Communication Malfunction; Overcurrent Protection; Compressor High-Pressure Protection; Compressor Overload Protection - Gree GWHD14NK3BO Service Manual

Function and Control

2.4 Communication malfunction

Detection of the quantity of installed indoor units:
After 3min of energizing, if the outdoor unit does not receive the communication data of certain indoor unit, the outdoor unit will
judge that indoor unit is not installed and will treat it as it is not installed. If the outdoor unit receives the communication data of
that indoor unit later, the outdoor unit will treat that unit as it is installed.

2.5 Overcurrent Protection

a. Overcurrent protection of complete unit; b. phase wire current protection; c. compressor phase current protection

2.6 Compressor high-pressure protection

2.6.1 When the high-pressure switch is detected cut off for 3s continuously, the compressor will enter high-pressure protection
as it stops when reaching set temperature. Meanwhile, the outdoor unit will send the signal of "high-pressure protection" to the
indoor units;
2.6.2 After the appearance of high-pressure protection, when the high-pressure switch is detected closed for 6s continuously,
the compressor can resume running only after cutting off the power and then putting through the power.

2.7 Compressor overload protection

If the compressor overload switch is detected having movement, the indoor unit will display the corresponding malfunction as it
stops when the indoor temperature reaching set temperature. When the compressor stops for more than 3min and the
compressor overload switch is reset, the unit will resume operation status automatically. If the protection appears for more than
6 times (if the running time of the compressor is longer than 30min, the protection times record will be cleared), the unit can not
resume operation status automatically, but can resume running only after cutting off the power and then putting through the
power.
2.8 Compressor Phase-lacking Protection
When the compressor starts, if one of the three phases is detected open, the compressor will enter phase-lacking protection.
The malfunction will be cleared after 1min, the unit will restart and then detect if there is still has phase-lacking protection. If the
phase-lacking protection is detected for 6 times continuously, the compressor will not restart but can resume running only after
cutting off the power and then putting through the power. If the running time of the compressor is longer than 7min, the
protection times record will be cleared.

2.9 IPM Protection

2.9.1 When the IMP module protection is detected, the unit will stop as the indoor temperature reaching set temperature, PFC is
closed, display IMP protection malfunction. After the compressor stops for 3min, the unit will resume operation status
automatically; if the IMP protection is detected for more than 6 times continuously (If the running time of the compressor is
longer than 7min, the protection times record will be cleared), the system will stop and send the signal of module protection to
indoor unit. The unit can not resume operation status automatically, but can resume running only after cutting off the power and
then putting through the power.
2.9.2 IMP module overheating protection
2.9.2.1 When T 85 , prohibit to raise frequency;
IMP
2.9.2.2 When T ≥ 90 , the operation frequency of compressor lows down by 15% every 90s according to the present
IMP
capacity requirement of the complete unit. It will keep 90s after lowing down the frequency. After lowing down the frequency, if
T ≥ 90 , the unit will circulate the above movement until reaching the minimum frequency; if 85 T 90 , the unit will
IMP IMP
run at this frequency; when T ≤ 85 , the unit will run at the frequency according to the capacity requirement;
IMP
2.9.2.3 When T ≥ 95 , the compressor stops. After the compressor stops for 3min, if T 85 , the compressor and the
IMP IMP
outdoor fan will resume operation.
22