Midea MDV-V80W/DN1

MCAC-VTSM-2013-12 R410a Full DC Inverter Mini VRF
Troubleshooting 105
7.3 E4: Pipe temperature T3& ambient temperature T4 sensor malfunction (for all models)
Case: There is no display on PCB of one system, and the problem still exists after replacing PCB. Voltage
values on measuring plate (such as 220V, 5V, 12V, etc.) are normal; after measuring resistance value of
sensor, find that T4 thermo-bulb is earth-continuity, and further discover that the thermal cable of T4
sensor is punched by bolt, as follows:
LED displays E4
Whether the wire body is broken.
PCB is disabled.
Pipe temperature T3& ambient temperature T4 sensor
malfunction
Connect the wire again.
YES
NO
Judge whether temperature sensor pin connects
properly.
YES
Connect again.
NO
NO
Replace PCB.
T4 sensor is worn out and
connected with sheet metal
After being reconnected, the
system becomes normal