Wellea Monobloc
19
P
art
3
- Con
tr
ol
4.7
Spray liquid cooling control
When the discharge temperature of compressor exceeds 105
℃
, the solenoid valve opens and the frequency of
compressor drops in order to reduce the discharge temperature. When the discharge temperature is below 90
℃
, the
solenoid valve closes.
If the discharge temperature exceeds 108
℃
while the spray liquid cooling control is in progress, which is judged every 20s,
the frequency of compressor drops 4Hz until the minimum frequency which differs from every model. When the discharge
temperature is below 95
℃
, the compressor runs at the current frequency.
5
Protection Control
5.1
High Pressure Protection Control
This control protects the refrigerant system from abnormally high pressure and protects the compressor from transient
spikes in pressure.
Figure 3-6.1: High pressure protection control
Notes:
1.
P
c
: Discharge pressure
When the discharge pressure rises above 4.2MPa the system displays P1 protection and the unit stops running. When the
discharge pressure drops below 3.2MPa, the compressor enters re-start control.
5.2
Low Pressure Protection Control
This control protects the refrigerant system from abnormally low pressure and protects the compressor from transient
drops in pressure.
Figure 3-6.2: Low pressure protection control
Notes:
1.
P
e
: Suction pressure
When the suction pressure drops below 0.14MPa the system displays P0 protection and the unit stops running. When the
suction pressure rises above 0.3MPa, the compressor enters re-start control.
When P0 protection occurs 3 times
in 60 minutes, the HP error is
displayed. When an HP error occurs,
a manual system restart is required
before the system can resume
operation.
P
e
< 0.14MPa
P
e
> 0.30MPa
Normal operation
Low pressure protection, error code P0 is displayed
