GREE U-Match 5 SERIES UNIT SERVICE MANUAL
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3.4.17 ―H3‖ Compressor Overload Protection
Error display: ODU mainboard, IDU wired control and IDU receiver light board will display H3
Error judgment condition and method:
When the mainboard‘s interface ovc-comp is broken off for 3s, error H3 will be reported.
Possible reason:
■The interface ovc-comp is not short-circuited.
■ODU mainboard is damaged.
Troubleshooting:
H3 compressor overload
protection compressor overload
protection
Check if the over comp. interface on the
mainboard is connection
Replace the
mainboard
Connection the over
comp. interface
YES
NO
3.4.18 ―H4‖ Overload
Error display: ODU mainboard, IDU wired control and IDU receiver light board will display H4
Error judgment condition and method:
When tube temperature is higher than the protection value, system will report overload protection.
Possible reason:
■Cooling ODU heat exchanger is blocked or heat exchange is bad.
■Heating IDU heat exchanger is blocked or heat exchange is bad.
■Operating temperature is too high.
■System charging quantity is too much.