Midea V4+R Series - 4.18.4 Procedure; 4.19

V4+R VRF 50/60Hz
84 201608
Midea V4+R Series Service Manual
Procedure 4.18.4
P5
ODU stop valves are closed
Yes
Open the stop valves
No
Outdoor heat exchanger temperature
sensor connection on main PCB is loose
1
Yes
Ensure the sensor is connected properly
No
Outdoor heat exchanger temperature
sensor has short-circuited or failed
2
Yes
Replace the sensor
No
The indoor load is too large
3
Yes
Make sure the combination ratio is less
than 130%
No
System contains air or nitrogen
4
Yes
Flush all refrigerant then vacuum the
system and recharge the refrigerant. Add
oil to the system if it leaks
No
The condenser heat exchange is poor
5
Yes
Inspect the system and fix the error
No
The high pressure side is blocked, caused
by crushed or bent pipe or blocked EXV
6
Yes
Inspect the system and fix the error
No
Replace outdoor main PCB
Notes:
1. Outdoor heat exchanger temperature sensor connection is port CN1 on the main PCB (labeled 32 in Figure 5-2.1 in Part 5, 2.1 “Ports”).
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance
characteristics table, the sensor has failed. Refer to Part 2, 1 “Layout of Functional Components” and to Table 5-5.1 in Part 5, 5.1 “Temperature Sensor
Resistance Characteristics”.
3. An indoor load that is too large causes suction and discharge temperatures to be higher than normal. For normal system parameters refer to Tables 5-5.4
and 5-5.5 in Part 5, 5.2 “5.2 Normal Operating Parameters of Refrigerant System”.
4. Air or nitrogen in the system causes discharge temperature to be higher than normal, discharge pressure to be higher than normal, compressor current to
be higher than normal, abnormal compressor noise and an unsteady pressure meter reading. For normal system parameters refer to Tables 5-5.4 and 5-5.5
in Part 5, 5.2 “5.2 Normal Operating Parameters of Refrigerant System”.
5. In cooling mode check outdoor heat exchangers, fans and air outlets for dirt/blockages. In heating mode check indoor heat exchangers, fans and air outlets
for dirt/blockages.
6. High pressure side blockage causes discharge temperature to be higher than normal, discharge pressure to be higher than normal and suction pressure to
be lower than normal. For normal system parameters refer to Tables 5-5.4 and 5-5.5 in Part 5, 5.2 “5.2 Normal Operating Parameters of Refrigerant
System”.