28
Technical Information
Service Manual
2.Protection
a. In cooling operation, protection is the sam e 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
Overload protection
T
tube
: measured temperature of outdoor heat exchanger under cooling mode; and measured temperature of indoor heat
exchanger under heating mode.
Test the temperature of outdoor heat exchanger when cooling; test the temperature of indoor heat exchanger when heating.
a.When Ttube
≦
T1, resume original operation status;
b.When Ttube≥T2, prohibit increasing the frequency;
c.When Tube≥T3, compressor operates by decreasing frequency;
d.When Ttube≥T4, compressor stops operation;
When cooling or drying: T1=52
，
T2=55
，
T3=58
，
T4=62
；
When heating: T1=50
，
T2=53
，
T3=56
，
T4=60
；
Exhaust temperature protection of compressor
If exhaust temperature 98
, frequency is not allowed to rise.
If exhaust temperature 103
, the compressor will run at reduced frequency.
If exhaust temperature 110
, the compressor will stop.
If exhaust temperature 90
and the compressor has stayed at stop for at least 3 minutes, the compressor will resume its
operation.
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.
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.
Overload protection
If temperature sensed by the overload sensor is over 115 , the compressor will stop and the outdoor fan will stop with a
time lag of 30 seconds. If temperature is below 95
, the overload protection will be relieved.
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.
Faults of temperature sensors
(5) AUTO Mode
a. When Tamb.≥26
ć
, the unit will operate under cooling mode, while the implied setting temperature is 25
ć
.
b. When Tamb.≤22
ć
, the heat pump unit will operate under heating mode, while the implied setting temperature is 20
ć
; the cooling
only unit will operate under fan mode, while the displaying setting temperature is 25
ć
.
c. When 23
ć
≤Tamb.25
ć
, the unit will operate as previous mode. If it is the first time energized, the unit will operate under fan mode.
d. When the unit is operating under auto mode, the compressor frequency is the same as cooling/heating mode when the unit is under
cooling/heating operation.
Note: T
indoor amb.
indicated in 1 and 2 refers to, under initially heating mode, the indoor ambient temperature before the
command to start the compressor is performed according to the program, or after the unit is withdrawn from defrost, the
indoor ambient temperature before the defrost symbol is cleared.
Total current up and frequency down protection
If the total current I
total
W, frequency rise will be allowed; if I
total
X, frequency rise will not be allowed; if I
total
Y, the
compressor
will run at reduced frequency; and if I
total
Z, the compressor will stop and the outdoor fan will stop with a time lag of 30s.
(4) Fan Mode
Under the mode, the indoor fan will run at preset speed and the compressor, the outdoor fan, the four-way valve and the
electric heater will stop.
Under the mode, temperature can be set within a range of 16 - 30
.
