Daikin RXYQ72 Serivce Manual page 58

SiUS39-601
3.6.2 Stopping Operation of Slave Units During Master Unit is in Operation
with Multi-Outdoor-Unit System
In cooling operation: The system operates in Mode A or Mode B listed in the table below.
Actuator
Compressor
Outdoor unit fan
Four way valve
Main motorized valve (EV1)
Subcooling motorized valve (EV2)
Hot gas bypass valve (SVP)
Oil equalization valve (SVO)
Receiver gas discharging valve
(SVG)
Non-operating unit liquid pipe stop
valve (SVSL)
Mode transition conditions
Ending conditions
In heating operation: The system operates in Mode A or Mode B listed in the table below.
Actuator
Compressor
Outdoor unit fan
Four way valve
Main motorized valve (EV1)
Subcooling motorized valve (EV2)
Hot gas bypass valve (SVP)
Oil equalization valve (SVO)
Receiver gas discharging valve
(SVG)
Non-operating unit liquid pipe stop
valve (SVSL)
Mode transition conditions
Ending conditions
∗ Mode A or B operation

Mode A : Operating unit collects refrigerant.


Mode B : Stopping unit storage refrigerant.
The changeover operation for mode A and B is performed for the reason that the required refrigerant amount varies
depending on the indoor unit operation capacity.
Function
Mode-A operation
OFF
STEP4
OFF
150 pls to 300 pls
0 pls
ON
OFF
OFF
OFF
To Mode B when Tc-Tl >0.27×(Tc - Ta) +6
Slave units are required to operate.
Mode-A operation
OFF
STEP2
ON
0 pls
0 pls
OFF
OFF
OFF
OFF
To Mode B when Tc-mean temperature of
indoor unit liquid pipes>10°C
Slave units are required to operate.
Operating Stopping
unit unit
Mode-B operation
OFF
OFF
Holds
0 pls
0 pls
ON
OFF
OFF
ON
To Mode A when gas shortage signal
is sent from indoor unit
Mode-B operation
OFF
STEP2
ON
0 pls
0 pls
OFF
OFF
OFF
ON
To Mode A when motorized valve of
operating outdoor unit fully opens.
Special Control
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