Toshiba RAV-SM2804AT8-E, RAV-SM2804AT8Z-E Outline of Main Controls, PMV Pulse Motor Valve control

7-2. Outline of Main Controls

1.PMV (Pulse Motor Valve) control

1)The aperture of the PMV (1, 2) is controlled between 88 (44 + 44) to 1000 (500 + 500) pulses during operation.

2)During cooling and heating operations, the PMV aperture is controlled by the temperature difference between a detected temperature from a TS sensor and a saturation temperature equivalent value (TU temperature) from a Ps sensor. (SH control).

3)The temperature difference in 2) in both cooling and heating operations is usually controlled using a 5K target value.

(However control may be performed within a range of 1 – 15K depending on operating conditions).

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 96°C for cooling operations and 102°C for heating operations.

CAUTION

Sensor malfunction may cause liquid back-flow or error overheating 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 errors 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 an error zone, compressor operation is stopped and then restarted after 2 minutes 30 seconds.

An error count is added on each occasion the error zone is detected and when the error is detected 4 times, a “P03” error is performed.

When normal operation continues for a period of 10 minutes, the error count is cleared.

TD (˚C)

Abnormal stop

([P03] is displayed with count 4 of errors)

115

Frequency normal down

113

Frequency slow down

105

Frequency hold

102

Frequency slow up (Until command)

95

According to command

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