21
Technical Information
Service Manual
②
Protection
a. In cooling operation, protection is the same as that under the cooling mode;
b. In heating operation, protection is the same as that under the heating mode;
c. When ambient temperature changes, operation mode will be converted preferentially. Once started, the compressor will
remain unchanged for at least 6 minutes.
(6) Common Protection Functions and Fault Display under COOL, HEAT, DRY and AUTO Modes
①
Overload protection
T tube: measured temperature of outdoor heat exchanger under cooling mode; and measured temperature of indoor heat exchanger
under heating mode.
1) Cooling overload
a.If T tube≤52
o
C, the unit will return to its original operation state.
b.If T tube≥55
o
C, frequency rise is not allowed.
c.If T tube≥58
o
C, the compressor will run at reduced frequency.
d.If T tube≥62
o
C, the compressor will stop and the indoor fan will run at preset speed.
2) Heating overload
a.If T tube≤50
o
C, the unit will return to its original operation state.
b.If T tube≥53
o
C, frequency rise is not allowed.
c.If T tube≥56
o
C, the compressor will run at reduced frequency.
d.If T tube≥60
o
C, the compressor will stop and the indoor fan will blow residue heat and then stop.
②
Exhaust temperature protection of compressor
a.If exhaust temperature ≥98
o
C, frequency is not allowed to rise.
b.If exhaust temperature ≥103
o
C, the compressor will run at reduced frequency.
c.If exhaust temperature ≥110
o
C, the compressor will stop.
d.If exhaust temperature ≤90
o
Cand the compressor has stayed at stop for at least 3 minutes, the compressor will resume its operation.
③
Communication fault
If the unit fails to receive correct signals for durative 3 minutes, communication fault can be justified and the whole system will stop.
④
Module protection
Under module protection mode, the compressor will stop. When the compressor remains at stop for at least 3 minutes, the compressor will
resume its operation. If module protection occurs six times in succession, the compressor will not be started again.
⑤
Overload protection
If temperature sensed by the overload sensor is over 115
o
C, the compressor will stop and the outdoor fan will stop with a time lag of 30
seconds. If temperature is below 95
o
C, the overload protection will be relieved
o
C.
⑥
DC bus voltage protection
If voltage on the DC bus is below 150V or over 420V, the compressor will stop and the outdoor fan will stop with a time lag of 30 seconds.
When voltage on the DC bus returns to its normal value and the compressor has stayed at stop for at least 3 minutes, the compressor will
resume its operation.
⑦
Faults of temperature sensors
Designation of sensors
Faults
Indoor ambient temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds
Indoor tube temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds
Outdoor ambient temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds
Outdoor tube temperature
The sensor is detected to be open-circuited or short-circuited for successive 30
seconds, and no detection is performed within 10 minutes after defrost begins.
Exhaust
After the compressor has operated for 3 minutes, the sensor is detected to be
open-circuited or short-circuited for successive 30 seconds.
Overload
After the compressor has operated for 3 minutes, the sensor is detected to be
open-circuited or short-circuited for successive 30 seconds.
Zero-crossing inspection circuit
malfunction of the IDU fan motor
Zero-crossing signal is not detected for continuously 3s; Or the interval between
the zero-crossing signals in 3s
＞
25ms (power frequency: 50Hz)
