SERVICE MANUAL CONTENTS

Transcription

1 TopPage SERVICE MANUAL SPLIT TYPE ROOM AIR CONDITIONER MODELS INDOOR UNIT AY-XPGR-N OUTDOOR UNIT AE-XGR-N In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used. CHAPTER. SPECIFICATION [] SPECIFICATION... - [] EXTERNAL DIMENSION... - [] WIRING DIAGRM... - [] ELECTRICAL PARTS... - CHAPTER. EXPLAMATION OF CIRCUIT AND OP- ERATION [] BLOCK DIAGRAMS... - [] MICROCOMPUTER CONTROL SYSTEM... - [] FUNCTION CONTENTS [] MALFUNCTION (PARTS) CHECK METH- OD...-8 [7] OUTDOOR UNIT CHECK METHOD...-0 [8] TROUBLESHOOTING GUIDE...- CHAPTER. REFRIGERATION CYCLE [] FLOW FOW REFRIGERANT...- [] STANDARD CONDITION...- [] TEMPERATURE AT EACH PART AND PRESSURE IN -WAY VALVE...- [] PERFORMANCE CURVES...- CHAPTER. FUNCTION AND OPERATION OF PRO- TECTIVE PROCEDURES [] PROTECTION DEVICE FUNCTIONS AND OPERATIONS... - [] AIR CONDITIONER OPERATION IN THERMISTOR ERROR... - [] THERMISTOR TEMPERATURE CHAR- ACTERISTICS... - [] HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY... - [] GENERAL TROUBLESHOOTING CHART... - CHAPTER. DISASSEMBLING PROCEDURE [] DISASSEMBLY OF INDOOR UNIT...- [] DISASSEMBLY OF OUTDOOR UNIT...-7 Parts Guide Parts marked with " " are important for maintaining the safety of the set. Be sure to replace these parts with specified ones for maintaining the safety and performance of the set. This document has been published to be used for after sales service only. The contents are subject to change without notice.

2 AEXGRN AEXGRN CHAPTER. SPECIFICATION Service Manual [] SPECIFICATION. AY-XPGR-N AE-XGR-N MODEL INDOOR UNIT OUTDOOR UNIT ITEMS AY-XPGR-N AE-XGR-N Cooling capacity(min. Max.) kw. ( ) Heating capacity(min. Max.) kw. (0.9 -.) Moisture removal(at cooling) Liters/h. Electrical data Phase Single Rated frequency Hz 0 Rated voltage V 0 0 Rated current Cool A. ( ) (Min - Max.) Heat A. ( ) Rated input (Min - Max.) Cool W 87 (0 0 ) Heat W 0 ( ) Power factor Cool % 9 87 Heat % Compressor Type Hermetically sealed rotary type Model DAAFF Oil charge 0mL Ester oil VG7 Refrigerant system Evaporator Louver Fin and Grooved tube type Condenser Corrugate Fin and Grooved tube type Control Expansion valve Refrigerant (R0A) 00g De-lce system Micro computer controled reversed systems Noise level (at cooling/heating) High db(a) 0/ 7/9 Low db(a) 8/8 Soft db(a) 7/ Fan system Drive Direct drive Air flow quantity High m/min. 0./.9 /0 (at cooling/heating) Low m/min. 9./0. Soft m/min..9/8.7 Fan Cross flow fan Propeller fan Connections Refrigerant coupling Flare type Refrigerant tube size Gas, Liquid /", /" Drain piping mm O.D φ8 Others Safety device Compressor: Thermal protector Fan motors: Thermal fuse Fuse, Micro computer control Air filters Polypropylene net (Washable) Net dimensions Width mm Height mm 78 0 Depth mm 98 Net weight kg 0 9 NOTE: The condition of star marked item are ISO : 99(E), contition T.

3 INVERTER AIR CONDITIONER [] EXTERNAL DIMENSION AEXGRN. Indoor Outdoor

4 AEXGRN [] WIRING DIAGRM. Indoor. Outdoor [] ELECTRICAL PARTS. Indoor DESCRIPTION MODEL REMARKS Indoor fan motor MLB08 DC Motor Indoor fan motor capacitor Transformer FUSE QFS-GA0JBZZ (0V,.A) FUSE QFS-GA0JBZZ (0V, A). Outdoor Unit DESCRIPTION MODEL REMARKS Compressor DAAFF D.C. brush-less motor Outdoor fan motor ML-A90 DC Motor Outdoor fan motor capacitor Fu QFS-GA0JBZZ(0V, A) Fu QFS-GA0JBZZ(0V, A) Fu QFS-GA0JBZZ(0V,.A) Fu QFS-CA00JBZZ(0V, 0A) Fu, QFS-CA00JBZZ(0V, A)

5 AEXGRN CHAPTER. EXPLAMATION OF CIRCUIT Service AND OPERATION Manual AEXGRN [] BLOCK DIAGRAMS. Indoor DC power supply circuit Fan motor PWM control circuit Rectification circuit A Fuse Indoor fan motor.a Fuse AC power Rotation pulse input circuit Fan motor pulse detect AC clock circuit CPU Remote controller signal reception circuit Buzzer drive circuit CPU reset circuit CPU oscillator circuit Room temp. detect circuit Heat exchanger pipe thermo circuit EEPROM Wireless remote control operation Audible operation confirmation Room temp. thermistor Heat exchanger pipe thermistor Louvre angle, fan speed Select circuit Serial I/O circuit Power supply relay drive circuit Wireless, preheat, Model select Indoor/outdoor control signal I/O Outdoor power supply on/off control Unit- wiring (AC power and serial signals) Auto restart circuit Test run circuit Auxiliary mode Power on circuit Cluster generator drive circuit Test run (forced operation) Auxiliary mode button ON/OFF Self diagnostics, fault diagnosis Cluster generator Serial signals Sub CPU Louvre motor drive circuit(upper) Louvre motor drive circuit(lower) LED drive circuit Flow direction control (louver motor upper) Flow direction control (louver motor lower) LED display

6 AEXGRN. Outdoor AC clock circuit Pulse amplitube modulation circuit Power supply circuit Smoothing circuit IGBT A protection Power factor converter circuit Filter circuit 0A protection Unit- wiring (AC power and serial signals) CPU oscillator circuit DC overvoltage detection circuit Outdoor fan drive circuit Outdoor fan.a protection -way valve relay drive circuit DC overcurrent detection circuit Power transistor module drive circuit -way valve Power transistor module A protection CPU Serial I/O circuit CPU reset circuit Position detection circuit Compressor AC overcurrent detection circuit Compressor thermo circuit Heat exchanger pipe thermo circuit Outdoor temp. thermo. circuit Current transformer Compressor thermistor Heat exchanger pipe thermistor Outdoor temperature thermistor EEPROM LED drive circuit Test mode circuit LED Expansion valve drive circuit Suction temp. thermo. circuit -way valve temp. thermo. circuit Expansion valve Suction pipe thermistor -way valve thermistor

7 [] MICROCOMPUTER CONTROL SYSTEM AEXGRN. Indoor.. Electronic control circuit diagram 0 DISPLAY PWB LOUVER MOTOR BOTTOM JPF V.7K RN R.K 0.0KF R9 TEMP THERMO PIPE THERMO FLASH JPT HOT KEEP AUTO RESTART POWER ON R 0K (HA CIRCUIT) PREHEAT WIRELESS C 0V 0.μ V AUX. (TEST RUN) TEST SW CONNECTOR OF JOINT BCN (FAN MOTOR) DC FAN MOTOR GND for V LINE GND for V LINE SERIAL SIGNALS REMOTE CONTROLLER SIGNAL ERROR SIGNAL OF SERIAL POWER SUPPLY OF SUB MICRO COMPUTER R k FU.A - 0V BCN CNA V N IN RG RC RB RA R0 V W W W W D8 DN0 DN0 D7 R7 R9.7k PC PC87XP C0 0V0.0μ R8 00k C8 V00μ ZDHZ- R70.7K RD PC PC8HXP (SERIAL I/O CIRCUIT) 7-SEGLED& RECEIVER PWB CONNECTOR OF JOINT (DRAIN PAN) SUB MICRO COMPUTER PWB W 80 0 LOUVER MOTOR TOP C V 0.μ DRAIN PAN ASS'Y CIRCUIT DIAGRAM V R /W.8k C V7μ C V D 70μ DSM AC CLOCK Q KRC08S V Q KRA0S R97.7k R7.7k V JPH JPO R 0K R90 JPS MQ R7 0K R8 0k R.8k PC R0 PC 80 PC87XP R7 k R k C V.7μ C7 0V 000p R8 0K R 8.k R.8k Vm GND PG Vcc Vs C 0V 0.0μ Q KRC0S V 7 7 PC V PC87P SSR R7 00 W C 7V 0.0μ RE W K V V RH BCN W K W K C~C 0V700p D DN0 R 00K /W R 00K /W C 7V 0.μ NF R9 /W 70K R 0K C 7V 0.μ NR BUSY VPP VCC SCL SDA OE RESET VSS ZD ST0D - 00 CN80 V R. W DB DSBA0 DCV V V HAJP C C C C R 9K E C90 CN90 R9 00k R9 C 0V 00μ V R9.7K R8.7K R9 00K C V 0.μ RF R M /W /W M FU A - 0V C 0V 0μ PC87XP R9 C 0V 000p R k 00K R7.K R 0.μ 0V C7 C0 V 0.μ C V 00μ 0V V V V JPP JPW 0k R0 7k R7 R /W 00 R /W 00 R 0K CN R8 0K R9 0K C V 0.0μ R0 0.0KF C9 V 0.0μ V0μ C R 0.0KF V0μ C0 V TH TH TR C 0V 0.μ V IC9 PJCT 0μH L C 0V 0μ D DFS C7 0V 70μ V EEPROM IC0 C V 0.μ R8 0K R87 0K RESET IC C7 0.μ V P7 P P P P P P P0 VCC VR VSS P7 P P P P C7 V 0.0μ R9.k R 0k V 0 98 P P P0 P7 P P P P P P P0 P7 P P P P IC P00 8 P0 7 P0 P0 P0 P0 P0 P07 P0 0 P 9 P 8 P 7 P P P P P0 P P P P P P P7 VSS XOU XIN P0 P RST VSS P C V 0.0μ R.7K C 0V 000p C 0V 00μ V Q9 KRC0S OSC 8MHz C7 V 0.0μ R8 0k R9 0K V R.7k KRC08S Q S RY CONNECTOR OF JOINT OUT (CLUSTER) CLUSTER GENERATOR N N C9 0V0.07μ C98 C99 W K R9A /W 70K BZ IC R0.K C8 0V 0000p ZD V D DFL0U R7 KF R R KF 0KF C 00V 00pF C 0V 0V C 00p 00μ IC MR7 C KV p PC9 PC87XP R7 80 C98, C99 KV 000p R.7K /W R0 90 V KID00AF RM.7K.K R7.KF R8 R80.K.KF R PC R9 K R 00K R 00K R8 K PC PC87XP PC7 C9 0V C0 000p R 0KF D DFL0U R DFL0U D D0 DFL0U L D SR9 Q9 KRA0S V KIA78API IC7 PC87XP R7 K R89 K /W R 90 PC87XP R98.7K

8 AEXGRN.. Display circuit diagram CN0 C0 V 7μ 0 V V W80 * 7 R0 LOUVER MOTOR BOTTOM KID78AF R0 LOUVER MOTOR TOP CN0 R0 CN0 R0 GND for V LINE IC0 R0 R0 V LINE GND for R07 MV IC0 OSC0 C0 V 0.μ V R08.7K C0 V.7μ C0 0.μ V SERIAL SIGNALS 8MHz REMOTE CONTROLLER SIGNALS ERROR SIGNAL OF SERIAL MV 0 98 POWER SUPPLY OF SUB MICRO COMPUTER 7 8 P P P P0 P P P P P P P7 Vref RESET CNVss Vcc Xin Xout Vss CIRCUIT DAIGRAM IC0 M7 KID00AF V IC0 MV P P0 P07 P0 P0 P0 P0 0 P0 9 P0 8 P00 7 P7 P P P P P P 0 P0 9 MV KID00AF V IC0 IC0 7 FLASH.7K R Q0 Q0 KRA0S KRA0S Q0 Q0 KRC0S KRC0S R8 0K R 00K R09 R R0 R c d e g GND for V LINE /W.K* JP GND for V LINE RESET C0 0V 0.μ JP SUB MICRO COMPUTER PWB GND for V LINE GND for V LINE GND for V LINE GND for V LINE V Q0 KRC0S R9 K f f KID00AF V V 7 8 LED B PC LED LED LED LED LED LED LED LED LED LED CN0B ( ) B LU E CN0A CN0C DISPLAY PWB 7 - SEG LED & RECEIVER PWB SG0 (COM) 0 (COM) A A B C H G D B F C E H G D F E (H) 9 (G) 8 (F) (E) (D) (C) (B) 7 (A) (H) 9 (G) 8 (F) (E) (D) (C) (B) 7 (A) g f e d c b a g f e d c b a a b c d e g V 0 SIGNALS REMOTE CONTROLLER R0 7 GND for V LINE 0 CN0B CN0A C0 V 7μ + C0 V IC0 GPURK RECEIVER CIRCUIT 0.μ

9 .. Printed wiring board AEXGRN

10 AEXGRN. Outdoor.. Electronic control circuit diagram

11 .. Printed wiring board AEXGRN 7

12 AEXGRN [] FUNCTION. Function.. Startup control The main relay remains off during the first seconds (first safety time) immediately after the power cord is plugged into an AC outlet in order to disable outdoor operation and protect outdoor electric components... Restart control Once the compressor stops operating, it will not restart for 80 seconds to protect the compressor. Therefore, if the operating compressor is shut down from the remote control and then turned back on immediately after, the compressor will restart after a preset delay time. (The indoor will restart operation immediately after the ON switch is operated on the remote control.) Compressor operation Compressor ON OFF operation on remote control Compressor remains OFF for 80 seconds ON operation on remote control.. Cold air prevention control When the air conditioner starts up in heating mode, the indoor fan will not operate until the temperature of the indoor heat exchanger reaches about C in order to prevent cold air from blowing into the room. Also, the indoor fan operates at low speed until the temperature of the indoor heat exchanger reaches about 8 C so that people in the room will not feel chilly air flow. Indoor heat exchanger temperature 8.. Odor prevention control Set fan speed Compressor can turn ON Compressor ON Indoor fan at low speed Indoor fan in non-operation When the air conditioner starts up in cooling mode, the discharged air temperature is lowered slightly, and for the reduction of unpleasant odors the operation of the indoor fan is delayed 0 seconds if the automatic fan speed mode in cooling mode is set... Indoor heat exchanger freeze prevention control If the temperature of the indoor heat exchanger remains below 0 C for consecutive minutes during cooling or dehumidifying operation, the compressor operation stops temporarily in order to prevent freezing. When the temperature of the indoor heat exchanger rises to C or higher after about 80 seconds, the compressor restarts and resumes normal operation... Outdoor -way valve freeze prevention control If the temperature of the outdoor -way valve remains below 0 C for 0 consecutive minutes during cooling or dehumidifying operation, the compressor operation stops temporarily in order to prevent freezing. When the temperature of the -way valve rises to 0 C or higher after about 80 seconds, the compressor restarts and resumes normal operation..7. Indoor overheat prevention control During heating operation, if the temperature of the indoor heat exchanger exceeds the indoor heat exchanger overheat prevention temperature (about to C) which is determined by the operating frequency and operating status, the operating frequency is decreased by about to Hz. Then, this operation is repeated every 0 seconds until the temperature of the indoor heat exchanger drops below the overheat protection temperature. Once the temperature of the indoor heat exchanger drops below the overheat protection temperature, the operating frequency is increased by about to 0 Hz every 0 seconds until the normal operation condition resumes. If the temperature of the indoor heat exchanger exceeds the overheat protection temperature for 0 seconds at minimum operating frequency, the compressor stops operating and then restarts after about 80 seconds, and the abovementioned control is repeated..8. Outdoor overheat prevention control During cooling operation, if the temperature of the outdoor heat exchanger exceeds the outdoor heat exchanger overheat prevention temperature (about C), the operating frequency is decreased by about to Hz. Then, this operation is repeated every 0 seconds until the temperature of the outdoor heat exchanger drops to about C or lower. Once the temperature of the outdoor heat exchanger drops to about C or lower, the operating frequency is increased by about to 0 Hz every 0 seconds until the normal operation condition resumes. If the temperature of the outdoor heat exchanger exceeds the outdoor heat exchanger overheat protection temperature for (0 sec : outdoor temperature 0 C 0 sec : outdoor temperature < 0 C) at minimum operating frequency, the compressor stops operating and then restarts after about 80 seconds, and the abovementioned control is repeated..9. Compressor overheat prevention control If the temperature of the compressor exceeds the compressor overheat prevention temperature (0 C), the operation frequency is decreased by about to 0 Hz. Then, this operation is repeated every 0 seconds until the temperature of the compressor drops below the overheat protection temperature (00 C). Once the temperature of the compressor drops below the overheat protection temperature, the operating frequency is increased by about to 0 Hz every 0 seconds until the normal operation condition resumes. If the temperature of the compressor exceeds the overheat protection temperature (for 0 seconds in cooling operation or 0 seconds in heating operation) at minimum operating frequency, the compressor stops operating and then restarts after about 80 seconds, and the abovementioned control is repeated. 8

13 .0. Startup control When the air conditioner starts in the cooling or heating mode, if the room temperature is C higher than the set temperature (in cooling operation) or. C lower (in heating operation), the air conditioner operates with the operating frequency at maximum. Then, when the set temperature is reached, the air conditioner operates at the operating frequency determined by fuzzy logic calculation, then enters the normal control mode after a while... Peak control If the current flowing in the air conditioner exceeds the peak control current (see the table below), the operation frequency is decreased until the current value drops below the peak control current regardless of the frequency control demand issued from the indoor based on the room temperature. Model Peak control current Cooling operation Heating operation AY-XPGR-N Approx.. A Approx.8.7 A.. Outdoor fan delay control The compressor stops immediately after cooling, dehumidifying or heating operation is shut down, but the outdoor fan continues operation for 0 seconds before it stops... Defrosting.. Reverse defrosting The defrost operation starts when the compressor operating time exceeds 0 minutes during heating operation, as shown below, and the outside air temperature and the outdoor heat exchanger temperature meet certain conditions. When the defrost operation starts, the indoor fan stops. The defrost operation stops when the outdoor heat exchanger temperature rises to about C or higher or the defrosting time exceeds 0 minutes. 0 min or more 0 min or more 0 min or more Start of heating operation.. ON timer The ON timer can be activated by pressing the ON timer button. When the ON timer is activated, the operation start time is adjusted based on fuzzy logic calculations hour before the set time so that the room temperature reaches the set temperature at the set time... OFF timer The OFF timer can be activated by pressing the OFF timer button. When the OFF timer is set, the operation stops after the set time. When this timer is set, the compressor operating frequency lowers for quieter operation, and the room temperature is gradually varied after one hour (reduced C three times (max. C) in heating, or increased 0. C three times (max. C) in cooling or dehumidifying operation) so that the room temperature remains suitable for comfortable sleeping. Heating operation Set temperature Activation of OFF timer Activation of OFF timer Defrosting Max. 0 min hour later hour later - O C O - C Max.. hours later Cooling/dehumidifying operation C C 0.O 0. O C 0.O Set temperature Max.. hours later Defrosting Max. 0 min - O C Max. hours later Max. hours later Timer setting reached Timer setting reached AEXGRN.. Power ON start If a jumper cable is inserted in the location marked with HAJP on the indoor control printed circuit board (control PCB), connecting the power cord to an AC outlet starts the air conditioner in either cooling or heating mode, which is determined automatically by the room temperature sensor. When a circuit breaker is used to control the ON/OFF operation, please insert a jumper as described above..7. Self-diagnostic malfunction code display.7. Indoor ) When a malfunction is confirmed, all relays turn off and a flashing malfunction code number is displayed to indicate the type of malfunction. When the air conditioner is in non-operating condition, holding down AUX button for more than seconds activates the malfunction code display function. The operation continues only in the case of a serial open-circuit, and the main relay turns off after 0 seconds if the open-circuit condition remains. In the case of a serial short-circuit, the air conditioner continues operating without a malfunction code display, and the main relay turns off after 0 seconds if the short-circuit condition remains. The malfunction information is stored in memory, and can be recalled later and shown on display. ) The self-diagnostic memory can be recalled and shown on the display by stopping the operation and holding down AUX button for more than seconds. ) The content of self-diagnosis (malfunction mode) is indicated by a flashing number. (For details, refer to the troubleshooting section.).7. Outdoor If a malfunction occurs, LED on the outdoor flashes in 0.-second intervals as shown below. (Example) Compressor high temperature abnormality ON OFF sec sec 0. sec.8. Information about auto mode In the AUTO mode, the temperature setting and mode are automatically selected according to the room temperature and outdoor temperature when the is turned on. Modes and Temperature Settings the figures in ( ) are temperature settings During operation, if the outdoor temperature changes, the temperature settings will automatically slide as shown in the chart. 9

14 AEXGRN.9. Airflow control The airflow control holds the two upper and lower louvers at special positions during operation to prevent discharged air from directly blowing onto people in the room..9. Cooling/dehumidifying operation When the airflow button is pressed the upper louver is set at an upward angle to send the air along the ceiling..9. Heating When the airflow button is pressed the lower louver is set at a downward angle to send the air directly toward the floor..0. Difference of operation in Auto and Manual modes In the Auto mode, the temperature setting is automatically determined based on the outside air temperature. In addition, the air conditioner operation differs from the operation in the Manual mode as explained below..0. Difference relating to set temperature Auto mode Manual mode Temperature setting method Cooling Automatic temperature setting based on Heating outside air temperature. Can be changed within ± C using remote control. Dehumidifying Cooling Heating Dehumidifying Can be changed between 8 and C using remote control. Can be changed between 8 and C using remote control. Automatic setting. Can be changed within ± C... Dehumidifying operation control If the room temperature is C or higher when dehumidifying operation starts, the dehumidifying operation provides a low cooling effect in accordance with the room temperature setting automatically determined based on the outside air operation. (The setting value is the same as the set temperature for cooling operation in the auto mode.) If the room temperature is lower than C when dehumidifying operation starts, the dehumidifying operation minimizes the lowering of the room temperature... Self Clean operation Heating or Fan operation and Cluster operation are performed simultaneously. The judgment of whether Heating or Fan operation is used is based on the outside air temperature at minutes after the start of internal cleaning. The operation stops after 0 minutes. (The air conditioner shows the remaining minutes: ) Heating operation Fan operation O C Outside air temperature.. Plasmacluster Ion function Operating the Plasmacluster Ion button while the air conditioner is in operation or in non-operation allows the switching of the operation mode in the following sequence: Air Clean operation Stop. Self Clean operation generates about equal amounts of (+)ions and (-)ions from the cluster to provide clean air. If the Plasmacluster Ion generation function is operated together with the air conditioner operation, the indoor fan speed and louver direction are in accordance with the air conditioner settings. If the Plasmacluster Ion generation function is used without operating the air conditioning function, the indoor fan operates at a very low speed and the upper louver is angled upward and the lower louver remains horizontal. (The airflow volume and direction can be changed by using the remote control.).. Hot keep When the room temperature rises above the set temperature by 0. C or more, the ON/OFF operation of the compressor and indoor fan is controlled in order to lower the room temperature. (The values indicated below, such as "0. C" and ". C," vary depending on the outside air temperature.). O C 0. O C Set temperature.. Hot keep zone With the compressor frequency at the lowest, if the room temperature is higher than the set temperature by 0. C but no more than. C, the following processes will be activated. ) The compressor stops temporarily, and restarts after minutes. ) If the room temperature remains in the hot keep zone, the compressor is turned OFF and ON in -minute intervals. ) The indoor fan turns OFF and ON with a delay of 0 seconds from the compressor OFF/ON. ) After the above operation in -minute intervals is repeated four times, the interval extends to minutes... Hot keep zone If the compressor ON/OFF in hot keep zone fails to bring the room temperature within. C above the set temperature, the following processes will be activated. ) The compressor repeats a cycle of 8-minute OFF and -minute ON. ) After the second time, the compressor remains completely OFF and only the indoor fan repeats OFF-ON in set intervals. ) While the compressor is completely OFF in ), the louvers are set horizontally to prevent cold air from blowing. The zone transition and the end of hot keep operation (room temperature lower than the set temperature) are judged when the compressor ON period ends. * This function cannot be repealed... Winter cool Cooling operation is available during the winter season by the built in winter cool function. Lower limit of outdoor temperature range is -0 C DB. When the outside air temperature is low, the outdoor fan operates at slower speed. NOTE: Built-in protect device may work when outdoor temperature falls below C DB., depending on conditions. 0

15 .. Auto restart When power failure occures, after power is recovered, the will automatically restart in the same setting which were active before the power failure... Operating mode (Cool, Heat, Dry) Temperature adjustment (within C range) automatic operation Temperature setting Fan setting Air flow direction Power ON/OFF Automatic operation mode setting Swing louvre Plasmacluster mode.. Setting not memorized Timer setting Full power setting Internal cleaning AEXGRN.. Disabling auto restart function By removing (cutting) jumper J (JPJ) on the printed circuit board (PCB), the auto restart function can be disabled.. Explanation of cluster circuit The cluster generates cluster ions, which are circulated throughout the room by the air flow created by the blower fan (indoor fan motor) in the air conditioner. ) When microcomputer output turns "H," the IC output changes to "Lo," turning ON the SSR and applying 0 V to the cluster for the generation of cluster ions (positive and negative ions). AC0V Microcomputer output IC R7 R R0 V SSR R7 C RE RH Cluster. Outline of PAM circuit.. PAM (Pulse Amplitude Modulation) The PAM circuit varies the compressor drive voltage and controls the rotation speed of the compressor. The IGBT shown in the block diagram charges the energy (electromotive force) generated by the reactor to the electrolytic capacitor for the inverter by turning ON and OFF. Reactor L DB AC 0V Noise filter Reactor L + IPM Compressor AC clock detection circuit DB IGBT IGBT drive circuit Overvoltage detection circuit Compressor position detector [PAM drive circuit] Microcomputer (IC) PAM drive circuit block diagram

16 AEXGRN When the IGBT is ON, an electric current flows to the IGBT via the reactor (L), (L) and diode bridge (DB). When the IGBT turns OFF, the energy stored while the IGBT was ON is charged to the voltage doubler capacitor via the diode bridge (DB). As such, by varying the ON/OFF duty of the IGBT, the output voltage is varied. DB Stored energy IGBT ON L Reactor L DB IGBT OFF IGBT.. High power factor control circuit This circuit brings the operating current waveform closer to the waveform of commercial power supply voltage to maintain a high power factor. Because of the capacitor input, when the PAM circuit is OFF, the phase of the current waveform deviates from the voltage waveform as shown below. To prevent this deviation, a current is supplied during the periods indicated by "O" in the diagram. To determine the length of period to supply a current, the zero-cross timing of the AC input voltage is input to the microcomputer via the clock circuit. The power source frequency is also determined at the same time. The IGBT turns ON after the time length determined by the zero-cross point to supply a current to the IGBT via the reactor. This brings the current waveform closer to the voltage waveform in phase. As described above, the ON/OFF operation of the IGBT controls the increase/decrease of the compressor power supply voltage (DC voltage) to improve the compressor efficiency and maintain a high power factor by keeping the current phase closer to that of the supply voltage. AC voltage waveform AC voltage waveform AC current waveform AC current waveform Zero-cross detection AC voltage and current waveforms when PAM is OFF IGBT ON period AC voltage and current waveform when PAM is ON.. Detailed explanation of PAM drive circuit sequence AC voltage waveform Clock IGBT ON A B C 0Hz A B.mS.mS C 0..mS.. AC clock (zero-cross) judgment The clock circuit determines the time from one rising point of the clock waveform to the next rising point. The detected clock waveform is used to judge the power source frequency (0Hz). The zero-cross of the AC voltage is judged as the rising of the clock waveform, as shown in the diagram above... IGBT ON start time (delay time B) Based on the zero-cross of the AC voltage, the IGBT turns ON after a delay time set according to the power source frequency... IGBT ON time (C) After the above delay time, the IGBT turns ON to supply a current to the reactor. The ON time of the IGBT determines the amount of energy (level of DC voltage rise) supplied to the reactor. DC voltage level in each operation mode (varies depending on external load conditions) Cooling operation to 0 V Heating operation to 80 V

17 AEXGRN.. PAM protection circuit To prevent excessive voltage of PAM output from damaging the IPM and electrolytic capacitor as well as the control printed circuit board (PCB), this circuit monitors the PAM output voltage and turns off the PAM control signal and PAM drive immediately when an abnormal voltage output is generated. At the same time, it shuts off the compressor operation. The PAM output voltage is distributed to pin () of the comparator (IC8). If this voltage exceeds the reference voltage at pin () of the IC8, the output of the comparator (IC8) reverses (from H to L) and it is input to pin (8) of the microcomputer (IC) to halt the PAM drive. 0V 70uF C9 C0 R K R 00K R7.7K R8.7K 0V V R K 0V R 9.KF R M IC8 (Overvoltage detection) V R.8K R K IC 0V During abnormal voltage output 8 The protection voltage level is as follows... Details of troubleshooting procedure for PAM ) PAM shutdown due to ) When the DC voltage detection circuit sends a signal exceeding the specified voltage to the microcomputer DC voltage of 0 V or higher (detection circuit input voltage of about 9. V or higher) [IC8 pin ()] When an is detected PAM IGBT turns OFF. Compressor turns OFF. All s shut down completely when the occurs four times. ) When the outdoor clock waveform differs from the specified value immediately before the PAM IGBT turns ON When there is no clock waveform input When a clock signal of other than specified power source frequency (0/0 Hz) is input When an is detected PAM IGBT does not turn ON. Compressor operates normally. Complete shutdown does not occur. ) PAM indication In case of ) An signal is sent to the indoor as soon as an is generated. Malfunction No. -0 is indicated when the code is called out by the indoor 's self-diagnosis function. The LED on the outdoor flashes times when an is generated. The LED continues flashing in the -time cycle even after the compressor stops operating. The LED turns off (data is deleted from the memory) when the outdoor power is turned off. In case of ) An signal is sent to the indoor as soon as an is judged. Malfunction No. - is indicated when the code is called out by the indoor 's self-diagnosis function. The LED on the outdoor flashes times when an is judged. The LED on the outdoor flashes in normal pattern when the compressor stops operating. (Compressor OFF or Thermostat OFF from remote control) * When a user complains that the air conditioner does not provide sufficient cool air or warm air In addition to conventional -generating reasons, there is a possibility that the PAM IGBT does not turn ON even if the compressor is operating. In that case, the DC voltage does not rise even though the compressor is operating, and lowers to the 80-VDC level. Check items Clock circuit check PAM IGBT check Fuse (Fu) open-circuit check

18 AEXGRN. Explanation of IPM drive circuit The IPM for compressor drive is made by Mitsubishi Electric. The power supply for the IPM drive, the shunt resistance for overcurrent detection, etc., are provided outside the IPM (control PCB)... IPM drive power supply circuit The power supply for the upper-phase IGBT (HU, HV, HW) drive employs a bootstrap system, and provides power to the upper-phase IC. The -V power supply for the lower-phase IC is provided by the control printed circuit board (PCB)... Brief explanation of bootstrap system (single power drive system) To supply power to the upper-phase IC, the microcomputer (IC) turns ON the lower-phase IGBT (LU, LV, LW). This results in a charging current that flows to the electrolytic capacitor of each upper-phase IC input and charges the bootstrap capacitor with a -V current. The power supply for the subsequent stages is charged while the lower-phase IGBT is ON in ordinary compressor drive control. Initial charge period Charging current group P(Vcc) Bootstrap capacitor VDB (HU,HV,HW) HVIC High-voltage-withstanding, high-speed recovery diode U,V,W, VD (LU,LV,LW) LVIC N-side IGBT VCIN(n) N(GND Bootstrap circuit

19 .. DC overcurrent detection circuit AEXGRN When a current of about A or higher flows through the shunt resistance (R9) on the control printed circuit board (PCB), the voltage at this resistance is input to IPM CIN pin (). Then, the gate voltage of the lower-phase IGBT (LU, LV, LW) inside the IPM turns OFF to cut off the overcurrent. At the same time, an L output of about.8 ms is generated from IPM Fo pin (), and this results in an L input to overcurrent detection input pin () of the microcomputer (IC) and turns OFF the PWM signal output (IC pins () through ()) to the IGBT gate. Protection circuit status SET RESET (Lower phase) Internal IGBT gate (About A) SC a Output current Ic (A) SC reference voltage Sense voltage relative to shunt resistance Delay by CR time constant circuit Error output Fo About.8 ms P Shunt resistance Overcurrent R9 N V IC IPM overcurrent detection circuit CiN FO 0V

20 AEXGRN. 0 energizing control (digital position detection control) This control system detects the digital position detection signal and adjusts the rate of acceleration/deceleration accordingly. The motor's induced voltage waveform is input to the comparator in the form of PWM-switched pulse waveform, and a position detection signal is generated as a reference voltage equaling / of 80 VDC. However, since there is no induced voltage waveform when the PWM waveform is OFF, the microcomputer performs internal processing so that detection is enabled only when it is ON. Based on the detected position signal, actual PWM waveform output timing is determined. Since it does not use a filter circuit, the detection accuracy is high. The microcomputer performs internal processing to cancel spike voltage during the regenerative process. Furthermore, even if the induced voltage is low, position detection is still possible, thus allowing sensor-less operation at low rotation speed in the initial stage of operation. This reduces the starting current and improves the IPM reliability. Terminal voltage waveform Reference voltage (/ of DC voltage) Spike voltage (cancelled) Comparator output waveform (Position signal waveform)

21 AEXGRN AEXGRN CHAPTER. FUNCTION AND OPERATION Service OF PROTECTIVE Manual PROCEDURES [] PROTECTION DEVICE FUNCTIONS AND OPERATIONS Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor display Indoor Outdoor Indoor fan lock Operation stops if there is no input of rotation pulse signal from indoor fan motor for minute. Indoor fan rotation speed Indoor freeze prevention -way valve freeze prevention Indoor heat exchanger overheat shutdown Outdoor heat exchanger overheat shutdown Compressor discharge overheat shutdown 7 Dehumidifying operation temporary stop 8 DC overcurrent Operation stops if rotation pulse signal from indoor fan indicates abnormally low speed (about 00 rpm or slower). Compressor stops if temperature remains below 0 C for minutes. Compressor stops if temperature of outdoor -way valve remains below 0 C for 0 continuous minutes during cooling or dehumidifying operation. Operating frequency lowers if indoor heat exchanger temperature exceeds overheat temperature during heating operation. Compressor stops if indoor heat exchanger temperature exceeds overheat temperature for 0 seconds at minimum frequency. Overheat temperature setting value indoor heat exchanger thermistor temperature: about to C Operation frequency lowers if outdoor heat exchanger temperature exceeds about C during cooling operation. Compressor stops if outdoor heat exchanger temperature exceeds about C for 0 seconds at minimum frequency. Operating frequency lowers if temperature of compressor chamber thermistor (TH) falls below about 0 C. Compressor stops if temperature of compressor chamber thermistor (TH) remains at about 0 C (for 0 seconds in cooling operation, or 0 seconds in heating operation) at minimum frequency. Compressor stops if outside air temperature thermistor is lower than about C during dehumidifying operation. Compressor stops if electric current of about A or higher flows in IPM. When indoor fan is in operation When indoor fan is in operation When in cooling or dehumidifying operation When in cooling or dehumidifying operation When in heating operation When in cooling or dehumidifying operation When compressor is in operation When in dehumidifying operation When compressor is in operation Operation OFF or ON Yes None Operation OFF or ON Yes None Automatic reset when heat exchanger temperature rises above freeze prevention temperature ( C or higher) Automatic reset when temperature of -way valve rises above 0 C. Automatic reset after safety period (80 sec). Automatic reset after safety period (80 sec). Automatic reset after safety period (80 sec). None None None Yes Yes None Yes Yes None Yes Yes None Yes Yes Automatic reset when outside air temperature rises above C. None Yes Yes Operation OFF or ON Yes Yes Yes

22 AEXGRN Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor Indoor Outdoor 9 AC overcurrent 0 AC overcurrent in compressor OFF status AC maximum current AC current deficiency Thermistor installation or -way valve Compressor high temperature Outdoor heat exchanger thermistor short-circuit Outdoor outside air temperature thermistor short-circuit 7 Outdoor suction thermistor short-circuit 8 Outdoor -way valve thermistor short-circuit 9 Outdoor heat exchanger thermistor open-circuit 0 Outdoor outside air temperature thermistor open-circuit Outdoor suction thermistor open-circuit Outdoor -way valve thermistor open-circuit Outdoor discharge thermistor open-circuit Operating frequency lowers if compressor AC current exceeds peak control current value. Compressor stops if compressor AC current exceeds peak control current value at minimum frequency. Indoor and outdoor s stop if AC current exceeds about A while compressor is in non-operation status. Compressor stops if compressor AC current exceeds 7 A. Compressor stops if operating frequency is 0 Hz or higher and compressor AC current is about.0 A or lower. Compressor stops if high and low values of temperatures detected by outdoor heat exchanger thermistor (TH) and -way valve thermistor (TH) do not match operating cycle. Compressor stops if compressor chamber thermistor (TH) exceeds about C, or if there is short-circuit in TH. Compressor stops if there is short-circuit in outdoor heat exchanger thermistor (TH). Compressor stops if there is short-circuit in outdoor outside air temperature thermistor (TH). Compressor stops if there is short-circuit in outdoor suction thermistor (TH). Compressor stops if there is short-circuit in outdoor -way valve thermistor (TH). Compressor stops if there is open-circuit in outdoor heat exchanger thermistor (TH). Compressor stops if there is open-circuit in outdoor outside air temperature thermistor (TH). Compressor stops if there is open-circuit in outdoor suction thermistor (TH). Compressor stops if there is open-circuit in outdoor -way valve thermistor (TH). Compressor stops if there is open-circuit in outdoor discharge thermistor (TH). Serial signal Power relay turns OFF if indoor cannot receive serial signal from outdoor for 8 minutes. Compressor stops if outdoor cannot receive serial signal from indoor for 0 seconds. When compressor is in operation When compressor is in non-operation When compressor is in operation When compressor is in operation minutes after compressor startup display Operation OFF or ON Yes Yes Yes Replacement of defective parts such as IPM Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes When in operation Operation OFF or ON Yes Yes Yes At compressor startup At compressor startup At compressor startup At compressor startup At compressor startup At compressor startup At compressor startup At compressor startup At compressor startup When in operation When in operation Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON Yes Yes Yes Operation OFF or ON (Automatic reset when less than 8 minutes) Reset after reception of serial signal Yes None None None None

23 Compressor startup Compressor stops if compressor fails to start up. Compressor rotation Compressor stops if there is no (at 0 input of position detection signal energizing) from compressor or input is abnormal. 7 Outdoor DC fan Operation stops if there is no input of rotation pulse signal from outdoor fan motor for 0 seconds. 8 PAM overvoltage Compressor stops if DC voltage is 0 V or higher. 9 PAM clock When power source frequency cannot be determined (at startup), or when power source clock cannot be detected for continuous second (at startup). 0 IPM pin level When Outdoor starts to run, MCU checks control pin levels of IPM. If MCU detects some pin levels isn t different from another pin level. MCU doesn t run Compressor. The outdoor restarts four times before the indoor is displayed (complete shutdown). A single judgment results in the display of the indoor (complete shutdown). The outdoor restarts eight times before the indoor is displayed (complete shutdown). [] AIR CONDITIONER OPERATION IN THERMISTOR ERROR. Indoor AEXGRN Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor Indoor Outdoor display At compressor startup Operation OFF or ON Yes Yes Yes Compressor operating Operation OFF or ON Yes Yes Yes at 0 energizing When outdoor fan is in operation Operation OFF or ON Yes Yes Yes When in operation Operation OFF or ON Yes Yes Yes At compressor startup, when in operation At compressor startup Compressor continues operation without stopping. None Yes Yes Operation OFF or ON Yes Yes Yes Item Mode Control operation Room temperature thermistor (TH) Heat exchanger thermistor (TH) Auto Operation mode judgment When resistance is low (temperature judged higher than actual) Cooling mode is activated even if room temperature is low. Cooling Frequency control Room becomes too cold. Dehumidifying Room temperature memory Frequency control Normal operation. Heating Frequency control Room does not become warm. Cooling Dehumidifying Heating Freeze prevention Cold air prevention Indoor evaporator may freeze. Cold air prevention deactivates too soon and cold air discharges. Short-circuit Cooling mode is activated in most cases. Air conditioner operates in full power even when set temperature is reached. Room temperature is stored in memory as.0 C, and compressor does not stop. Hot keep status results immediately after operation starts. Frequency does not increase above 0 Hz (0 Hz). Indoor evaporator may freeze. Compressor operates at low speed or stops, and frequency does not increase. When resistance is high (temperature judged lower than actual) Heating mode is activated even if room temperature is high. Room does not become cool. Normal operation. Room becomes too warm. Compressor stops occasionally. Cold air prevention deactivates too slow. Open-circuit Heating mode is always activated. Compressor does not operate. Room temperature is stored in memory as 8. C, and compressor does not operate. Air conditioner operates in full power even when set temperature is reached. Compressor does not operate. Cold air prevention does not deactivate, and indoor fan does not rotate.

24 AEXGRN. Outdoor Item Mode Control operation Compressor chamber thermistor (TH) Heat exchanger thermistor (TH) Outside air temperature thermistor (TH) Suction pipe thermistor (TH) -way valve thermistor (TH) Cooling Dehumidifying Heating Cooling Dehumidifying Heating Auto Cooling Dehumidifying Heating Cooling Dehumidifying Heating Cooling Dehumidifying Heating Expansion valve control and compressor protection Outdoor heat exchanger overheat prevention Expansion valve control Defrosting Operation mode judgment Operation not affected Rating control Defrosting Expansion valve control Expansion valve control Expansion valve control Operation not affected When resistance is low (temperature judged higher than actual) Compressor operates, but room does not become cool or warm (expansion valve is open). Compressor operates at low speed or stops. Defrosting operation is not activated as needed, and frost accumulates on outdoor (expansion valve is closed). Cooling mode is activated even if room temperature is low. Normal operation. Defrosting operation is activated unnecessarily. Compressor operates, but room does not become cool (expansion valve is open). Compressor operates, but room does not become warm (expansion valve is open). Frost accumulates on indoor evaporator and room does not become cool (expansion valve is closed). Normal operation. Short-circuit Compressor high temperature indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. Outdoor thermistor short-circuit indication. When resistance is high (temperature judged lower than actual) Layer short-circuit or open-circuit may result in compressor in normal operation. Normal operation. Defrosting operation is activated unnecessarily, and room does not become warm (expansion valve is open). Heating mode is activated even if room temperature is high. Normal operation. Defrosting operation is not activated, and frost accumulates on outdoor. Frost accumulates on evaporator inlet section, and room does not become cool (expansion valve is closed). Frost accumulates on expansion valve outlet section, and room does not become warm (expansion valve is closed). Compressor operates, but room does not become cool (expansion valve is open). Normal operation. Open-circuit Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication. Outdoor thermistor open-circuit indication.

25 [] THERMISTOR TEMPERATURE CHARACTERISTICS AEXGRN. Indoor thermistor temperature characteristics K TH TH CN CN Resistance (K ) Tester - + Tester 0 0 Heat exchanger thermistor TH (orange) Resistance at : k Room temperature thermistor TH (yellow) Resistance at : 0 k Thermistor Room temperature Symbol TH (CN) Color Yellow Before measuring resistance, disconnect connectors as shown above Heat exchanger TH (CN) Orange Temperature( ) TH Room temperature thermistor TH Heat exchanger thermistor. Outdoor thermistor temperature characteristics Connector CN8 0 Connector CN K Resistance 00K (K ) 00K 00K 00K 0 0K Tester Tester Resistance Resistance at 0 (K ) 0K.7 k (In case of TH heat exchanger thermistor) Resistance at Resistance at.7 k 0K. k TH TH.8K.0K 0K.7K.8K.7K Temperature( ) Temperature( ) TH Compressor thermistor TH Heat exchanger thermistor TH Outdoor air temperature thermistor TH Suction thermistor TH -way valve thermistor Thermistor Compressor thermistor Heat exchanger thermistor Outdoor air temperature thermistor Suction thermistor -way valve thermistor No. TH TH TH TH TH Connector No. () - No. () No. () - No. () No. () - No. () No. (7) - No. (8) No. (9) - No. (0) Color Red Orange Green Black Yellow Before measuring resistance, disconnect connectors from PWB. [] HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY. Cooling in 0 Hz fixed mode To operate the outdoor independently, short-circuit the sections indicated by arrows in the diagram below with an adapter, and apply 0 VAC between () and (N) on the terminal board of the outdoor. This allows the outdoor to be operated in cooling mode independently. (Do not operate the outdoor in this condition for an extended period of time.) C0 C9 (L) Connect with IC clip Test mode cooling at 0 Hz Short-circuit negative terminal of capacitor (C) and jumper wire (JP) using IC clip, etc.

26 AEXGRN [] GENERAL TROUBLESHOOTING CHART. Indoor does not turn on Main cause Inspection method Normal value/condition Remedy Cracked PWB. Check visually. There should be no cracking in PWB Replace PWB. (Cracked pattern) or pattern. Open-circuit in FU (0 V, A), FU (0 V, A) Check melting of FU, FU. There should be no open-circuit. Replace PWB.. Indoor fan does not operate Main cause Inspection method Normal value/condition Remedy Open-circuit in heat Measure thermistor resistance (dismount Refer to THERMISTOR TEMPERA- Replace thermistor. exchanger thermistor (TH) (in heating operation) for check). TURE CHARACTERISTICS There should be no open-circuit or Replace thermistor. faulty contact. Disconnected heat exchanger thermistor (TH) (in heating operation) Inspect connector on PWB. Check thermistor installation condition. Thermistor should not be disconnected. Install correctly.. Indoor fan speed does not change Main cause Inspection method Normal value/condition Remedy Remote control not designed to allow fan speed change. Check operation mode. Fan speed should change except during dehumidifying operation, ventilation, light dehumidifying operation, internally normal operation Explain to user.. Remote control signal is not received Main cause Inspection method Normal value/condition Remedy Batteries at end of service life. Measure battery voltage.. V or higher (two batteries in series Install new batteries. connection) Batteries installed incorrectly. Check battery direction. As indicated on battery compartment. Install batteries in indicated direction. Lighting fixture is too close, or fluorescent lamp is burning out. Turn off light and check. Signal should be received when light is turned off. Change light position or install new fluorescent lamp. Use Sevick light (Hitachi). Check if Sevick light (Hitachi) is Signal may not be received sometimes Replace light or change position. used. due to effect of Sevick light. Operating position/angle is inappropriate. Operate within range specified in manual. Signal should be received within range specified in manual. Explain appropriate handling to user. Open-circuit or short-circuit in wiring of light receiving section. Check if wires of light receiving section are caught. Wires of light receiving section should not have any damage caused by pinching. Replace wires of light receiving section. Defective light receiving. Dew condensation on light receiving.. Louvers do not move Check signal receiving circuit (measure voltage between terminals and of connector BCNB). Check for water and rust. Tester indicator should move when signal is received. Signal should be received within range specified in manual. Replace PWB. Take moisture-proof measure for lead wire outlet of light receiving section. Main cause Inspection method Normal value/condition Remedy Caught in sliding section. Operate to see if louvers are caught in place. Louvers should operate smoothly. Remove or correct catching section. Disconnected connector (DCNC, Inspect connectors. Connectors or pins should not be disconnected. Install correctly. DCND on relay PWB, louver motor side) Contact of solder on PWB (connector section on PWB) Check visually. There should not be solder contact. Correct contacting section.