Daikin VRV S RXQ4/5ARV1 - Page 70

Control for 4/5/10/12 HP Outdoor Unit SiAF332111E
64 Part 4 Functions and Control
1.4.2 Low Pressure Protection Control
This low pressure protection control is used to protect compressors against transient decreases
in low pressure.
Cooling operation
1.4.3 Discharge Pipe Protection Control
This discharge pipe protection control is used to protect the compressor from high internal
temperature during abnormality or transient increase of discharge pipe temperature.
Pe < 0.25 MPa
36 Hz Unload
Pe > 0.39 MPa
Pe
< 0.07 MPa
Low pressure not limited
Pe: Low pressure sensor detection value
Pe < 0.15 MPa Pe > 0.30 MPa
Hot gas bypass valve: OFF
Hot gas bypass valve: ON
When occurring 3 times within 30 minutes,
the error code E4
is output.
Low pressure
standby
Low pressure
limited
• HTdi > 115˚C
• Tp > 135˚C
OR
36 Hz Unload
• HTdi > 115˚C
• Tp > 135˚C
OR
• HTdi > 135˚C
• HTdi > 120˚C for 10 minutes or more.
OR
• HTdi < 110˚C
• Tp < 125˚C
&
After 30 seconds
After 20 seconds
• HTdi > 130˚C
• HTdi > 120˚C
OR
• HTdi < 100˚C
• Tp < 110˚C
&
Discharge pipe
temperature standby
Discharge pipe protection
control not limited
Compressor upper limit
frequency: 1-step down from
current compressor frequency
In discharge pipe
temperature protection
control
When occurring 3 times within 100 minutes,
the error code F3 is output.
Compressor upper limit frequency: 1-step
up from current compressor frequency
Tp: Value of compressor port temperature
calculated by Tc, Te, and suction
superheating degree.
HTdi: Value of compressor discharge pipe
temperature (Tdi) compensated with
outdoor air temperature
for 90 seconds
or more.