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CHAPTER 3. FUNCTION AND OPERATION OF PROTECTIVE PROCEDURES
[1] PROTECTIVE FUNCTIONS AND OPERATIONS
NO. Function Operation
Description Detection time Restart condition Restart
time
In
door
Out
door
1 DC over current
Compressor is stopped if a current approxi-
mately 24A or more flows in the power tran-
sistor module.
During compres-
sor operation
Automatically restarts
after safety time (180
seconds)
4 times Yes Yes
2 AC over current
Lowers the operating frequency if the com-
pressor AC current exceeds set value
(16.0A). Stops the compressor if the current
exceeds at minimum frequency.
During compres-
sor operation
Automatically restarts
after safety time (180
seconds)
4 times Yes Yes
3
Compressor over-
heat prevention con-
trol
Lowers the operating frequency if the tem-
perature of the compressor thermistor (TH1)
rises above 108°C. Compressor is stopped if
the thermistor stay above 108°C for 2 min-
utes at minimum frequency.
During compres-
sor operation
Automatically restarts
after safety time (180
seconds)
No limit No No
4
Compressor high
temperature error
Compressor is stopped if the compressor
thermistor is above 113°C (Or when TH1
shorts)
During compres-
sor operation
Automatically restarts
when thermistor (TH1)
temperature falls below
99°C (approximately 30
minutes)
4 times Yes Yes
5
Outdoor heat
exchanger overheat
prevention control
Lowers the operating frequency if the tem-
perature of the outdoor heat exchanger rises
above 57°C during cooling. Stops the com-
pressor if the temperature stays above 57°C
for 2 minutes at minimum frequency
During compres-
sor operation
Automatically restarts
after safety time (180
seconds)
No limit No No
6 Thermistor short
Compressor ia stopped, if heat exchanger or
outdoor thermistor shorts. Close the expan-
sion valve of the corresponding room, if
some suction thermistor shorts.
When the room
is activated turns
ON and the com-
pressor starts.
Operation OFF 1 time Yes Yes
7 Thermistor open
Compressor is stopped, if compressor or
heat exchanger or outdoor thermistor opens.
Close the expansion valve of the corre-
sponding room, if some suction thermistor
shorts. opens.
When the room
turns ON and the
compressor
starts.
Operation OFF 1 time Yes Yes
8
AC abnormal cur-
rent
Compressor is stopped, if the operating fre-
quency is above 70Hz and the compressor
current is below 0.8A.
During compres-
sor operation
Automatically restarts
after safety time.(180
sec.)
4 times Yes Yes
9 Serial signal error
INDOOR
If open, while timer LED blinks, operation is
continued. If short, operation is continued.
OUTDOOR
Closes the expansion valve of the corre-
sponding room if the outdoor unit does not
receive a serial signal from one or more
indoor unit for 30 seconds.
Compressor is stopped, if the outdoor unit
does not receive a serial signal from all
indoor units.
During operation
Automatically restarts
as soon as the serial
communication
becomes possible.
No limit Yes Yes
10
Miswiring check
error
Compressor is stopped, and miswiring check
operation ends.
During miswiring
operation
Miswiring check opera-
tion will not restart
automatically.
4 times Yes Yes
11
Indoor heat
exchanger overheat
prevention control
Lowers the operating frequency if the tem-
perature of any of indoor heat exchanger
rises high temperature during heating.
Stops the compressor if the temperature stay
high for 2 minutes at minimum frequency.
During compres-
sor operation
Automatically restarts
after safety time.(180
sec.)
No limit No No
12
Power factor mod-
ule (Active Filter)
over voltage error
Compressor stops if DC voltage is 450V or
higher.
During compres-
sor operation
Automatically restarts
after safety time.(180
sec.)
4 times Yes Yes
13
Power factor mod-
ule (Active Filter)
low voltage error
Compressor stops if DC voltage is 280V or
lower.
During compres-
sor operation
Automatically re-starts
after safety time.(180
sec.)
4 times Yes Yes
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