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3-3
12PHR-N
Function
Operation
Self-diagnosis result
display
Description
Detection period
Reset condition
Indoor
unit error
display
Indoor
unit
Outdoor
unit
23
Outdoor unit
discharge
thermistor open-
circuit error
Compressor stops if there is
open-circuit in outdoor unit
discharge thermistor (TH1).
At compressor startup
Operation OFF or ON
Yes
☆
1
Yes
Yes
24
Serial signal
error
Compressor stops if outdoor
unit cannot receive serial
signal from indoor unit for 30
seconds.
When in operation
Reset after reception of
serial signal
None
None
None
25
Compressor
startup
error
Compressor stops if
compressor
At compressor startup
Operation OFF or ON
Yes
☆
3
Yes
Yes
26
Compressor
rotation error (at
120° energizing)
Compressor stops if there is no
input of position detection sig-
nal from compressor or input is
abnormal.
Compressor operating
at 120° energizing
Operation OFF or ON
Yes
☆
3
Yes
Yes
27
Outdoor unit DC
fan error
Operation stops if there is no
input of rotation pulse signal
from outdoor unit fan motor for
30 seconds.
When outdoor unit fan
is in operation
Operation OFF or ON
Yes
☆
1
Yes
Yes
28
PAM over
voltage error
Compressor stops if DC
voltage is 400 V or higher.
When in operation
Operation OFF or ON
Yes
☆
2
Yes
Yes
29
PAM clock error
When power source frequency
cannot be determined (at
startup), or when power source
clock cannot be detected for 1
continuous second (at startup).
At compressor startup,
when in operation
Compressor continues
operation without
stopping.
None
Yes
Yes
☆
1—A single error judgment results in the display of the indoor unit error (complete shutdown).
☆
2—The outdoor unit restarts four times before the indoor unit error is displayed (complete shutdown).
☆
3—The outdoor unit restarts eight times before the indoor unit error is displayed (complete shutdown).
[2] AIR CONDITIONER OPERATION IN THERMISTOR ERROR
1. Indoor unit
Item
Mode
Control operation
When resistance
is low (temperat-
ure judged higher
than actual)
Short-circuit
When resistance
is high (temperat-
ure judged lower
than actual)
Open-circuit
Room temperature
thermistor (TH1)
Auto
Operation mode
judgment
Cooling mode is
activated even if
room temperature
is low.
Cooling mode is
activated in most
cases.
Heating mode is
activated even if
room temperature
is high.
Heating mode is
always activated.
Cooling
Frequency control
Room becomes too
cold.
Air conditioner
operates in full
power even when
set temperature is
reached.
Room does not
become cool.
Compressor does
not operate.
Dehumidifying
Room temperature
memory Frequency
control
Normal operation.
Room temperature
is stored in memory
as 31.0°C, and
compressor does
not stop.
Normal operation.
Room temperature
is stored in memory
as 18.5°C, and
compressor does
not operate.
Heating
Frequency control
Room does not
become warm.
Frequency does
not increase above
30 Hz (40 Hz).
Room becomes too
warm.
AIR CONDI-
TIONER operates
in full power even
when set temperat-
ure is reached.
Heat exchanger
thermistor (TH2)
Cooling
Dehumidifying
Freeze prevention
Indoor unit evapor-
ator may freeze.
Indoor unit evapor-
ator may freeze.
Compressor stops
occasionally.
Compressor does
not operate.
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