Hitachi RAM-52QH5 Service Manual page 55

MODEL RAM-53QH5
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, 2 and 3 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
Unit 3
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
520
480
Unit 2
0
Hold 500ms
520
480
Unit 3
0
TSKTM1_C and PSTARTC2$ are EEPROM data.
-1 .
1sec.
1sec.
1sec.
100ms
31.25PPS [Outdoor temperature < 40˚C]
Hold
Initialization
finished [Outdoor temperature < 40˚C]
Hold
Initialization
finished
Hold 500ms Hold
-1 during forced cooling, compressor fixed speed control at start is
Forced cooling request
Forced cooling request
Forced cooling request
Outdoor temperature ≥ STARCTP_C
TSKTMI_C1
Outdoor temperature ≤ STARCTP_C
TSKTMI_C2
3000min
< TD control +
PSTARTC2$
< TD control +
PSTARTC2$
[Outdoor temperature < 40˚C]
< TD control +
PSTARTC2$
– 66 –
Lo
-1
N compensation + Diving control >
N compensation + Diving control >
N compensation + Diving control >
Balancing request
Balancing request
Balancing request
30sec.
15sec. +sub
Balancing period 3min.
80sec.