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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 unit 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 3900min
-1
.
[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 3900min
-1
during forced cooling, compressor fixed speed
control at start is not performed.
The following shows the operation state of forced cooling.
Power
Power
In-rush Prevention
Approx 100ms
31.25PPS
Hold 500ms
Hold 500ms
Initialization finished
TSKTM1
3900rpm
Balancing period 3min.
15sec. + sub
80sec.
100ms
Service switch
Heating output
Cooling output
Outdoor fan
Turns on
for Heating
Operation
Unit 1
Unit 2
Unit 1
Compressor
rotation speed
Main microcomputer
Electric expansion valve
Power relay
Compressor
Reversing
valve
Unit 2
1sec
1sec
1sec
Lo
Forced cooling request Balancing request
Forced cooling request Balancing request
520
480
0
520
480
0
[Outdoor temperature<40°C]
[Outdoor temperature<40°C]
PSTART
PSTART
<TD control + 3N compensation + Diving control>
<TD control + 3N compensation + Diving control>
❈ ● TSKTM1 and PSTART are EEPROM data.
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