Service manual

146
a. Under AUTO mode, if T
amb
.≥T
preset
is detected, the unit will select to run under cooling mode, in which case implicit
preset temperature is 25ć; if T
amb
.≤T
preset
-2ć, the compressor will stop, the outdoor fan will stop with a time lag of 1
minute, and the indoor fan will run at preset speed; and if T
preset
–(-2ć)< T
amb
.< T
preset
, the unit will remain at its original
state.
b. Under AUTO mode, if T
amb
. ≤T
preset
+2ć is detected, the unit will select to run under heating mode, in which case
implicit preset temperature is 18ć; if T
amb
.≥T
preset
+5ć, the compressor will stop, the outdoor fan will stop with a time lag
of 1 minute, and the indoor fan will run under the mode of residue heat blowing; and if T
preset
+2ć< T
amb
.< T
preset
+5ć, the
unit will remain at its original state. The cooling-only unit will run under fan mode.
c. Under AUTO mode, if 20ć< T
amb
.< 25ć, the unit will remain at its original state.
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
ķ
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
≤52ć, the unit will return to its original operation state.
b. If T
tube
≥55ć, frequency rise is not allowed.
c. If T
tube
≥58ć, the compressor will run at reduced frequency.
d. If T
tube
≥62ć, the compressor will stop and the indoor fan will run at preset speed.
2) Heating overload
a. If T
tube
≤52ć, the unit will return to its original operation state.
b. If T
tube
≥55ć, frequency rise is not allowed.
c. If T
tube
≥58ć, the compressor will run at reduced frequency.
d. If T
tube
≥62ć, the compressor will stop and the indoor fan will blow residue heat and then stop.
ĸ
Exhaust temperature protection of compressor
If exhaust temperature ≥98ć, frequency is not allowed to rise.
If exhaust temperature ≥103ć, the compressor will run at reduced frequency.
If exhaust temperature ≥110ć, the compressor will stop.
If exhaust temperature ≤90ć and the compressor has stayed at stop for at least 3 minutes, the compressor will resume its
operation. 
Ĺ
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.
ĺ
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.
Ļ
Overload protection
If temperature sensed by the overload sensor is over 115ć, the compressor will stop and the outdoor fan will stop with a
time lag of 30 seconds. If temperature is below 95ć, the overload protection will be relieved. 
ļ
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.
Ľ
Faults of temperature sensors
Operation