Panasonic Cs Kexxnb4x Cz 18bt1u Service Manual

							< Clock display >
Test run mode
Self-diagnostics mode
9.  TROUBLESHOOTING (BEFORE CALLING FOR SERVICE)
9-1.  Precautions before Performing Inspection or Repair
NOTE
After checking the self-diagnostics monitor, turn the power OFF before starting inspection or repair.
High-capacity electrolytic capacitors are used inside the outdoor unit controller (inverter). They retain an electrical charge 
(charging voltage DC 310V) even after the power is turned OFF, and some time is required for the charge to dissipate. Be 
careful not to touch any electrified parts before the controller LED (red) turns OFF.
If the outdoor controller is normal, approximately 30 seconds will be required for the charge to dissipate. However, allow at 
least 5 minutes for the charge to dissipate if there is thought to be any trouble with the outdoor controller.
1: If the operation lamp blinks every 0.5 seconds immediately when the 
power is turned ON, there is an external ROM (OTP data) failure on the 
indoor circuit board, or a ROM socket insertion problem, or the ROM 
has not been installed.
2: The failure mode is stored in memory even when the power is not ON. 
Follow the procedure below to perform diagnostics.
9-2.  Method of Self-Diagnostics
Follow the procedure below to perform detailed trouble diagnostics.
PROCEDURE
Step 1: Press and hold the remote controller HIGH POWER button and 1 
HR TIMER button. Then, press and hold the ACL (reset) button 
with a pointed object such as the tip of a pen. After 5 seconds, 
release ACL button first, then release HIGH POWER and 1 HR 
TIMER buttons, "oP-1" (test run) appears, blinking in the remote 
controller clock display area.
Step 2: Next, press the 1 HR TIMER button once to change the display 
from "oP-1" to "oP-3" (self-diagnostics). (The display continues to 
blink.)
Step 3: Finally press the ON/OFF button to engage self-diagnostics mode. 
•  The self-diagnostics function utilizes the 3 indicator lamps on the main 
unit, in combinations of ON lamps, blinking lamps, and OFF lamps, to 
report the existence of sensor trouble or a protective operation. (The 
lamps blink or remain ON for 5 seconds, then turn OFF for 2 seconds.) 
Self-diagnostics is completed when the buzzer sounds 3 short beeps.
•  A maximum of 3 self-diagnostics reports are displayed, for 5 seconds 
each, beginning with the most recent report. Following this display the 
lamps turn OFF. In order to view the self-diagnostics results again, press 
the ON/OFF button again.
•  The 3 lamps remain OFF if no trouble has occurred.
 After self-diagnostics is completed, be sure to press the 
ACL (reset) button to return to normal mode. The air 
conditioner will not operate if this is not done. After turning on power to the air conditioner, use the remote controller and 
follow the steps below to execute self-diagnostics.
ACL
(Reset)
button 1HR.
TIMER
button ON/OFF
operation
button
HIGH POWER
button
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							  Since the indications cover various units, the corresponding parts listed below may not be  present in some models.
(1) Self-diagnostics Lamps
(1) DRAIN PUMP FAILURE   (2) FS FAILURE  (3) CHOKED DRAIN HOSE
8512-5261-99100-1
REMOTE CONTROL receiver
OPERATION lamp 
TIMER lamp OPERATION button
HIGH POWER lamp
INDOOR UNIT
TIMER
LAMPBLINKING (3 SEC. INTERVAL)FLOAT SWICTH (FS) IS ACTIVED.
.... 
OFF
CODE DIAGNOSIS CONTENTS POSSIBLE MALFUNCTION
ROOM TEMP. SENSOR TROUBLE
I/D HEAT EXCHANGER TEMP. 
SENSOR TROUBLE
COMPRESSOR TEMP. SENSOR  
     TROUBLE
O/D HEAT EXCHANGER TEMP. 
SENSOR TROUBLE
O/D AIR TEMP. SENSOR TROUBLE
I/D-O/D COMMUNICATION
     TROUBLE 
(SERIAL COMMUNICATION
     TROUBLE)
O/D UNIT EXTERNAL ROM
     TROUBLE
CURRENT PEAK CUT HIC CIRCUIT TROUBLE
POWER TR CIRCUIT TROUBLE
PAM CIRCUIT TROUBLE
ACTIVE CIRCUIT TROUBLE
O/D SYSTEM COMM FAILURE,
OLR OPERATION, O/D POWER
OPEN PHASE, O/D FREEZING COMPRESSOR
DISCHARGE TEMP.
OVERHEATING PREVENTION
I/D FAN OPERATION TROUBLE
GAS-LOSS PREVENTION
DC COMPRESSOR DRIVE
   CIRCUIT TROUBLE
O/D DC FAN OPERATION TROUBLE
FREEZING-PREVENTION OPERATION
4-WAY VALVE  SWITCHING
     TROUBLE
ZERO-CROSS TROUBLE O/D CURRENT SENSOR ERROR
.... 
BLINKING.... 
ON
OPERATIONTIMERHIGHPOWER
(1) OPEN OR SHORT CIRCUIT IN SENSOR
(2) POOR CONTACT AT CONNECTOR OR OPEN
    
 CIRCUIT AT TERMINAL PRESS-FIT LOCATION.
(3) I/D PCB FAILURE (I/D = INDOOR)
(1)  OPEN OR SHORT CIRCUIT IN SENSOR
(2)  POOR CONTACT AT CONNECTOR OR OPEN
    
 CIRCUIT AT TERMINAL PRESS-FIT LOCATION
(3) O/D PCB FAILURE (O/D = OUTDOOR)
O/D PCB FAILURE
(1) MIS-WIRING    (2) AC POWER FAILURE    (3) BLOWN FUSE
(4) POWER RELAY FAILURE    (5) I/D OR O/D PCB FAILURE
(6) O/D FAN MOTOR FAILURE    (7) REACTOR FAILURE
(8) HIGH-PRESSURE SW FAILURE   (9) OLR FAILURE   (10) MAGNETIC COIL FAILURE
(1) HIC OR POWER TR FAILURE   (2) O/D FAN NOT OPERATING
(3) INSTANTANEOUS POWER STOPPAGE   (4) SERVICE VALVE NOT OPENED  
(5) O/D FAN BLOCKED   (6) CONTINUOUS OVERLOAD OPERATION  
(7) COMPRESSOR FAILURE   (8) O/D PCB FAILURE
(1) EXTERNAL ROM DATA FAILURE    (2) O/D PCB FAILURE
(1) INSTANTANEOUS POWER STOPPAGE    (2) HIC OR POWER TR FAILURE    
(3) O/D PCB FAILURE
(1) O/D PCB FAILURE
(2) O/D POWER VOLTAGE TROUBLE
(1) ELECTRIC EXPANSION VALVE FAILURE  (2) CHOKED CAPILLARY TUBE
(3) INSUFFICIENT GAS  (4) CONTINUOUS OVERLOAD OPERATION
(5) O/D FAN NOT OPERATING  (6) O/D PCB FAILURE
(1) FAN MOTOR FAILURE    (2) CONNECTOR CONTACT  FAILURE
(3) I/D PCB FAILURE
(1) 4-WAY VALVE FAILURE (HEAT PUMP MODEL ONLY)
(2) O/D PCB FAILURE
(1) SERVICE VALVE NOT OPENED   (2) INSUFFICIENT GAS
(1) OPEN PHASE    (2) O/D PCB FAILURE
(1) FAN MOTOR FAILURE    (2) CONNECTOR CONTACT FAILURE
(3) O/D PCB FAILURE
(1) MIS-WIRING    (2) BLOWN FUSE
(3) POWER RELAY FAILURE    (4) O/D PCB FAILURE
(5) COMPRESSOR FAILURE
(1) I/D FAN SYSTEM TROUBLE    (2) INSUFFICIENT GAS
(3) OPERATION AT LOW TEMPERATURE
S01
S02
S04
S05
S06
S07
E01
E02
E03
E04
E05
E06
E07
E08
E09
E10
E11
E12
E13
INDICATION ON INDOOR UNIT
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							(2) If the self-diagnostics function fails to operate
Check the indoor unit.
Is the fuse blown?
Replace the controller.Replace the circuit
board or the fuse. No indicators illuminate and the 
indoor fan does not rotate.
Check the power voltage. •
•
NormalBlown
9-3. Checking the Indoor and Outdoor Units
(1) Checking the indoor unit
(2) Checking the outdoor unit
 Using the TEST/T-RUN terminalsControl No. Check items (unit operation)
T-RUN : Test run (compressor and fan motor turn ON).
TEST/MV : Compresses time to 1/60th (accelerates 
operation by 60 times faster than normal).
Use the remote controller to operate the
unit in "TEST run" mode. To determine
whether the mode is currently in
"TEST run" mode, check the 3 indicator 
lamps on the unit. If all 3 are blinking,
the current mode is "TEST run."
 If there are no problems with the above, then check the outdoor unit.
1The rated voltage must be present between inter-unit wirings 1 and 2.
Connect a 5 k ohm resistor between inter-unit wirings 2 and 3. When the 
voltage at both ends is measured, approximately 12 to 15V DC must 
be output and the multimeter pointer must bounce once every 8 
seconds.
Or instead of measuring the voltage, you can insert an LED jig and 
check that the LED flickers once every 8 seconds. •
•
Control No. Check items (unit operation)
Apply the rated voltage between outdoor 
unit terminals L and N.
 If there are no problems with the above, then check the indoor unit.
1 The control panel LED (red) must illuminate.
Short-circuit the outdoor unit COM terminal 
to the T-RUN terminal. 2 The compressor, fan motor and 4-way valve must all turn on.•
•
TEST/T-RUN terminals
(TEST)/MV T-RUN COM
 For the "Test run" procedure, refer to the Appendix B "Installation Instructions".
53 
						

							(3) Serial Communication Error Identification Procedure
Refer to "Method of Self-Diagnostics" for the self-diagnostics procedure.
(3-1) Condition: E01< Before the Operation > If the lamps on the main body show the following conditions after the completion of self-diagnostics,
a communication error between the indoor unit and outdoor unit might be considered.
In such a case, identify the breakdown section by using the following procedure.
Troubleshooting Serial Communication
Is the voltage of about DC12V
or more given between the terminals
2 and 3 on the outdoor unit terminal strip
(Serial Communication Line) ?
(Fig. 1)
No
Ye s
1. Turn OFF the power and wait until the power lamp (LED)
  of the outdoor unit controller is turned OFF.
2. Disconnect the cable from the terminal 3 on the indoor unit
  terminal strip.             (Fig. 2)
3. Turn ON the power.
< Convenient Tool for Short-Circuit Work ( for example ) >Alligator Clip
Alligator ClipCable
A
( Continued to the next page A. )B
( Continued to the next page B. )
For terminal strip short circuit work or inter-unit wiring removal, turn off the power to
avoid an electric shock.
Release the terminal strip short circuit after the completion of self-diagnostics.
Do not perform the short-circuit work between any other terminals except for
specified ones on the specified terminal strip. If such work is performed between
the incorrect terminals, the unit might be broken.
Fig. 1Outdoor Unit
Power
124356
123
V+ -
Indoor Unit
Outdoor Unit
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123
V
+
-
Powe r
Indoor Unit
Fig. 2
NOTE
Lamp TimerOperation: Off
: Blinking
Condition
: IlluminatedE01
E12
High Power
CAUTION
WARNING
< Check Items before Troubleshooting Serial Communication Start >
After confirming that the following errors do not exist, start the "Troubleshooting Serial Communication"
in "Condition: E01 and E12".
1.  Mis -wiring (inter-unit cable, etc.)
2.  AC power failure
3. Blown fuse
4.  Power Relay failure
5.  Outdoor Fan Motor failure (defective insulation, etc.) 6.  Reactor failure (defective insulation, etc.) 
 7.  High-Pressure Switch failure
 8.  Overload Relay failure
 9.  Magnetic Coil failure (defective insulation, short-circuit, etc.)
10. Compressor failure (defective insulation, etc.) 
54 
						

							What is the latest self-diagnosis result ?Condition: E12Defect in the outdoor unit
P.C. board.
Condition: E01
Defect or connection error
in the inter-unit cable
Defect in the indoor unit
P.C. board
( Continued from the previous page A. )
A( Continued from the previous page B. )
B
124356
123
Outdoor Unit
Power
Fig. 3 Indoor Unit
124356
123
Outdoor Unit
Powe r
Fig. 4 Indoor Unit
124356
123
Outdoor Unit
Powe r
Fig. 5 Indoor Unit
Condition: E12
Condition: E01
1. Turn OFF the power and wait until the power lamp (LED)
  of the outdoor unit controller is turned OFF.
2. Short-circuit between the terminals 2 and 3 on the outdoor
  unit terminal strip.                                              (Fig. 3)
1. Turn ON the power and operate the system using the
  remote controller or the operation button on the indoor unit.
2. Perform the self-diagnosis five seconds after the operation
 start.
1. Turn off the power and wait until the power lamp (LED)
  of the outdoor unit controller is turned OFF.
2. Remove the short-circuit between the terminals 2 and 3 on
  the outdoor unit terminal strip.
3. Disconnect the cable from the terminal 3 on the indoor unit
  terminal strip.                                                    (Fig. 4)
Short-circuit between the terminals 2 and 3 on the indoor unit
terminal board.                                                     (Fig. 5)
1. Turn ON the power and operate the system using the
  remote controller or the operation button on the indoor unit.
2. Perform the self-diagnosis five seconds after the operation
 start.
What is the latest self-diagnosis result ?
Defect in the indoor unit
P.C. board
Is the voltage of about DC22V to
24V given between the terminals
2 and 3 on the indoor unit terminal strip
(Serial Communication Line) ?
(Fig. 2)
No
Defect or connection error
in the inter-unit cable
Ye s
55 
						

							(3-2) Condition: E12
Troubleshooting Serial Communication
1. Turn off the power and wait until the power lamp (LED)
  of the outdoor unit controller is turned OFF.
2. Disconnect the cable from the terminal 3 on the indoor
  unit terminal strip.                                        (Fig. 7)
Defect in the indoor unit
P.C. board
Defect in the outdoor unit
P.C. board
1. Turn ON the power and operate the system using the
  remote controller or the operation button on the indoor unit.
2. Perform the self-diagnosis five seconds after the operation
 start.
1. Turn off the power and wait until the power lamp (LED)
  of the outdoor unit controller is turned OFF.
2. Disconnect the cable from the terminal 3 on the Outdoor
  unit terminal strip.                                          (Fig. 6)
Defect in the inter-unit
cable
1. Turn ON the power and operate the system using the
  remote controller or the operation button on the indoor unit.
2. Perform the self-diagnosis five seconds after the operation
 start.
Condition: E12Condition: E01
Condition: E01
Condition: E12 What is the latest self-diagnosis result ?
What is the latest self-diagnosis result ?
124356
123
Outdoor Unit
Fig. 6
Powe r
Indoor Unit
124356
123Power
Fig. 7Outdoor Unit
Indoor Unit
56 
						

							[Trouble symptom 3] Motor rotates for some time (several seconds), but then quickly stops, when the indoor unit 
operates.
(There is trouble in the system that provides feedback of motor rotation speed from the 
motor to the indoor unit controller.)
[Trouble symptom 4] Fan motor rotation speed does not change during indoor unit operation.
[Trouble symptom 5] Fan motor rotation speed varies excessively during indoor unit operation.
(Remedy for symptom 3 to 5)
It is not possible to identify whether the trouble is indoor unit controller trouble or motor trouble. 
Therefore, first replace the indoor unit controller, then (if necessary) replace the DC motor.
9-4.  Trouble Diagnosis of Fan Motor
9-4-1.  Indoor Fan Motor
This indoor DC fan motor contains an internal control PCB. Therefore, it is not possible to measure the coil 
resistance, and the following procedure should be used to check the motor.
To perform diagnosis, operate the unit in cooling mode with indoor fan speed "High". Next, make sure that the 
indoor unit receive the signals from the remote controller when the ON/OFF operation button is pressed.
[Trouble symptom 1] The fan does not stop when the unit stops.    Indoor unit controller trouble.
[Trouble symptom 2]  The fan motor does not rotate when the unit is operating.
(Diagnostic procedure)
* Disconnect the motor connectors and measure the voltage at the DC motor connectors on the indoor 
unit controller (3 locations).
(Diagnostic results)
All of the above measured values are normal.     Fan motor trouble (Replace the motor.)
Any one of the above measured values is not normal.     Indoor unit controller trouble (Replace the controller .)
(Reference) DC motor connector pin arrangement
  Pin 1: Vm (red)
  Pin 2: Not used
  Pin 3: Gnd (black)
  Pin 4: Vcc (white)
  Pin 5: Vs (yellow)
  Pin 6: PG (blue)
Important:(A) Turn OFF the power before connecting or disconnecting the motor connectors.
(B) When performing voltage measurement at the indoor controller connector for (3) in the table 
below, the DC motor will trip and voltage output will stop approximately 1 minute after operation 
is started. For this reason, to measure the voltage again, turn OFF the unit once using the 
remote controller, and then start the air conditioner again.
(1) Vm-Gnd: Between pin 1 and pin 3
(2) Vcc-Gnd: Between pin 4 and pin 3
(3) Vs-Gnd: Between pin 5 and pin 3Measurement location
DC 15V +/- 10%
Fluctuation between DC 1.8V to 5.7V CS-KE12NB41
DC 130V to 195VCS-KE18NB4UW
DC 280V to 340V Normal value
57 
						

							 
9-4-2.  Outdoor Fan Motor
This outdoor DC fan motor contains an internal control PCB. Therefore, it is not possible to measure the coil 
resistance, and the following procedure should be used to check the motor.
Perform the trouble diagnosis by Test Run mode described on Installation Instructions.
[Trouble symptom 1] The fan does not stop when the outdoor unit stops.    Outdoor unit controller trouble
[Trouble symptom 2]  The fan motor does not rotate when the outdoor unit is operating.
(Diagnostic procedure)
* Disconnect the motor connectors and measure the voltage at the DC motor connectors on the outdoor 
unit controller (3 locations).
(Diagnostic results)
All of the above measured values are normal.     Fan motor trouble (Replace the motor.)
Any one of the above measured values is not normal.     Outdoor unit controller trouble 
(Replace the controller .)
(Reference) DC motor connector pin arrangement
  Pin 1: Vs (white)
  Pin 2: Not used
  Pin 3: Not used
  Pin 4: Gnd (black)
  Pin 5: Vcc (red)
  Pin 6: FG (blue)
  Pin 7: Vsp (yellow)
[Trouble symptom 3] Motor rotates for some time (several seconds), but then quickly stops, when the outdoor 
unit operates.
(There is trouble in the system that provides feedback of motor rotation speed from the 
motor to the outdoor unit controller.)
[Trouble symptom 4] Fan motor rotation speed does not change during outdoor unit operation.
[Trouble symptom 5] Fan motor rotation speed varies excessively during outdoor unit operation.
(Remedy for symptom 3 to 5)
It is not possible to identify whether the trouble is outdoor unit controller trouble or motor trouble. 
Therefore, first replace the outdoor unit controller, then (if necessary) replace the DC motor.
Important:(A) Turn OFF the power before connecting or disconnecting the motor connectors.
(B) When performing voltage measurement at the outdoor controller connector for (3) in the table 
below, the DC motor will trip and voltage output will stop approximately 10 seconds after 
operation is started. For this reason, to measure the voltage again, first turn OFF the outdoor 
unit power, then, measure the voltage in Test Run mode.
(1) Vs-Gnd: Between pin 1 and pin 4
(2) Vcc-Gnd: Between pin 5 and pin 4
(3) Vsp-Gnd: Between pin 7 and pin 4Measurement location
DC 110V or more
DC 14V or more
After fluctuating 4 times between DC 1.0 to 4.3V
(1 sec. ON) and DC 0 V (1 sec. OFF), the DC
motor trips.Normal value
58 
						

							9-5.  Noise Malfunction and Electromagnetic Interference
An inverter A/C operates using pulse signal control and high frequencies. Therefore, it is susceptible to the effects of external 
noise, and is likely to cause electromagnetic interference with nearby wireless devices. 
A noise filter is installed for ordinary use, preventing these problems. However, depending on the installation conditions, these 
effects may still occur. Please pay attention to the points listed below.
(1) Noise malfunction
This refers to the application of high-frequency noise to the signal wires, resulting in abnormal signal pulses and malfunction.
Locations most susceptible to noise
1. Locations near broadcast stations where 
there are strong electromagnetic waves
2. Locations near amateur radio (short wave) 
stations
3. Locations near electronic sewing machines 
and arc-welding machines
Correction
(The fundamental concept is to make the 
system less susceptible to noise.)
- Insulate for noise or
distance from the noise source. -
1. Use shielded wires.
2. Move unit away from the noise source.
Trouble
Either of the following trouble may occur.
1. The unit may stop suddenly during 
operation.
2. Indicator lamps may flicker.
(2) Electromagnetic interference
This refers to noise generated by high-speed switching of the microcomputer and compressor. This noise radiates through 
space and returns to the electric wiring, affecting any wireless devices (televisions, radios, etc.) located nearby.
Locations most susceptible to noise
1. A television or radio is located near the 
A/C and A/C wiring.
2. The antenna cable for a television or 
radio is located close to the A/C and A/C 
wiring.
3. Locations where television and radio 
signals are weak.
Correction
1. Select a separate power source.
2. Keep the A/C and A/C wiring at least 1 meter 
away from wireless devices and antenna cables.
3. Change the wireless device's antenna to a 
high-sensitivity antenna.
4. Change the antenna cable to a BS coaxial cable.
5. Use a noise filter (for the wireless device).
6. Use a signal booster.
Trouble
1. Noise appears in the television picture, 
or the picture is distorted.
2. Static occurs in the radio sound.
59 
						

							Insulation 
tester
Probe
Clip
Ground wire
Terminal plate
Copper
tube or
metallic partClip
Insulation 
testerProbe
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Copper
tube or
metallic partClip
Insulation 
testerProbe
Clip
Insulation 
tester Probe
Metallic 
partFrom fan motor,
compressor and 
other parts
10.  CHECKING ELECTRICAL COMPONENTS
10-1.  Measurement of Insulation 
Resistance
The insulation is in good condition if the resistance 
exceeds 1M ohm.
10-1-1. Power Supply Cord
Clamp the grounding wire of power cord with the lead 
clip of the insulation resistance tester and measure the 
resistance by placing a probe on either of the two 
power wires. (Fig. 1)
Then also measure the resistance between the 
grounding and other power terminals. (Fig. 1)
10-1-2. Indoor Unit
Clamp an aluminum plate fin or copper tube with the 
lead clip of the insulation resistance tester and 
measure the resistance by placing a probe on each 
terminal screw on the terminal plate. (Fig. 2) 
Note that the ground line terminal should be skipped 
for the check.
10-1-3. Outdoor Unit
Clamp a metallic part of the unit with the lead clip of 
the insulation resistance tester and measure the 
resistance by placing a probe on each terminal screw 
where power supply lines are connected on the 
terminal plate. (Fig. 2)
10-1-4. Measurement of Insulation 
Resistance for Electrical Parts
Disconnect the lead wires of the desired electric part 
from terminal plate, capacitor, etc. Similarly disconnect 
the connector. Then measure the insulation resistance. 
(Figs. 3 and 4)
Refer to Electric Wiring Diagram.
If the probe cannot enter the poles because the hole is 
too narrow then use a probe with a thinner pin.
NOTE
60