Outline Of Main Controls - Toshiba RAV-SM404SDT-E Service Manual

9-2. Outline of Main Controls

<In case of RAV-SP110 and SP140 models>
1. PMV (Pulse Motor Valve) control
1) PMV is controlled between 30 and 500 pulsed during operation.
2) In cooling operation, PMV is usually controlled with the temperature difference between TS sensor and
TC sensor aiming 1 to 4K as the target value.
3) In heating operation, PMV is usually controlled with the temperature difference between TS sensor and
TE sensor aiming –1 to 4K as the target value.
4) When the cycle excessively heated in both cooling and heating operation, PMV is controlled by TD
sensor. The target value is usually 91°C in cooling operation and 96°C in heating operation.
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 or 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 operation 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.
TD [˚C]
Abnormal stop
111
Frequency normal down
109
Frequency slow down
106
Frequency hold
103
Frequency slow up
(Up to command)
96
As command is
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