Outdoor Control Circuit; Outline Of Main Controls; Pulse Modulating Valve (Pmv) Control; Discharge Temperature Release Control - Toshiba RAV-GM301ATP-E Service Manual

7-1. Outline of Main Controls

1. Pulse Modulating Valve (PMV) control

1) For PMV 50 to 500 pulses during operation.
2) In cooling operation, PMV is controlled with the temperature difference between TS sensor and TC
sensor.
3) In heating operation, PMV is controlled with the temperature difference between TS sensor and TE
sensor.
4) For the temperature difference in items 2) and 3), -1 to 5K is aimed as the target in both cooling and
heating operations.
REQUIREMENT
A sensor trouble may cause a liquid back-flow or abnormal overheat resulting in excessive shortening of the
compressor life. In a case of trouble on the compressor, be sure to check there is no error in the resistance
value an the refrigerating cycle of each sensor after repair and then start the operation.

2. Discharge temperature release control

1) When the discharge temperature did not fall or the discharge temperature rapidly went up by PMV
control, this control lowers the compressor frequency. It subdivides the frequency control up to 0.6Hz
to stabilize the cycle.
2) When the discharge temperature detected an abnormal stop zone, the compressor stops and then
restarts after 2 minutes 30 seconds.
The error counting is cleared when the operation continued for 10 minutes. If the error is detected by
4 times without clearing, the error is determined and restarting is not performed.
∗ The cause is considered as excessively little amount of refrigerant, PMV error or clogging of the cycle.
3) For displayed contents of error, confirm on the check code list.

7. OUTDOOR CONTROL CIRCUIT

TD [˚C]
Abnormal stop
117
Frequency normal down
112
Frequency slow down
108
Frequency hold
105
Frequency slow up
(Up to command)
98
As command is
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FILE NO. SVM-18042-1