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Toshiba
8-4.
Outdoor unit
control
1)PMV (Pulse motor valve) control
Valve opening is controlled using the expansion valve with a pulse motor according to a heat pump operation status.
• PMV is controlled between 30 and 500 pulses during an operation.
• At the time of a cooling operation, PMV is controlled with the usual target value of 1 to 4 K temperature difference
between TS sensor and TC sensor.
• At the time of a hot water supply or heating operation, PMV is controlled with the usual target value of 2 to 4 K (for
802H-E) or -1 to 4 K (for 1102, 1402H-E) temperature difference between TS sensor and TE sensor.
• For both cooling and heating, if the cycle is overheated, PMV is controlled using the TD sensor.The usual target value
is 91°C for a cooling operation, and 96°C for a heating operation.
* A defective sensor may cause liquid back flow or abnormal overheat of the compressor, significantly shortening the
compressor life. If the compressor or other equipment is repaired, first check that the resistance of each sensor or
the refrigerant cycle has no problem, then start the operation.
2)Discharge temperature release control
This control detects an abnormality of the refrigerant cycle or compressor to perform failure prevention.
• This control reduces operation frequency if the PMV control does not lower the outlet temperature or if the outlet
temperature rapidly rises. The frequency control is broken down to the unit of 0.6 Hz to stabilize the cycle.
• If the discharge temperature detects the abnormal stop zone, the compressor stops and then restarts after 150
seconds. The abnormality detection counter is cleared when the operation continues for 10 minutes. If detected 4
times, the error code is displayed and the compressor does not restart.
* An abnormality could occur due to too less refrigerant, PMV defective, or cycle stuck.
• For details about an error displayed, see the check code list.
Item Operation flow and applicable data, etc.
TD [
°C
]
111
109
106
103
96
Abnormal stop
Frequency normal down
Frequency slow down
Frequency hold
Frequency slow up
(up to the point instructed)
As instructed
+00A09-002_01EN_SVM_ALL_Air_to_Water.book Page 57 Monday, October 5, 2009 2:09 PM