INDOOR UNIT No. OBH802 SERVICE MANUAL Models MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA - U1 - U1 - U1 Outdoor unit service manual MXZ-C NA, MXZ-C NAHZ Series (OBH702, OCH573) CONTENTS MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA 1. TECHNICAL CHANGES ······························2 2. PART NAMES AND FUNCTIONS··················3 3. SPECIFICATION ········································4 4. OUTLINES AND DIMENSIONS ·····················6 5. WIRING DIAGRAM ·····································7 6.
Use the specified refrigerant only Never use any refrigerant other than that specified. Doing so may cause a burst, an explosion, or fire when the unit is being used, serviced, or disposed of. Correct refrigerant is specified in the manuals and on the spec labels provided with our products. We will not be held responsible for mechanical failure, system malfunction, unit breakdown or accidents caused by failure to follow the instructions. Prepare the proper tools.
2 PART NAMES AND FUNCTIONS INDOOR UNIT MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA Horizontal vane Vertical vane Air inlet Intake grille Air outlet $LU FOHDQLQJ ¿OWHU (Anti-Allergy Enzyme ILOWHU RSWLRQ $LU ¿OWHU $LU SXULI\LQJ ¿OWHU Display section Safety strings Open the display cover Spec name plate Remote control receiving section Emergency operation switch Operation indicator lamp ACCESSORIES MODELS Alkaline battery (AAA) for remote controller Drain hose (with insulation) Special washer (with cushio
3 SPECIFICATION 1. Multi connection Indoor model Power supply V, phase, Hz Max. fuse size (time delay)/ Disconnect switch A Airflow High - Med. - Low - SLow Sound level High - Med.
3-1. OPERATING RANGE (1) POWER SUPPLY Rated voltage Guaranteed voltage (V) 208/230 V 1 phase 60 Hz Indoor unit Min. 187 208 230 Max. 253 (2) OPERATION *The operating range of the outdoor unit depends on the connected outdoor unit.
4 OUTLINES AND DIMENSIONS Unit: inch MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA INDOOR UNIT OBH802 6
5 WIRING DIAGRAM INDOOR UNIT MLZ-KP09NAMLZ-KP12NA- MLZ-KP18NA- OBH802 U1 U1 U1 7
6 REFRIGERANT SYSTEM DIAGRAM INDOOR UNIT MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA Refrigerant pipe Ø3/8(Ø9.52) (with heat insulator) Indoor heat exchanger Indoor coil thermistor RT12 (main) Unit: inch(mm) Refrigerant pipe Ø1/2(Ø12.
7 SERVICE FUNCTIONS MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA 7-1. TIMER SHORT MODE • For service, the following set time can be shortened by bridging the timer short mode point on the electronic control P.C. board. (Refer to 10-7.) • The set time for the ON/OFF timer can be reduced to 1 second for each minute. • After the breaker is turned on, the time for starting the compressor, which normally takes 3 minutes, can be reduced to 3 seconds. Restarting the compressor, which takes 3 minutes, cannot be reduced.
7-3. AUTO RESTART FUNCTION When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed are memorized by the indoor electronic control P.C. board. “AUTO RESTART FUNCTION” automatically starts operation in the same mode just before the shutoff of the main power. Operation If the main power has been cut, the operation settings remain. After the power is restored, the unit restarts automatically according to the memory.
7-4. P.C. BOARD MODIFICATION FOR CHANGING AIRFLOW VOLUME Change dip switch SW3 setting according to the height of ceiling. Dip switch SW3 Normal Increase airflow volume Ceiling height 8.0 ft. (2.4 m) or below above 8.0 ft. (2.4 m) and 9.0 ft. (2.7 m) or below NOTE: When the ceiling is above 9.0 ft. (2.7 m), airflow volume may be insufficient even with the Dip switch (SW3) set to "increase airflow". How to change Dip switch (SW3) setting (Factory setting is normal) 1.
8 MICROPROCESSOR CONTROL MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA WIRELESS REMOTE CONTROLLER Signal transmitting section Operate the remote controller in the area where signal is received, and beep is heard. Distance of signal: About 20 ft. (6 m) Beep(s) is (are) heard from the indoor unit when the signal is received.
8-1. COOL ( ) OPERATION (1) Press STOP/OPERATE(OFF/ON) button. OPERATION INDICATOR lamp of the indoor unit turns on with a beep tone. (2) Select COOL mode with OPERATION SELECT button. (3) Press TEMPERATURE buttons TEMP or button to select the desired temperature. The setting range is 61 - 88°F (16 - 31°C). 1. Coil frost prevention The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the coil from frosting.
NOTE 2 FOR MULTI SYSTEM AIR CONDITIONER OUTDOOR UNIT: MXZ series Multi system air conditioner can connect 2 or more indoor units with one outdoor unit. • When you try to operate 2 or more indoor units with one outdoor unit simultaneously, one for the cooling and the others for heating, the operation mode of the indoor unit that operates first is selected. Other indoor units cannot operate, and operation indicator lamp flashes as shown in the figure below.
(6) SWING ( ) mode By selecting SWING mode with VANE CONTROL button, the horizontal vanes swing vertically. When COOL, DRY or FAN mode is selected, only the upper vane swings. (7) Cold air prevention in HEAT operation The horizontal vane position is set to Upward. (8) ECONO COOL ( ) operation (ECONOmical operation) When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 4°F(2°C) higher by microprocessor.
8-8. TIMER OPERATION 1. How to set the time (1) Check that the current time is set correctly. NOTE: Timer operation will not work without setting the current time. Initially “0:00” blinks at the current time display of TIME MONITOR, so set the current time correctly with CLOCK SET button. How to set the current time (a) Press the CLOCK set button. (b) Press the TIME SET buttons ( and ) to set the current time.
8-9. WEEKLY TIMER OPERATION • A maximum of 4 ON or OFF timers can be set for individual days of the week. • A maximum of 28 ON or OFF timers can be set for a week. E.g. : Runs at 75°F (24°C) from waking up to leaving home, and runs at 81°F (27°C) from getting home to going to bed on weekdays. Runs at 81°F (27°C) from waking up late to going bed early on weekends.
button to complete and transmit the weekly timer setting. (4) Press * which was blinking goes out, and the current time will be displayed. NOTE: • Press button to transmit the setting information of weekly timer to the indoor unit. Point the remote controller toward the indoor unit for 3 seconds. • When setting the timer for more than one day of the week or one number, button once after all the settings are complete. All the weekly timer settings will be saved. setting.
8-11. SLEEP ( ) OPERATION 1. How to set SLEEP operation (1) Press STOP/OPERATE (OFF/ON) button. (2) Select COOL, DRY, HEAT or FAN mode. (3) Press SLEEP ( ) button. (Increase) and (4) PRESS TEMPERATURE buttons [ operation. Fan speed: AUTO Horizontal vane: Position set on the remote controller Operation indicator lamp: Dimly lit • Once the above procedure is completed, the settings will be saved.
8-12. EMERGENCY/TEST OPERATION In the case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the right side of the indoor unit. Emergency operation is available when the remote controller is missing or has failed, or the batteries in the remote controller are running down. The unit will start and OPERATION INDICATOR lamp will light up. The first 30 minutes of operation is the test run operation. This operation is for servicing.
9 TROUBLESHOOTING MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA 9-1. CAUTIONS ON TROUBLESHOOTING 1. Before troubleshooting, check the following: 1) Check the power supply voltage. 2) Check the indoor/outdoor connecting wire for miswiring. 2. Take care of the following during servicing 1) Before servicing the air conditioner, be sure to turn off the unit first with the remote controller, and then after confirming the horizontal vane is closed, turn off the breaker and/or disconnect the power plug.
9-2. FAILURE MODE RECALL FUNCTION Outline of the function This air conditioner can memorize the abnormal condition which has occurred once. Even though LED indication listed on the troubleshooting check table (9-4.) disappears, the memorized failure details can be recalled. 1. Flow chart of failure mode recall function for the indoor/outdoor unit Operational procedure The cause of abnormality cannot be found because the abnormality does not recur.
2. Flow chart of the detailed outdoor unit failure mode recall function Operational procedure The outdoor unit might be abnormal. Check if outdoor unit is abnormal according to the following procedures. Make sure that the remote controller is set to the failure mode recall function. 1. Regardless of normal or abnormal, 2 short beeps are emitted as the signal is received.
3. Indoor unit failure mode table NOTE: Blinking patterns of this mode differs from the ones of Troubleshooting check table (9-4.). Left lamp of Right lamp of Abnormal point OPERATION OPERATION (Failure mode) INDICATOR lamp INDICATOR lamp Not lit Not lit Normal 1-time flash Not lit every 0.5-second 2-time flash 2.5-second OFF Not lit 3-time flash 2.
9-3. INSTRUCTION OF TROUBLESHOOTING Start Indoor unit operates. Outdoor unit does not operate. Outdoor unit operates only in Test Run operation. 1 Check room temperature thermistor. Refer to 9-7. "TEST POINT DIAGRAM AND VOLTAGE". Indoor unit operates. Outdoor unit does not operate normally. Outdoor unit does not operate even in Test Run operation. 1 Unit does not operate normal operation in COOL or HEAT mode. Refer to "How to check inverter/ compressor". Refer to "Check of R.V. coil".
9-4. TROUBLESHOOTING CHECK TABLE OPERATION INDICATOR Lit Blinking · Flashing of OPERATION INDICATOR lamp (left-hand side lamp) indicates abnormalities. Not lit NOTE: Before taking measures, make sure that the symptom reappears for accurate troubleshooting. Self check table No. Abnormal point 1 Miswiring or serial signal Operation indicator lamp Left lamp flashes. 0.5-second ON Symptom Condition Remedy Indoor unit and outdoor unit do not operate.
OPERATION INDICATOR Lit Blinking · Flashing of OPERATION INDICATOR lamp (right-hand side lamp) indicates abnormality. · OPERATION INDICATOR lamp (left-hand side lamp) is lighted. Not lit No. 1 Abnormal point MXZ type Operation mode setting Operation indicator lamp Right lamp flash 2.5-second OFF Symptom Condition Outdoor unit operates but indoor unit does not operate.
9-6. TROUBLESHOOTING FLOW When the left lamp of OPERATION INDICATOR lamp flashes 3 times and the right lamp of OPERATION INDICATOR lamp is not lighted. Indoor fan does not operate. A Check of indoor fan motor The indoor fan motor error has occurred, and the indoor fan does not operate. Turn OFF the power supply. Pay attention to the high voltage on the fan motor connector CN211.
Indoor unit operates by pressing EMERGENCY OPERATION switch, but does not operate with the remote controller. B Check of remote controller,receiver P.C. board and indoor electronic control P.C. board Check if the remote controller is exclusive for this air conditioner. Press STOP/OPERATE (OFF/ON) button on the remote controller. Is LCD display on the remote controller visible? Yes *1 Replace the batteries. (Refer to 9-1.4.
The unit cannot be operated with the remote controller. Also, OPERATION INDICATOR lamp does not light up by pressing EMERGENCY OPERATION switch. C Check of indoor electronic control P.C. board and indoor fan motor Turn OFF the power supply. Remove indoor fan motor connector CN211 and vane motor connector CN151 from the indoor electronic control P.C. board and turn ON the power supply. Turn OFF the power supply. Measure the resistance between CN211 and of the indoor fan motor connector.
When the left lamp of OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second. Outdoor unit does not operate. D How to check miswiring and serial signal error Turn OFF the power supply. Is there rated voltage of 208/230 V AC in the power supply? No Check the power supply. Yes Turn ON the power supply. Is there 208/230 V AC between outdoor terminal block S1 and S2? No Check the wiring. Yes Press EMERGENCY OPERATION switch once.
When the left lamp of OPERATION INDICATOR lamp flashes 9-time. Indoor unit and outdoor unit do not operate. E Check of float sensor Turn OFF the power supply and check connectors CN145 and CN1N1 visually. Yes Are there abnormality in the soldering part of connectors? Are the lead wires disconnected? Connect the lead wire. Yes Replace the indoor electronic control P.C. board. No No Disconnect float sensor from CN145 of indoor electronic control P.C. board.
F Electromagnetic noise enters into TV sets or radios Is the unit grounded? Yes Is the distance between the antennas and the indoor unit within 9.91 ft. (3m), or is the distance between the antennas and the outdoor unit within 9.91 ft. (3m)? No Ground the unit. No Extend the distance between the antennas and the indoor unit, and/or the antennas and the outdoor unit. Yes Is the distance between the TV sets or radios and the indoor unit within 3.28 ft.
9-7. TEST POINT DIAGRAM AND VOLTAGE Factory setting (Do not change the setting.) MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA Indoor electronic control P.C. board R111 CN1N1 Drain pump CN202 CN145 Float sensor Serial signal NR11 Varistor ON SW101 1 2 3 4 5 6 OFF F11 FUSE T3.15AL250V CN201 Power supply input 208/230 V AC CN1M1 Display P.C.
10 DISASSEMBLY INSTRUCTIONS The terminal which has the locking mechanism can be detached as shown below. There are following 2 types of the terminal with locking mechanism. The terminal without locking mechanism can be detached by pulling it out. Check the shape of the terminal before detaching. (1) Slide the sleeve and check if there is a locking lever or not. (2) The terminal with the connector shown below locking mechanism.
OPERATING PROCEDURE PHOTOS/FIGURES Figure 5 2. Removing the grille (1) Remove the intake grille. (2) Remove the fixing screws for side panels (2 screws) on the left and right sides (Figure 5). (3) Open the side panels on the left and right sides. Remove the safety strings from the grille and remove the side panels (Figure 5). (4) Open the horizontal vane completely. (5) Remove the screw cap in the center of air outlet (Figure 5).
OPERATING PROCEDURE PHOTOS/FIGURES Figure 9 (7) Install the screw cap. (8) After attaching the safety strings for the left and right side panels to the grille, install the side panels (Figure 9). NOTE: Make sure that the tabs of the side panels securely fit into place (Figure 9). NOTE: Open the display cover to make sure the positioning marks are aligned. NOTE: Make sure that there are no gaps between the emergency operation switch and the side panel (Figure 10)...
OPERATING PROCEDURE PHOTOS/FIGURES Photo 2 3. Removing the indoor electric control P.C. board, the receiver P.C. board and the display P.C. board Drain pan Fixing screw of the electrical box (1) Remove the intake grille. (2) Remove the side panel (L). (3) Remove the electrical cover and (4 fixing screws) (Photo 2). (4) Partially slide the indoor electronic control P.C. board out. (5) Disconnect all the connectors and lead wires on the board to remove the indoor electric control P.C. board.
OPERATING PROCEDURE PHOTOS/FIGURES 6. Removing the drain pump and float sensor Photo 5 Connector of the drain pump (1) Remove the grille. (2) Remove the drain pan. (3) Disconnect the connector of the drain pump (Photo 5). (4) Disconnect the connector of the float sensor (Photo 5). (5) Remove the drain hose (Photo 5). (6) Remove the drain pump assembly (2 fixing screws) (Photo 5). (7) Remove the drain pump cover (2 fixing screws) (Photo 5).
HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN © Copyright 2018 MITSUBISHI ELECTRIC CORPORATION Published in Mar. 2018 No. OBH802 Made in Japan Specifications are subject to change without notice.
