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• The compressor ON/OFF and operational frequency are controlled according to the discharge temperature.
(1) Compressor ON/OFF
The compressor turns OFF when the discharge temperature thermistor rises above 120°C. The compressor turns ON
when the discharge temperature thermistor falls below 80°C.
(2) Compressor operational frequency
When the estimated discharge temperature is high than 120°C, the compressor operational frequency will decrease by
8 Hz from the current operational frequency. When the estimated discharge temperature is over 115°C to 120°C inclu-
sive, the compressor operational frequency will decrease by 4 Hz from the current operational frequency.
When the estimated discharge temperature is over 107°C to 115°C inclusive, the compressor operational frequency will
be fixed to the current operational frequency.
<Conditions to active refrigerant recovery>
The system activates refrigerant recovery when it satisfies all the following conditions :
• One or more indoor unit are standstill during heating operation. (It does not include the "Thermostat OFF" starts.)
• The discharge temperature rises to 107°C or above.
• Sixty minutes or more have passed since the operation start-up or the last refrigerant recovery.
<Control details>
• The LEV opening is controlled at 80 pulse for the non-operating indoor unit(s).
<Conditions to discontinue refrigerant recovery>
The system discontinues refrigerant recovery when it satisfies either of the following conditions. Then the LEV opening
is controlled to 59(MXZ-32RV) / 49(MXZ-18RV) pulse.
• Sixty seconds have passed since the start-up of refrigerant recovery.
• The discharge temperature falls to 90
;
(MXZ-32RV) / 100
;
(MXZ-18RV) or below.
Relation between major sensors and actuators.
Discharge tempera-
ture thermistor
Purpose
Protection
Defrosting
Control
Control
Control
Protection
Protection
Protection
Control
Compressor
LEV
Outdoor
fan motor
Reversing
valve
2-way valve
(MXZ-32RV)
Sensor
Defrost thermistor
Suction temperature
thermistor
Fin temperature
thermistor
Capacity code
Low pressure switch
(MXZ-32RV)
Evaporation tempe-
rature thermistor
Gas pipe tempera-
ture thermistor
High pressure
switch
Actuator
11-10.9.Discharge temperature protection
11-10.10.Refrigerant recovery in heating
11-10.11.Sensors and actuators
