Specifications

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4) Setting the initial operation pattern
When the compressor is started, the operation starts wish one of the following
operation patterns in accordance with the indoor load.
5) Timing to change operation pattern
Operation pattern is changed by one step at the actuation of the pressure switch
(63L, 63H
3 or 63H4). Once the operation pattern is changed, the same operation
pattern is maintained for 2 minutes.
However, when the frequency which was requested from the indoor side has changed 20 Hz or more, the operation
pattern is changed by one step at the actuation of the pressure swich even if it is within 2 minutes.
6) Changing of operation pattern after a larger change of load
When the indoor load has changed largely like a case when
scales of heating/cooling loads have been inverted, for example,
the operation pattern is changed as follows.
Cooling only
Cooling > Heating
Cooling = Heating
Heating > Cooling
Heating only
Initial operation pattern
A1
A1
B1
C2
D1
Indoor load
Control status
Normal
Temperature control of under dome
Temperature control of discharge pipe
SV1
The solenoid valve (SV1) for compressor cooling is kept OFF at all modes irrespective
of operation/stop of the compressor except ON control.
Note (1) : Open, : Close
/ : Open or close depending on the temperature condition
(8) Solenoid valve for compressor cooling
• Control list
Change from heating large to cooling large
Change from cooling large to heating large
Operation pattern
To A1
To D3
(a) In the case that at least one indoor unit requires the maximum frequency supply during cooling or heating operation for 6
minutes continuously, the compressor operating frequency is increased by 10 Hz. After that, the maximum frequency is
increased by 10 Hz every continuous 6 minutes; however, the upper limit is 30 Hz.
(b) When requirement of the maximum frequency ceases, the control is released.
(c) When the protective function of frequency suppressing is activated during control, the protective motion is performed at
the condition of increased frequency as the base.
(Example: When the current safe is activated at the condition of +20 Hz compensation)
When one of the indoor units is changed over from "Cooling (including automatic), dehumidification and fan mode" to
"Heating (including automatic) mode", or from "Heating mode" to "Cooling, dehumidification and fan mode", the following
control is performed.
(a) During compressor is operating
1) The heating output is kept at the output condition just before cooling/heating change over for 2 minutes and 45 seconds,
after that the heating output of indoor unit where cooling/heating has been changed is changed over.
2) The 4 way valve (20SL, 20SS) is changed over at 2 minutes after the compressor stopped.
Required Hz
from indoor unit
Compressor
operating Hz
50
40
50
40
30
60
Current safe
Current safe released
Indoor unit
requirement
With +20 Hz
compensation
Without +20 Hz
compensation
(9) Compressor operating frequency increase control
(10) Control at heating change over