Chapter 3. Function And Operation Of Pro- Tective Procedures Protection Device Functions And Operations - IVT 09LR-N Service Manual

CHAPTER 3.
12LRN FUNCTION AND OPERATION OF PROTECTIVE PROCEDURES
[1] PROTECTION DEVICE FUNCTIONS AND OPERATIONS
Function
1 Indoor unit fan lock Operation stops if there is no input
of rotation pulse signal from indoor
unit fan motor for 1 minute.
Indoor unit fan rota- Operation stops if rotation pulse
tion speed error signal from indoor unit fan indicates
abnormally low speed (about 300
rpm or slower).
2 Indoor unit freeze Compressor stops if temperature
prevention remains below 0C for 4 minutes.
3 2-way valve freeze Compressor stops if temperature of
prevention outdoor unit 2-way valve remains
below 0C for 10 continuous min-
utes during cooling or dehumidify-
ing operation.
4 Indoor unit heat Operating frequency lowers if
exchanger overheat indoor unit heat exchanger temper-
shutdown ature exceeds overheat tempera-
ture during heating operation.
Compressor stops if indoor unit
heat exchanger temperature
exceeds overheat temperature for
60 seconds at minimum frequency.
Overheat temperature setting value
indoor unit heat exchanger ther-
mistor temperature: about 45 to
54C
5 Outdoor unit heat Operation frequency lowers if out-
exchanger overheat door unit heat exchanger tempera-
shutdown ture 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.
6 Compressor dis- Operating frequency lowers if tem-
charge overheat shut- perature of compressor chamber
down thermistor (TH1) falls below about
110C.
Compressor stops if temperature of
compressor chamber thermistor
(TH1) remains at about 110C (for
120 seconds in cooling operation,
or 60 seconds in heating operation)
at minimum frequency.
7 Dehumidifying opera- Compressor stops if outside air
tion temporary stop temperature thermistor is lower
than about 16C during dehumidify-
ing operation.
8 DC overcurrent error Compressor stops if DC current of
about 25 A or higher flows in IPM.
9 AC overcurrent error Operating frequency lowers if out-
door AC current exceeds peak con-
trol current value. outdoor stops if
compressor AC current exceeds
peak control current value at mini-
mum frequency.
Operation
Description Detection period
When indoor unit fan is
in operation
When indoor unit fan is
in operation
When in cooling or
dehumidifying opera-
tion
When in cooling or
dehumidifying opera-
tion
When in heating opera-
tion
When in cooling or
dehumidifying opera-
tion
When compressor is in
operation
When in dehumidifying
operation
When compressor is in
operation
When compressor is in
operation
Service Manual
Reset condition
Operation OFF or ON ✩2
Operation OFF or ON ✩2
Automatic reset when
heat exchanger tem-
perature rises above
freeze prevention tem-
perature (2C or
higher)
Automatic reset when
temperature of 2-way
valve rises above
10C.
Automatic reset after
safety period (180 sec).
Automatic reset after
safety period (180 sec).
Automatic reset after
safety period (180 sec).
Automatic reset when
outside air tempera-
ture rises above 16C.
Operation OFF or ON Yes ✩1
Operation OFF or ON Yes ✩1
3 – 1
12LRN
Self-diagnosis result
display
Indoor Indoor Outdoor
unit error unit unit
display
Yes None
Yes None
— None None
None Yes Yes
None Yes Yes
None Yes Yes
None Yes Yes
None Yes Yes
Yes Yes
Yes Yes