Midea M-Thermal Series Service Manual page 68

Procedure
Discharge pipe temperature sensor
connection on outdoor unit main PCB is
Backup electric heater water outlet
temperature sensor connection,
domestic hot water tank temperature
sensor connection or water side heat
exchanger water outlet temperature
sensor connection on hydronic box main
Temperature sensor has short‐circuited
High pressure switch connection or
pressure sensor connection on outdoor
unit main PCB is loose
Pressure sensor has short‐circuited or
The high pressure side is blocked, caused
by crushed or bent pipe or blocked EXV
The condenser heat exchange is poor in
The water flow rate is not sufficient in
Replace outdoor main PCB
Notes:
1. Discharge pipe temperature sensor connection is port CN8 on the outdoor unit main PCBs (labeled 11 in Figure 4‐2.2 in Part4, 2.3 "Main PCBs for
201909 67
P4
1
loose
No
2
PCB is loose
No
3
or failed
No
4
No
5
failed
No
No
5
heating mode
No
6
cooling mode
No
Midea CAC Confidential
Ensure the temperature sensor is
Yes
Ensure the temperature sensor is
Yes
Yes
Ensure the pressure switch is connected
Yes
Yes
Replace the pressure sensor
Yes
Inspect the system and fix the error
4
Yes
Inspect the system and fix the error
Inspect the water system and fix the
Yes
M‐Thermal Split
connected properly
connected properly
Replace the sensor
properly
error