AYXP12JHRN
3 – 1
AYXP12JHRN
Service Manual
CHAPTER 3.
FUNCTION AND OPERATION OF PROTECTIVE PROCEDURES
[1] PROTECTION DEVICE FUNCTIONS AND OPERATIONS
Function
Operation
Self-diagnosis
result display
Description
Detection period
Reset condition
Indoor
unit
error
display
Indoor
unit
Outdoor
unit
1
Indoor unit fan lock
Operation stops if there is no
input of rotation pulse signal from
indoor unit fan motor for 1 minute.
When indoor unit fan
is in operation
Operation OFF or ON
✩
2
Yes
None
Indoor unit fan rota-
tion speed error
Operation stops if rotation pulse
signal from indoor unit fan indi-
cates abnormally low speed
(about 300 rpm or slower).
When indoor unit fan
is in operation
Operation OFF or ON
✩
2
Yes
None
2
Indoor unit freeze
prevention
Compressor stops if temperature
remains below 0
°
C for 4 minutes.
When in cooling or
dehumidifying opera-
tion
Automatic reset when
heat exchanger tem-
perature rises above
freeze prevention
temperature (2
°
C or
higher)
—
None
None
3
2-way valve freeze
prevention
Compressor stops if temperature
of outdoor unit 2-way valve
remains below 0
°
C for 10 continu-
ous minutes during cooling or
dehumidifying operation.
When in cooling or
dehumidifying opera-
tion
Automatic reset when
temperature of 2-way
valve rises above
10
°
C.
None
Yes
Yes
4
Indoor unit heat
exchanger over-
heat shutdown
Operating frequency lowers if
indoor unit heat exchanger tem-
perature exceeds overheat tem-
perature during heating
operation.
Compressor stops if indoor unit
heat exchanger temperature
exceeds overheat temperature for
60 seconds at minimum fre-
quency.
Overheat temperature setting
value indoor unit heat exchanger
thermistor temperature: about 45
to 54
°
C
When in heating
operation
Automatic reset after
safety period (180
sec).
None
Yes
Yes
5
Outdoor unit heat
exchanger over-
heat shutdown
Operation frequency lowers if out-
door unit heat exchanger temper-
ature exceeds about 55
°
C during
cooling operation.
Compressor stops if outdoor unit
heat exchanger temperature
exceeds about 55
°
C for 120 sec-
onds at minimum frequency.
When in cooling or
dehumidifying opera-
tion
Automatic reset after
safety period (180
sec).
None
Yes
Yes
6
Compressor dis-
charge overheat
shutdown
Operating frequency lowers if
temperature of compressor
chamber thermistor (TH1) falls
below about 110
°
C.
Compressor stops if temperature
of compressor chamber ther-
mistor (TH1) remains at about
110
°
C (for 120 seconds in cooling
operation, or 60 seconds in heat-
ing operation) at minimum fre-
quency.
When compressor is
in operation
Automatic reset after
safety period (180
sec).
None
Yes
Yes
7
Dehumidifying oper-
ation temporary
stop
Compressor stops if outside air
temperature thermistor is lower
than about 16
°
C during dehumidi-
fying operation.
When in dehumidify-
ing operation
Automatic reset when
outside air tempera-
ture rises above
16
°
C.
None
Yes
Yes
8
DC overcurrent
error
Compressor stops if DC current
of about 25 A or higher flows in
IPM.
When compressor is
in operation
Operation OFF or ON
Yes
✩
1
Yes
Yes
