Low Pressure Protection Control; Discharge Pipe Protection Control - Daikin VRV EMERION RXYQ-AATJA Service Manual

SiUS342303E
6.2

Low Pressure Protection Control

This low pressure protection control is used to protect compressors against the transient decrease
of low pressure.
Cooling
Because of common low pressure, the following control is performed in the system.
Heating
The following control is performed in the system.
6.3

Discharge Pipe Protection Control

This discharge pipe protection control is used to protect the compressor internal temperature
against an error or transient increase of discharge pipe temperature.
HTdi: Value of compressor discharge pipe temperature (Tdi) compensated with outdoor air
temperature
Ti: Compressor body temperature
A: Maximum of HTdi and Ti
The following control is performed for each compressor of single unit as well as multi units.
Part 4 Functions and Control
Normal control
Pe < 0.25 MPa
(36.3 psi)
Reduce compressor capacity step
Pe < 0.07 MPa
(10.2 psi)
Low pressure standby
Normal control
Pe < 0.05 MPa
(7.3 psi)
Reduce compressor capacity step
Pe < 0.02 MPa
(2.9 psi)
Low pressure standby
Normal control
A > 108°C
(226°F)
Reduce compressor capacity step
HTdi > 135°C
Discharge pipe temperature standby
Pe > 0.39 MPa
(56.6 psi)
Pe > 0.1 MPa
(14.5 psi)
A < 95°C
(203°F)
(275°F)
Protection Control
Pe: Low pressure sensor detection
value for master unit.
When occurring 3 times within 60
minutes, the error code E4 is output.
When occurring 3 times within 60
minutes, the error code E4 is output.
When occurring 3 times within 100
minutes, the error code F3 is output.
(Sub code - 01, 02, 03)
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