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Procedure
E3 / E4 / H2 / H3 / Ed / HA / H5 / H9
Temperature sensor connection on
hydronic box main PCB is loose
Temperature sensor has short‐circuited
Replace hydronic box main PCB
Notes:
1.
Backup electric heater water outlet temperature sensor,
exchanger refrigerant outlet (gas pipe) temperature sensor, water side heat exchanger water inlet temperature sensor and water side heat exchanger
water outlet temperature sensor connections are port CN6 on the hydronic box main PCB (labeled 11 in Figure 4‐2.1 in Part4, 2.2 "Main PCB for Hydronic
System").
Domestic hot water tank temperature sensor connection is port CN13 on the hydronic box main PCB (labeled 12 in Figure 4‐2.1 in Part4, 2.2
"Main PCB for Hydronic System"). Circuit 2 water outlet temperature sensor connection is port CN15 on the hydronic box main PCB (labeled 13 in Figure
4‐2.1 in Part4, 2.2 "Main PCB for Hydronic System"). Room temperature sensor connection is port CN16 on the hydronic box main PCB (labeled 14 in Figure
4‐2.1 in Part4, 2.2 "Main PCB for Hydronic System").
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 Table 4‐5.1 or 4‐5.3 in Part 4, 5.1 "Temperature Sensor Resistance Characteristics".
201909 47
No
2
or failed
No
water side heat exchanger refrigerant inlet (liquid pipe) temperature sensor, water side heat
Midea CAC Confidential
Yes
Ensure the sensor is connected properly
Yes
Replace the sensor
M‐Thermal Split
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