Protection Control
SiUS281117
Function and Control
45
4.2
Low Pressure Protection Control
Pe: Low pressure sensor detection value
This low pressure protection control is used to protect compressors against the transient
decrease of low pressure.
[Cooling]
[Heating]
Pe
<
36 psi
57Hz
Pe
>
57 psi
Pe
<
10 psi
Low pressure not limited
When occurring 3 times within 60 min.,
the error code
"
E4
" is output.
Low pressure
standby
Low pressure
limited
Pe
< 10 psi
145.5Hz
Upper limit:
&
&
SVP = OFF
SVP = ON
• Pe > 36 psi
• Inverter upper limit
frequency
More than 145.5Hz
Pe < 23 psi
Upper limit:
57Hz
Upper limit: 1-step up from
current compressor frequency
Low pressure not limited
Low pressure limited
Pe > 28 psi (every 20 sec.)
Pe > 25 psi
Pe < 19 psi
Pe < 19 psi
Pe < 23 psi
Pe < 15 psi
Pe > 28 psi
Low pressure
standby
When occurring 3 times within 60 min.,
the error code "
E4
" is output.
SVP: Solenoid valve (Hot gas)
