Midea MC-SU30-RN1L Service Manual

Aqua Tempo Super II
201709 81
Part
4 - Diagnosis and Troubleshooting
4.15 Pb Troubleshooting
Digital display output 4.15.1
Description 4.15.2
 Water side heat exchanger anti-freeze protection.
 All units stop running.
 Error code is displayed on main PCB and ANTI.FREEZE icon is displayed on user interface.
Possible causes 4.15.3
 Normal system protection.
 Temperature sensor not connected properly or has malfunctioned.
 Main PCB damaged.
Procedure 4.15.4
Pb
Min(Tw/Two/Twi/Taf) ≤ 4°C in normal
cooling mode or min(Tw/Two/Twi/Taf) ≤
0°C in low water outlet mode
1
Yes
Normal system protection. The system
will resume automatically
2
No
Tw/Two/Twi/Taf temperature sensor
loose
Yes
Ensure the temperature sensor is
connected properly
No
Tw/Two/Twi/Taf temperature sensor has
short-circuited or failed
3
Yes
Replace the temperature sensor
No
Replace outdoor main PCB
Notes:
1. Combined water outlet temperature sensor (Tw), Water side heat exchanger water outlet temperature sensor(Two), water side heat exchanger water inlet
temperature sensor (Twi) and water side heat exchanger anti-freezing temperature sensor(Taf, include Taf1 and Taf2) connections are ports CN69 and
CN31 on the main PCB (labeled 23 and 24 in Figure 4-2.1 in Part 4, 2.2 “Outdoor unit main PCB”).
2. Refer to Part 3, 6.7 “Water Side Heat Exchanger Anti-freeze Protection Control”.
3. 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 Table 4-5.1 in Part 5, 5.1 “Temperature Sensor Resistance Characteristics”.

Midea MC-SU30-RN1L Specifications

General

Brand	Midea
Model	MC-SU30-RN1L
Category	Chiller
Language	English