Panasonic Inverter Air Conditioner R410A Technical Data And Service Manual

							2-1 Room Temperature  Control .......................................................................................... 2-2
2-2 Cold Draft Prevention (Heating Cycle) ........................................................................ 2-4
2-3 Automatic Fan Speed (Indoor Unit) ............................................................................. 2-5
2-4 Control Functions ......................................................................................................... 2-6
2-5 Outdoor Unit Control PCB ........................................................................................... 2-9
2-6 Outdoor Unit Control PCB (CR-CH4272R) ................................................................2-10
2. PROCESSES AND FUNCTIONS
2-1
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							2-2
2. Processes and functions
Fig. 1
(THERMO.  OFF)
(THERMO.  ON)ROOM TEMP.
THERMO.  ON
5 MINUTES MORE THAN
5 MINUTES 3 MINUTES SET TEMP
COMPRESSOR
OUTDOOR FAN
(H   OR  M)
INDOOR FANF F O F F O
F F O F F O
1
1.  Refer  to  2-4  Outdoor Fan Speed ControlMORE THAN
3 MINUTES MORE THAN
5 MINUTES 
N O N O N O
N O N O N O
SET SPEED T+2°F
T–2°F .  T °F BODY SENSOR
1133_THS_I
THERMO.  OFF
Chart Summary and Explanations
Once the compressor starts, it keeps running for 5 minutes.
Once the compressor stops, it will not start running again for 3 minutes.
If you change the operation mode (HEAT, COOL or FAN) during the heating cycle, the
control circuit stops the compressor for 3 minutes.
For 5 minutes after the compressor is first turned on, and for 3 minutes after it is turned off, 
the compressor is not controlled by the room sensor.
Thermo ON:When room temperature rises 2 F (4F when set on body sensor) above
the set temperature T, (T+2F or T+4F when set on body sensor):
CompressorON
Thermo OFF: When the room temperature is –2F below the set temperature T:
CompressorOFF
2-1 Room Temperature  Control
The unit adjusts room temperature by turning the outdoor unit’s compressor ON and OFF.
This process is controlled by the thermostat located in the remote control unit.
The figures on this and the next pages show how each part of the system performs when the
room temperature changes and the thermostat activates the compressor to start (thermo ON) or
stop(thermo OFF). Fig. 1 shows about the cooling cycle, and Fig. 2 shows about the heating
cycle.
(A) Cooling
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							2-3
2. Processes and functions
Fig. 2
THERMO.  ON
THERMO.  ON
+2°F
F F O F F O 2
1.  Refer  to  2-4  Outdoor Fan Speed Control OFF
SET SPEED
N O N O N O
ON (REVERSING CYCLE)
ON TEMP.
OPERATION REMOTE CONTROL 
SENSOR
(Only for wireless 
remote controller)
BODY SENSOR
OFFOFF SET SPEED SET SPEED 3 SECONDSON OFF ONMORE THAN
3 MINUTES
OFF
ON OFFON OFF ON OFF OFF ON3 MINUTESMORE THAN
5 MINUTES 5 MINUTESTHERMO.  ON
THERMO.  ON THERMO.  ON THERMO.  ON
2.  Refer  to  2-2  Cold Draft Prevention (Heating) BUTTONCOIL (4-WAY) SOLENOID
E2
TEMP. COIL EXCH. INDOOR HEAT STANDBY2
INDOOR FAN1
OUTDOOR FAN
(H OR M)COMPRESSORSET. +2°F
SET. –2°F
–2°F SET TEMP.+7°F SHIFTTHERMO.  OFF
THERMO.  OFF
OFF
(88°F)
81°F
77°F
1134_THS_I
THERMO.  OFF
THERMO.  OFF
LL
LL
LL LL
SETTING TEMP.
SET TEMP. 
Chart Summary and Explanations
Once the compressor starts, it keeps running for 5 minutes.
Once the compressor stops, it will not start running again for 3 minutes.
If you change the operation mode (HEAT,COOL or FA N) during the heating cycle, the
control circuit stops the compressor for 3 minutes.
For 5 minutes after the compressor is first turned on, and for 3 minutes after it is turned off,
the compressor is not controlled by the room sensor.
When set on remote control sensor
Thermo ON: When room temperature is –2F below the set temperature T.
Compressor  ON
Thermo OFF: When the room temperature is 2F above the set temperature T, (T+2 F)
Compressor    OFF
When set on body sensor
NOTE: In case of Body sensor, operating temperature is shifted to setting temperature +7F.
(B) Heating
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							2-4
2. Processes and functions
Fig. 3
92
88
81
77
50
SET
FA N
SPEEDAUTO  OR  H
M
L LL LL/OFF LL L L LLL LL/OFF LL L M M LL LL/OFF LL L M HMAX.  6  MINUTES
“STANDBY”
INDICATOR INDOOR  UNIT
COIL TEMP.
E2 (°F)
LL= Very low speed
L= Low speedM= Medium speed
H= High speed “STANDBY” APPEARS
1135_THS_I
Chart Summary and Explanations
The main idea of this chart is to show that the indoor fan speed increases and gets closer to
the set fan speed as the coil temperature E2 rises.
The indoor unit fs coil temperature is taken from sensor E2 located in the middle of the indoor
heat exchange coil.
The dotted line shows that the indoor fan motor is OFF.  When the temperature at sensor E2
falls below 50F, the indoor fan motor stops running.
2-2 Cold Draft Prevention (Heating Cycle)
The cold draft prevention function controls indoor fan speed so a strong draft of cold air will
not blow out before the indoor heat exchange coils have warmed up.
STANDBY shows on the remote controller when the indoor fan speed is LL (very low)
or OFF. This condition occurs in the following 3 cases:
 During Thermo OFF (refer to 2-1 B. Room Temperature Control, Heating)
 During the defrosting operation (refer to 2-10 Defrosting Control, Heating)
 Until either the coil temperature E2 reaches 81°F or when a maximum of 6 minutes
has past.
The indoor fan motor operates in L instead of LL for 3 seconds as it starts to give the
fan an initial boost.
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							2-5
2. Processes and functions
Fig. 4
INDOOR FAN
SPEED
L H
MMH
1923_M_S
ROOM TEMP.
(deg)
SET TEMP.+3
+2
+1
H
M: High
: MiddleL: Low
Chart Explanations and notes
When the fan speed changes, it keeps the speed step for at least 3 minutes, even if the
temperature changes to another speed step during the time.
Fig. 5
INDOOR FAN
SPEED H
L MMH
1924_M_S
ROOM TEMP. 
(deg)
SET TEMP.
–2
–4
H
M: High
: MiddleL : Low
Chart Explanations and notes
When the fan speed changes, it keeps the speed step for at least 1 minute, even if the
temperature changes to another speed step during the time.
2-3 Automatic Fan Speed (Indoor Unit)
By pressing the FAN SPEED button on the remote controller, the fan speed can be set at one of
four steps: AUTO., HI., MED., or LO. When set at AUTO. the indoor unit fan speed will be
automatically adjusted to the room temperature as the two charts shown below.
(A) Cooling
(B) Heating
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							2-6
2. Processes and functions
124 142
2-4 Control Functions
Electronic control valve control
Opening of the electronic control valve is controlled so
that the appropriate operating conditions are maintained,
based on the signal from each sensor (discharge
temperature [TD], intake temperature [TS], outdoor heat
exchanger temperature [C1], and indoor heat exchanger
temperature [E1, E2]).
Discharge temperature release control
(1) This control lowers the operating frequency of the
compressor when electronic control valve control is
unable to maintain the appropriate operating
conditions because the discharge temperature fails
to decline or because there is a sudden increase in
the discharge temperature.
(2) If the discharge temperature exceeds 232°F, the
compressor is stopped and then restarted. (Error
count = 1)
(3) The error count is cleared when operation has
continued for 10 minutes after the compressor was
restarted.
(4) If (2) repeats 4 times without the error count being
cleared (error count = 4), alarm P03 occurs.
Current release control
The compressor operating frequency is controlled so
that the current that is input to the inverter compressor
does not exceed the designated value (control value).
Outdoor unit fan control
1. Cooling fan control
(1) The outdoor unit fan minimum speed and maximum
speed are determined according to the outdoor air
temperature and the operating frequency. The
speed is controlled in stages between the minimum
speed and maximum speed, based on the outdoor
heat exchanger temperature (C2) at that time.
(2) For 60 seconds after start, the outdoor unit fan
operates at maximum speed, as determined by the
outdoor air temperature and operating frequency at
that time. Subsequently, the fan operates at low
speed until the outdoor heat exchanger temperature
(C2) rises.
(3) If the discharge temperature (TD) sensor is
abnormal or has become disconnected, the fan will
not operate and a protective device is activated.
2. Heating fan control
(1) The outdoor unit fan minimum speed and maximum
speed are determined according to the outdoor air
temperature and operating frequency. The speed is
controlled in stages between the minimum speed
and maximum speed, based on the outdoor heat
exchanger temperature (C1) at that time.(2) If the outdoor heat exchanger temperature (C1) is
75°F or higher continuously for 5 minutes, fan
operation may stop (same conditions as when the
thermostat is OFF). In this case, the fan will restart
after 3 minutes.
(3) This control is not performed during the 3 minutes
after start, for 1 minute after defrost ends, and
while defrost is in progress.
Coil heating control
(1) This control applies current to the coil of the
stopped compressor to heat the compressor in
place of the crank case heater.
(2) When the discharge temperature (TD) is less than
77°F, the current application judgment is made
based on the outdoor air temperature (TO).
 Current application starts when the outdoor air
temperature drops to 59°F or below.
 Current application stops when the outdoor air
temperature rises above 64°F.
Control for prevention of short intermittent operation
In order to protect the compressor, this control does not
allow the compressor to be stopped for 10 minutes after
operation starts, even if the thermostat OFF signal is
received from the indoor unit.
Control for prevention of high cooling loads
This control reduces abnormal high-pressure increases
during cooling operation.
(1) If MAX (C1, C2) (C1 & C2: outdoor heat exchanger
temperature) is less than 124°F, the compressor
performs normal operation.
(2) If MAX (C1, C2) is 124°F or higher and less than
142°F, the revolution of the compressor is
controlled to prevent the high pressure being
increased.
(3) If MAX (C1, C2) is 142°F or higher, the compressor
stops once. The compressor restarts three times,
and if the temperature dose not decrease to less
than 142°F, the alert P20 is displayed.
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							2-7
2. Processes and functions
36
(36, 48 types)
Overcurrent protection control
(1) If the overcurrent protection circuit detects
abnormal current, the compressor is stopped. (Error
count = 1.) The compressor then restarts after 3
minutes.
(2) If compressor start/stop is repeated 4 times (error
count = 4), alarm P26, P29 or H01 (count = 2
in this case only) occurs. Operation stops and does
not restart.
Current release value shift control
(1) This control is intended to improve compressor
reliability by preventing continuous high-frequency
operation under overload conditions when the
outdoor air temperature is high, and by preventing
intermittent operation through control for
prevention of high cooling loads.
(2) The control value for current release control is
corrected according to the outdoor air temperature
(TO).
Depending on the temperature, the control value is
lowered to 50 – 90% for cooling operation, and to
60 – 98% for heating operation.
Freeze prevention (low-temperature release) control
The below control is performed during cooling operation
(including dehumidifying operation), using whichever of
the indoor heat exchanger temperatures (E1 or E2) is
lower. (See the figure below.)
(1) If a temperature in the J area (operating
frequency reduction and thermostat OFF area) is
detected for 6 minutes, the compressor operating
frequency is reduced. The compressor operating
frequency is reduced every 30 seconds as long as
the temperature remains within this area.
(2) If the temperature is in the K area (operating
frequency increase-prohibit area), the compressor
operating frequency is maintained.
(3) If the temperature is in the H area (operating
frequency control area), and the outdoor air
temperature is less than 90°F, the compressor
maximum operating frequency is limited according
to the indoor unit fan speed.
(4) If the temperature is in the I area (normal
operating area), the compressors operate normally.
(5) If the temperature is continuously in the J area
and the compressor operating frequency reaches 0,
then temperature A (temperature for changing from
J area to H area) is raised from 41°F to 46°F,
and operation continues with the thermostat OFF
until the temperature reaches the H area.
Heating high-load control
The below control is performed during heating operation,
based on the indoor heat exchanger temperature MAX
(E1,E2).
(1) If the temperature is in the M area (operating
frequency reduction and thermostat OFF area), the
compressor operating frequency is reduced.
The compressor operating frequency is reduced
every 30 seconds as long as the temperature
remains within this area.
(2) If the temperature is continuously in the M area,
the thermostat turns OFF.
(3) If the temperature is in the N area, operating
frequency increases are prohibited.
(4) If the temperature is in the L area, the operating
frequency is raised to the original frequency (the
frequency prior to frequency reduction) by 6 Hz
every 60 seconds.
* When the compressor turns ON and the E2
temperature rises, the temperature at which the
M area is first entered is 124°F (36, 42 types) 
or higher than 129°F (26 type).
If the E1, E2 temperature subsequently falls to
the L area, the temperature for entering the M
area is raised to 126°F (36, 42 types) or 133°F
(26 type).
However if the E1, E2 temperature falls to the L
area and falls below 86°F, then the temperature for
entering the M area is changed back to 124°F
(36, 42 types) or 129°F (26 type).
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							2-8
2. Processes and functions
1





2
3Defrost control
Defrost sequence
Heating operation 
(25-minute mask)
Frost detection
Defrost start 
(reverse cycle defrost)
Defrost in progress
Defrost cancel
Start-up operationOperating frequency: 61.8 Hz
Outdoor unit fan: OFF
Electronic control valve: step 300 
4-way valve: OFF
Indoor unit fan: OFF
Defrost control
(1) Frost detection
1. Outdoor heat exchanger temperature (C1) method (15-minute mask after operation start)
2. Outdoor air temperature is 7°F or above and outdoor heat exchanger temperature (C1) of 0°F or below is
detected continuously for 20 seconds.
3. Outdoor air temperature is below 7°F and outdoor heat exchanger temperature (C1) of below (outdoor air
temperature -10)°F is detected continuously for 20 seconds.
(2) Defrost cancel
 Defrost end conditions
1. Outdoor heat exchanger temperature (C1) rises to 54°F or higher.
2. Outdoor heat exchanger temperature is 45°F or higher continuously for 1 minute.
3. Defrost time of 10 minutes has elapsed.
(3) Startup operation
After defrost ends, the compressors and outdoor unit fan stop for approximately 40 seconds, then operation begins
in heating mode.
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							2-9
2. Processes and functions
Fan motor plug (CN004)EEPROM IC MDC Heat exchanger temperature (C2) sensorHeat exchanger temperature (C1) sensorSuction temperature (TS) sensor
Outdoor air temperature (TO) sensor
Compressor discharge temperature (TD) sensor
Refrigerant recovery switch 
(S005)
Quiet mode plug (CN028)
EXCT plug (CN026)
Automatic address 
setting switch (S001)
Snowfall sensor
Cooling test
Test pin (CN036)
Operation circuit fuse 
(F002)
LED 1, 2 Serial 1 plug
Terminal plug (CN015)
Serial 2 plug
If the operation circuit fuse 
(F002) has blown, 
determine and correct the 
cause for the blown fuse, 
then change the socket 
from the serial 1 plug to 
the serial 2 plug.
Position detection plug 
(CN003) Refrigerant System 
address switch (S002) 
Refrigerant System 
address switch (S003) 
Power LED (D115)
2-5 Outdoor Unit Control PCB
(1) Layout Diagram (CR-CH4872R)
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							2-10
2. Processes and functions
Push-button switch (black): Automatic address setting switch
 If the system address switch (S002: set to 0 at time of shipment) setting is other than
0 (central control), press this switch once to automatically set the addresses at all
indoor units which are in the same system, and are connected to that outdoor unit.
During automatic address setting, the 2 LEDs (red) on the outdoor unit control PCB
blink alternately.
(Pressing this switch again stops automatic address setting.)
 If automatic address setting is currently in progress at another system that is subject
to central control, only LED 1 on the outdoor unit control PCB blinks to indicate that
automatic address setting is in progress at another unit. If automatic address setting is
in progress at another unit, automatic address setting cannot be started at this unit,
even if S001 is pressed.
Rotary switch (10 positions, black): System address setting switch
 This switch is set to 0 (1 system control) at the time of shipment. However the address
for each system must be set when multiple systems are controlled or when central
control is used. (Figure 1)
 If the system address is set to 0, automatic address setting is started when the power is
turned ON. Therefore it is not necessary to use switch SW01 and perform automatic
address setting in the case of single or simultaneous-operation multi control of a single
system.
 When using central control for multiple systems, a maximum of 30 systems (maximum
64 units) can be connected. In the case of group control or central control, set the sys-
tem address to a setting other than 0 (1 or above).
 If the number of systems is greater than 9, this switch can be used in combination with
DIP switch S003 to set up to 30 systems. The setting can be made as high as 39,
however all settings above 30 are handled as 30 for control. (For details, refer to Table 1.)
 If system addresses are duplicated (the same address exists more than once), LED 1 on
the outdoor unit control PCB lights up, and alarm L04 is displayed on the remote con-
troller.
DIP switch (2P, blue): System address 10s-digit and 20s-digit place setting switch
 When setting 10 systems or more, set this switch in combination with S002.
 For 10 – 19 systems, set 1P (10s-digit place) to ON.
 For 20 – 29 systems, set 2P (20s-digit place) to ON, and set 1P (10s-digit place) to OFF.
 For 30 systems, set both 1P (10s-digit place) and 2P (20s-digit place) to ON. (For details,
refer to Table 1.)
Refrigerant recovery switch (red button switch)
 Press this switch to perform refrigerant recovery control using cooling operation. The
indoor unit fan will operate at HIGH and 55 Hz for a maximum of 10 minutes. When
refrigerant recovery is completed, close the valves and press this switch to stop the
operation.
2P plug (red): Pin used for PCB inspection at the factory
3P plug (red): Can be used for demand control
 The operating ranges are shown in the table.
Test (CN036)
EXCT (CN026)S001
S002
S003
S005
2P and 3P 1P and 3POperating
range
0
0
1
10
1
0
1normal (at shipment
from factory)
rated capacity
70%
0%Short-circuited  
2-6 Outdoor Unit Control PCB (CR-CH4272R)
(1) Explanation of Functions
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