Hitachi RAM-60QH4 Manuel De Service page 64

FORCED COOLING
• In order to accumulate refrigerant, units operate in cooling cycle.
Execution condition and operation status are shown below.
[Execution condition]
• With neither indoor unit 1 and 2 not operated, when forced cooling switch is turned ON, forced cooling will be performed.
• Always operation status of indoor units are monitored and forced cooling is inhibited when operation of any unit is detected.
[Operation status]
• Outdoor unit fan: Fixed in LO.
• Compressor rotation speed: Fixed in 3000min
• Expansion valve/reversing valve: Set in normal conditions.
[Note]
• During forced cooling, if failure occurs in outdoor unit, thermostat is turned off. However, it is not counted.
• Since rotation speed of compressor is fixed in 3000min
not performed.
• The following shows the operation state of forced cooling.
Power
Service switch
Unit 1
Unit 2
Heating output
Cooling output
Turns on
for Cooling
Outdoor fan
Operation
In-rush Prevention
Power
Approx 100ms
Compressor
rotation speed
520
480
Unit 1
0
Hold 500ms Hold
520
480
Unit 2
0
Hold 500ms
※TSKTM1_C and PSTARTC2$ are EEPROM data.
-1
.
1sec.
1sec.
1sec.
100ms
TSKTM1_C
[Outdoor temperature＜40℃]
•31.25PPS
PSTARTC2$
•Initialization
[Outdoor temperature＜40℃]
finished
PSTARTC2$
Hold
-1
during forced cooling, compressor fixed speed control at start is
Forced cooling request
Forced cooling request
Lo
-1
3000min
<TD control + △N compensation + Diving control>
<TD control + △N compensation + Diving control>
– 76 –
Balancing request
Balancing request
30sec.
15sec.＋sub
Balancing period 3min.
80sec.