan
ON
Less than 2˚C continues
for 6 minutes
OFF
– 15 –
7-8. Cool Airflow Prevention Control
(Heating Operation)
(1) During the heating operation, the indoor fan
speed is controlled automatically in accordance
with the indoor heat exchanger temperature to
prevent blowing the cool air.
Control is performed as shown in Fig. 7-8-1.
Heat exchanger
temperature
(˚C)
30
26
20
16
Fig. 7-8-1
(2) As soon as the defrost operation starts, the
indoor fan stops.
7-9. Defrost Operation
During heat operation, if the temperature (Evaporat-
ing temperature) detected by the outdoor heat
exchange sensor (TE :Defrost) lowers by the set
degree less than the temperature detected at start
time, the operation enters the defrost operation. In
this time, the 4-way valve relay and the outdoor fan
are turned off. The indoor fan is turned off by the
cool air blow-out preventing control of the indoor
microcomputer at the indoor side, and "PRE.-DEF."
on the remote control goes on.
The defrost operation is automatically reset to the
normal operation when the temperature detected by
the above-mentioned TE sensor rises up to the set
value, or when Max. 12 minutes of the operation
time has passed.
Indoor fan speed
According to the
set position
L (Low)
OFF