31
Part 3 - Con
trol
6 Protection Control
6.1 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 for 30kW and 60kW units
Normal operation
P
c
> 4.2MPa
P
c
< 3.2MPa
Low pressure protection, error code P0 is displayed
When P0 protection occurs 3 times
in 60 minutes, a manual system
restart is required before the system
can resume operation.
Notes:
1. P
c
: Discharge pressure
When the discharge pressure rises above 4.2MPa the system displays P0 protection and all units stop running. When the
discharge pressure drops below 3.2MPa, the compressor enters re-start control.
6.2 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 for 30kW and 60kW units
Normal operation
P
e
< 0.14MPa
P
e
> 0.3MPa
Low pressure protection, error code P1 is displayed
When P1 protection occurs 3 times
in 60 minutes, manual system restart
is required before the system can
resume operation.
Notes:
1. P
e
: Suction pressure
When the suction pressure drops below 0.14MPa the system displays P1 protection and all the units stop running. When
the suction pressure rises above 0.3MPa, the compressor enters re-start control.
6.3 Discharge Temperature Protection Control
This control protects the compressor from abnormally high temperatures and transient spikes in temperature.
Figure 3-6.3: High discharge temperature protection control for 30kW and 60kW units
Normal operation
Discharge temperature > 115°C
Discharge temperature < 90°C
High discharge temperature protection, error code P0 is
When P0 protection occurs 3 times
in 60 minutes, ta manual system
restart is required before the system
can resume operation.
When the discharge temperature rises above 115°C the system displays P0 protection and all the units stop running. When
the discharge temperature drops below 90°C, the compressor enters re-start control.