Error Code [5402]; Error Code [5403]; Error Code [5701] - Mitsubishi Electric PURY-HP72 Service Handbook

[7-7 Error Code Definitions and Solutions: Codes [5000 - 5999] ]
7-7-21

Error Code [5402]

1. Error code definition
Outside humidity sensor fault
2. Error definition and error detection method
Humidity sensor fault or built-in temperature sensor fault
3. Cause, check method and remedy
1) Check the connector CN22 on the circuit board for proper connection.
2) Check the outside humidity sensor and relay cable for proper connection.
3) Check the output voltage across 2P and 4P of the humidity sensor (CN22).
Conversion of relative humidity to humidity sensor output voltage
20%RH: 1. 2 V or below
40%RH: 1.7V
60%RH: 2.2V
80%RH: 2.7V
Replace the outside humidity sensor if there is a large discrepancy between ambient humidity and the humidity temperature
sensor output voltage.
4) Disconnect the connector CN22 on the circuit board, and check the resistance between 3P and 4P (thermistor resistance of
the built-in temperature sensor)
Conversion of temperature to sensor resistance
0°C: 169kΩ
20°C: 63kΩ
40°C:26kΩ
Replace the outside humidity sensor if there is a large discrepancy between ambient temperature and thermistor resistance.
→ If replacing the sensor does not resolve the problem, resolve the circuit board.
7-7-22

Error Code [5403]

1. Error code definition
Aging degradation of outside humidity sensor
2. Error definition and error detection method
The life of the humidity sensor has expired, and humidity cannot be detected correctly.
3. Cause, check method and remedy
1) Replace the outside humidity sensor.
After replacing the outside humidity sensor, press and hold the maintenance reset switch (SW22) for 5 seconds or longer until
the maintenance reset indication LED2 (green) starts blinking.
→ If replacing the sensor does not resolve the problem, resolve the circuit board.
7-7-23

Error Code [5701]

1. Error code definition
Loose float switch connector
2. Error definition and error detection method
Detection of the disconnected float switch (open-phase condition) during operation
3. Cause, check method and remedy
(1) CN4F disconnection or contact failure
Check for disconnection of the connector (CN4F) on the indoor unit control board.
HWE13080
- 222 -
GB