System Control; Outline Of System Control - Daikin FTX25JVEA9 Service Manual

Si18-201
3.

System control

3.1

Outline of System Control

Power supply ON
Compressor / OFF
Unit stop (standby control)
· Warming-up function
· Cooling electrical switch box
Compressor / ON
Has
the previous
standby operation
completed?
Operation start
· Initial frequency (differ from cooling and heating)
· Decision of initial motorized valve opening.
(differ from cooling and heating)
Feedback control
Cooling SC control (Decision for EVL open/close)
EVL: Close
(Independent VRV control)
BP unit
SH control
Target discharge pipe temp. control
EVG
Target discharge pipe temp. control
<Excess refrigerant processing>:
Subcooling control in cooling
· Refrigerant is stored in the piping
before EV of BP unit.
Cooling capacity control
System protection control
· Gas shortage control
· Wet protection control
· Peak cut / Freeze protection control
Main Functions
ON command
NO
Start-up standby operation
YES
Cooling
EVL: Open
(Super-multi control)
BP unit
Gas pipe isothermal control
Target discharge pipe temp. control
EVG
—
· Discharge pipe temp. control
· Differential pressure securing fin control
· Year-round cooling
Heating
BP unit capacity control (Decision for EVG open/close)
(1 or 2 step control)
EVG: Close EVG: Open
(Super-multi control) (Independent VRV control)
BP unit BP unit
SC control SC control
Target discharge pipe temp. control
EVG
Reverse target discharge pipe control
EVG
—
EVL
Target discharge pipe control
EVL
—
<Excess refrigerant treatment>:
Reverse target discharge pipe temp. control in heating
· Firstly refrigerant is stored inside the piping
in the no-operation room unit.
· When overflow command is generated,
refrigerant is stored in the receiver.
Heating capacity control

System control

3-minutes standby
· Equalizing control
· Fan OFF delay
OFF command
(Before equalizing)
· Standby operation
ON
OFF
command
command
NO
YES
ON ?
Command
Completed
Defrost control
Heating
· Oil return control
YES
OFF control
Is
heating oil
return control
required?
Cooling
· Oil return control
ON control
· Input current control
· Compressor protection control
· High pressure control
NO
(M1003)
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