Protection Control - Midea V8 Series Service Manual

V8/V8i PRO VRF 50Hz

6 Protection Control

6.1 High Pressure Protection Control
This control protects the system from abnormally high pressure and protects the compressors from transient spikes in
pressure.
6.2 Low Pressure Protection Control
This control protects the system from abnormally low pressure and protects the compressors from transient drops in
pressure.
Figure 3-6.3: Low pressure protection control in cooling operation
P < 0.07MPa
e
Low pressure protection, error code P22 is displayed
Notes:
P : Suction pressure
1.
e
6.3 Discharge Temperature Protection Control
This control protects the compressors from abnormally high temperatures and transient spikes in temperature. It is
performed for each compressor.
When the Max temperature of compressor discharge temperature rises above 115°C the system displays F72 protection and
all units stop running. When F72 protection occurs 3 times in 100 minutes, the F7A error is displayed. When an F7A error
occurs, a manual system restart is required before the system can resume operation.
50
Figure 3-6.1: High pressure protection control
Normal operation
P 4.15MPa
≥
c
High pressure protection, error code P12 is displayed
Notes:
1. P : Discharge pressure
c
Normal operation
P 0.15MPa
≥
e
Figure 3-6.5: Discharge temperature protection control
Normal operation
T7C_max 115°C
≥
Discharge temperature protection, error code F72 is displayed
Notes:
1. T7C_max: Max temperature of compressor discharge temperatures
P < 3.5MPa
c
When P22 protection occurs 3 times
in 60 minutes, the P25 error is
displayed. When an P25 error occurs,
a manual system restart is required
before the system can resume
operation.
T7C_max < 90°C