Outline Of Main Controls - Toshiba RAV-GM 801UT-E Service Manual

7-2. Outline of Main Controls

1. PMV (Pulse Motor Valve) control
1) The aperture of the PMV is controlled between 30 to 500 pulses during operation.
2) During cooling operations, the PMV aperture is controlled by the temperature difference between TS
sensor and TC sensor, the temperature difference in cooling operations is usually controlled using a 1 to
4K target value.
3) During heating operations, the PMV aperture is controlled by the temperature difference between TS
sensor and TE sensor, the temperature difference in heating operations is usually controlled using a -1 to
4K target value.
4) When the cycle overheats during both cooling and heating operations, the PMV aperture is controlled
using a detection value from a TD sensor.
The normal target value is 91°C for cooling operations and 96°C for heating operations.
Sensor malfunction may cause liquid back-flow or overheating trouble in the compressor resulting in dramatic
reduction in the durable life of the compressor.
In the event of malfunction and repair of the compressor, restart operation after checking that there are no
trouble in the resistance values or the refrigerating cycle of each sensor.
2. Discharge temperature release control
1) This control lowers the revolution number of the
compressor in the event that the discharge
temperature is not reduced or in the event the
discharge temperature increases rapidly during
PMV control.
The cycle is stabilized by dividing compressor
revolution number control into units up to 0.6
rps.
2) When the detected discharge temperature is in
a trouble zone, compressor operation is stopped
and then restarted after 2 minutes 30 seconds.
A trouble count is added on each occasion the
trouble zone is detected and when the trouble is
detected 4 times, a "P03" trouble is performed.
When normal operation continues for a period of
10 minutes, the trouble count is cleared.
When normal operation continues for a period of
10 minutes, the trouble count is cleared. When
the trouble is detected 4 times without the
trouble count being cleared, the trouble is
recognized so that the operation does not
restart.
∗ An extremely less refrigerant, PMV failure and
a cycle clogging etc may cause the
malfunction of the operation.
3) For the indicated contents of trouble, confirm
using the check code lists.
CAUTION
<GP80>
TD (˚C)
([P03] is displayed with count 4 of trouble)
111
109
103
100
Frequency slow up (Until command)
93
<GP110, 140>
TD (˚C)
([P03] is displayed with count 4 of trouble)
111
109
106
103
Frequency slow up (Until command)
96
– 51 –
Abnormal stop
Frequency normal down
Frequency slow down
Frequency hold
According to command
Abnormal stop
Frequency normal down
Frequency slow down
Frequency hold
According to command