Midea MV6-252WV2GN1 Service Manual page 114

Procedure
High pressure sensor connection on main
High pressure sensor has short-circuited
Insufficient refrigerant caused by
refrigerant leakage
The low pressure side is blocked, caused
by crushed or bent pipe, closed EXV or
The evaporator heat exchange is poor
Replace the outdoor main PCB
Notes:
1. High pressure sensor connection is port CN17 on the main PCB (labeled 7 in Figure 5-2.1 in Part 5, 2.1 "Ports").
2. Measure the resistance among the three terminals of the pressure sensor. If the resistance is of the order of mega Ohms or infinite, the pressure sensor has
failed.
3. An insufficiency of refrigerant causes compressor discharge temperature to be higher than normal, discharge and suction pressures to be lower than normal
and compressor current to be lower than normal, and may cause frosting to occur on the suction pipe. These issues disappear once sufficient refrigerant has
been charged into the system. For normal system parameters refer to Table 6-3.4 and 6-3.5 in Part 6, 3.2 "Normal Operating Parameters of Refrigerant
System".
4. A low pressure side blockage causes compressor discharge temperature to be higher than normal, suction pressure to be lower than normal and compressor
current to be lower than normal, and may cause frosting to occur on the suction pipe. For normal system parameters refer to Table 6-3.4 and 6-3.5 in Part 6,
3.2 "Normal Operating Parameters of Refrigerant System".
5. In cooling mode check indoor heat exchangers, fans and air outlets for dirt/blockages. In heating mode check outdoor heat exchangers, fans and air outlets
for dirt/blockages.
H8
PCB is loose 1
No
or failed
2
No
3
No
dirty filter 4
No
5
No
Yes
Ensure the sensor is connected properly
Yes
Replace the sensor
Add refrigerant and inspect system for
Yes
Inspect the system and fix the error. If the
Yes
filter is blocked by ice, the piping should
be cleaned
Yes
Inspect the system and fix the error
V6 VRF 50/60Hz
leaks
113