GREE GMV5E DC INVERTER VRF UNITS SERVICE MANUAL
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Troubleshooting:
2.2.4.20
“b4” Malfunction of liquid temperature sensor of sub-cooler
Error display:
ODU mainboard, IDU wired controller and IDU receive light board will
display
Error judgment condition and method:
Sample the AD value of temperature sensor through temperature sensor detecting circuit and judge
the range of AD value; if the sampled AD value exceeds upper limit and lower limit in 30 seconds
continuously, report the error.
Possible reason
：
■Poor contact between temperature sensor and terminal in mainboard interface
■Temperature sensor is abnormal
■Detecting circuit is abnormal
Troubleshooting:
