OB404A--1.qxp 06.4.26 6:01 PM Page 1 Revision A: ● Remote controller model “KM04B” has been added. Please void OB404. SPLIT-TYPE, AIR CONDITIONERS INDOOR UNIT SERVICE MANUAL No. OB404 REVISED EDITION-A Wireless type Models MS-A18NDMS-A24NDMS-A30ND- S1 S1 S1 Outdoor unit service manual MU-A·ND Series (OB405) CONTENTS MS-A18ND MS-A24ND MS-A30ND 1. TECHNICAL CHANGES ····································2 2. PART NAMES AND FUNCTIONS······················2 3.
OB404A--1.qxp 06.4.26 6:01 PM Page 2 Revision A: • Remote controller model “KM04B” has been added. There are two remote controller models for “ S1 ”. (KP0B, KM04B) You can use the remote controller model “KP0B” and “KM04B”. The remote controller model “KM04B” is supplied as service parts for “ 1 S1 ”.
OB404A--1.qxp 06.4.26 6:01 PM Page 3 ACCESSORIES 1 2 3 4 5 6 7 8 9 MS-A18ND MS-A24ND MS-A30ND 1 7 1 2 2 1 1 2 Installation plate Installation plate fixing screw 4 x 25 mm Remote controller holder Fixing screw for 3 3.
OB404A--1.qxp 3 06.4.26 6:01 PM Page 4 SPECIFICATION MS-A18ND Indoor model MS-A24ND Cooling Single phase 220-230V, 60Hz Function Power supply Special remarks Fan motor Electrical data Capacity Air flow (High/Med./Low) Running current Power input Auxiliary heater Power factor Fan motor current Model Winding resistance(at 20:) Dimensions WOHOD Weight Air direction Sound level (High/Med./Low) Fan speed (High/Med.
06.4.26 6:01 PM OUTLINES AND DIMENSIONS MS-A18ND MS-A24ND MS-A30ND INDOOR UNIT Unit: mm Installation plate Indoor unit 98 7.5 173 98 414.5 414.5 258 325 Air in 791 56 253 Air out Insulation [28 19 162 58 Wireless remote controller 5 { { { Liquid line [ 6.35- 0.5m Gas line [ 12-0.43m Insulation [ 50 O.D 5 [ 32 I.D Installation plate for MS-A18ND Liquid line [ 9.52- 0.5m Gas line [ 12-0.43m Insulation [ 50 O.D [ 32 I.D for MS-A24ND Liquid line [ 9.52- 0.5m Gas line [ 16-0.
OB404A--1.qxp 5 06.4.26 6:01 PM Page 6 WIRING DIAGRAM MS-A18ND MS-A24ND INDOOR UNIT TO OUTDOOR UNIT CONNECTING 220-230V~ HIC1 CN201 2TBWHT F12 BLU BLU N BLU 1 2 4 52C CN 111 RT11 CN 121 NR11 220-230V~ C11 L RT12 3 3 2 1 BLU CN 112 BRN F11 SR141 1 3 4 3 BLK GRY YLW BRN WHT RED MF CN211 GRN/YLW CN 151 CN 102 15 MV2 MV2 MV1 CN 101 ELECTRONIC CONTROL P.C. BOARD 3 3 DISPLAY P.C. BOARD RECEIVER P.C. BOARD REMOTE CONTROLLER SYMBOL NAME NAME FUSE(3.
OB404A--1.qxp 06.4.26 6:01 PM Page 7 MS-A30ND INDOOR UNIT TO OUTDOOR UNIT CONNECTING TB 12V 3 N HIC1 3 2 1 BLU CN 151 C11 CN 102 15 F11 CN 101 3 MV2 MV2 MV1 CN 121 NR11 TAB12 BRN RT13 RT12 CN112 CN201 RED GRN/YLW 220-230V~ 2 4 3 2 1 SR141 1 3 4 3 BLK GRY YLW BRN WHT RED CN211 CN ELECTRONIC CONTROL P.C. BOARD 111 RT11 3 DISPLAY P.C. BOARD RECEIVER P.C. BOARD REMOTE CONTROLLER SYMBOL NAME NAME SYMBOL C11 INDOOR FAN CAPACITOR MV2 VERTICAL VANE MOTOR F11 FUSE(3.
OB404A--1.qxp 6 06.4.26 6:01 PM Page 8 REFRIGERANT SYSTEM DIAGRAM MS-A18ND Unit : mm INDOOR UNIT Refrigerant pipe [12.7 (with heat insulator) Indoor heat exchanger Main indoor coil thermistor RT12 Flared connection Distributor RT11 Room temperature thermistor Strainer #50 Flared connection Refrigerant pipe [6.35 (with heat insulator) MS-A24ND MS-A30ND INDOOR UNIT INDOOR UNIT Refrigerant pipe [15.
OB404A--1.qxp 06.4.26 6:01 PM 7 Page 9 SERVICE FUNCTIONS MS-A18ND MS-A24ND MS-A30ND 7-1. TIMER SHORT MODE For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board. The time will be shortened as follows. (Refer to 8-6.) Set time : 1-minute ➔ 1-second Set time : 3-minute ➔ 3-second It takes 3 minutes for the compressor to start operation. However, the starting time is shortened by short circuit of JPG and JPS. 7-2. P.C.
OB404A--1.qxp 06.4.26 6:01 PM Page 10 Table 1 1 unit operation 2 units operation 3 units operation 4 units operation No. 1 unit No modification Same as at left Same as at left Same as at left No. 2 unit – Solder J1 Same as at left Same as at left No. 3 unit – – Solder J2 Same as at left No. 4 unit – – – Solder both J1 and J2 How to set the remote controller exclusively for particular indoor unit.
OB404A--1.qxp 06.4.26 6:01 PM 8 Page 11 TROUBLESHOOTING MS-A18ND MS-A24ND MS-A30ND 8-1. Cautions on troubleshooting 1. Before troubleshooting, check the following: 1) Check the power supply voltage. 2) Check the indoor/outdoor connecting wire for mis-wiring. 2. Take care the following during servicing.
OB404A--1.qxp 06.4.26 6:01 PM Page 12 8-2. Instruction of troubleshooting Start Indoor unit operates. Outdoor unit doesn't operate. Outdoor unit operates in only Test Run operation. w Check room temperature thermistor. Refer to 8-6. "Test point diagram and voltage". MS-A30ND Flash on and off at 0.5-second intervals Cause: Indoor/ Outdoor unit • Mis-wiring MU-A30ND Outdoor unit doesn't operate even in Test Run operation.w Refer to "Check of outdoor unit".
OB404A--1.qxp 06.4.26 6:01 PM Page 13 8-3. Troubleshooting check table • The following indication applies regardless of shape of the indicator. · Flashing of the OPERATION INDICATOR lamp (the left-hand side lamp) indicates possible abnormalities. · The OPERATION INDICATOR lamp (the left-hand side lamp) is lighting during Not lighted normal operation. Operation Indicator Lighted Before taking measures, make sure that the symptom reappears for accurate troubleshooting. Self check table No.
OB404A--1.qxp 06.4.26 6:01 PM Page 14 8-4. Trouble criterion of main parts MS-A18ND MS-A24ND MS-A30ND INNER PROTECTOR 135i 5: OPEN 86i15: CLOSE Horizontal vane motor(MV1) Vertical vane motor(MV2) Motor part Measure the resistance with a tester. (Part temperature 10°C ~ 30°C) Refer to 8-6. “Test point diagram and voltage”, “Indoor electronic control P.C. board”, the chart of thermistor. Measure the resistance between the terminals with a tester.
OB404A--1.qxp 06.4.26 6:01 PM Page 15 8-5. Troubleshooting flow When OPERATION INDICATOR lamp flashes 3-time. Indoor fan motor doesn’t operate. A Check of indoor fan motor Turn OFF the power supply. Check connector CN211 visually. No Yes Are lead wires connected? Is soldered point of the connector correctly soldered? No Yes Resolder it. Reconnect the lead wires. Disconnect lead wires from connector CN211 on the indoor electronic control P.C. board. Measure resistance between lead wires No.
OB404A--1.qxp 06.4.26 6:01 PM Page 16 The unit doesn’t operate with the remote controller. Also, the OPERATION INDICATOR lamp doesn’t light up by pressing the EMERGENCY OPERATION switch. C Check of indoor electronic control P.C. board Check both “parts side” and “pattern side” of the indoor electronic control P.C. board visually. 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.
OB404A--1.qxp 06.4.26 6:01 PM Page 17 When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second. Outdoor unit doesn’t operate. D How to check mis-wiring MS-A30ND w Short circuit of JPG and JPS on the indoor electronic control P.C. board enables self-check to be displayed in 3 seconds. Start • Turn ON the power supply. • Press EMERGENCY OPERATION switch once. When the unit has mis-wiring, in 3 minutes, OPERATION INDICATOR lamp on indoor unit flash on and off at 0.5 second intervals.
OB404A--1.qxp 06.4.26 6:01 PM Page 18 8-6. Test point diagram and voltage MS-A18ND MS-A24ND MS-A30ND Indoor electronic control P.C.board Varistor (NR11) Fan motor power supply 220-230V AC(CN211) } Power supply input 220-230V AC + Fuse (F11) 250V AC 3.
OB404A--1.qxp 9 06.4.26 6:01 PM Page 19 DISASSEMBLY INSTRUCTIONS <"Terminal with locking mechanism" Detaching points> The terminal which has the locking mechanism can be detached as shown below. There are two types ( Refer to (1) and (2)) 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.
OB404A--1.qxp 06.4.26 6:01 PM Page 20 OPERATING PROCEDURE PHOTOS 3. Removing the electrical box (1) Remove the front panel. (Refer to 1.) (2) Remove the electrical cover. (Refer to 2.) (3) Disconnect the connector of the indoor coil thermistor. (4) Disconnect the motor connector (CN211 and CN121) and the vane motor connector (CN151) on the electronic control P.C. board. (5) Remove the screw of ground wire. (6) Remove the fan motor lead wire and indoor coil thermistor from the electrical box.
OB404A--1.qxp 06.4.26 6:01 PM 10 Page 21 PARTS LIST (non-RoHS compliant) MS-A18ND MS-A24ND MS-A30ND 10-1. INDOOR UNIT STRUCTURAL PARTS 10-2. INDOOR UNIT HEAT EXCHANGER 1 2 11 3 4 CATCH 9 (See 10-5.) 7 5 SCREW CAP 12 13 6 8 10-1. INDOOR UNIT STRUCTURAL PARTS Part number that is circled is not shown in the illustration. No. 1 2 3 4 5 6 7 8 9 10 Part No.
OB404A--1.qxp 06.4.26 6:01 PM Page 22 PARTS LIST (non-RoHS compliant) MS-A18ND MS-A24ND MS-A30ND 10-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS 20 1 10-4. ACCESSORY AND REMOTE CONTROLLER 19 24 2 25 3 SLEEVE BEARING 4 12 17 11 ROOM TEMPERATURE THERMISTOR 5 6 13 18 10 7 FUSE 8 9 VARISTOR 14 15 16 10-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS Part numbers that are circled are not shown in the illustration. No.
OB404A--1.qxp 06.4.26 6:01 PM Page 23 PARTS LIST (non-RoHS compliant) 10-5. AIR CLEANING FILTER ● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity. ● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible. ● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet. ● DO NOT reuse AIR CLEANING FILTER even if it is washed.
OB404A--1.qxp 11 06.4.26 6:01 PM Page 24 RoHS PARTS LIST (RoHS compliant) MS-A18ND MS-A24ND MS-A30ND 11-1. INDOOR UNIT STRUCTURAL PARTS 11-2. INDOOR UNIT HEAT EXCHANGER 1 2 11 3 4 CATCH 9 (See 11-5.) 7 5 SCREW CAP 12 13 6 8 11-1. INDOOR UNIT STRUCTURAL PARTS No. RoHS Part number that is circled is not shown in the illustration. 1 2 3 4 5 6 7 8 9 10 G G G G G G G G G G Part No.
OB404A--1.qxp 06.4.26 6:01 PM Page 25 RoHS PARTS LIST (RoHS compliant) MS-A18ND MS-A24ND MS-A30ND 11-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS 20 1 11-4. ACCESSORY AND REMOTE CONTROLLER 19 24 2 25 3 SLEEVE BEARING 4 12 17 11 ROOM TEMPERATURE THERMISTOR 5 6 13 18 10 7 FUSE 8 9 VARISTOR 14 15 16 11-3. INDOOR UNIT FUNCTIONAL PARTS AND ELECTRICAL PARTS No.
OB404A--1.qxp 06.4.26 6:01 PM Page 26 RoHS PARTS LIST (RoHS compliant) 11-5. AIR CLEANING FILTER ● AIR CLEANING FILTER removes fine dust of 0.01 micron from air by means of static electricity. ● Normal life of AIR CLEANING FILTER is 4 months. However, when it becomes dirty, replace it as soon as possible. ● Clogged AIR CLEANING FILTER may reduce the air conditioner capacity or cause frost on the air outlet. ● DO NOT reuse AIR CLEANING FILTER even if it is washed.
OB404A--1.qxp 06.4.
OB404A--1.qxp 06.4.26 6:01 PM Page 28 TM HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN C Copyright 2005 MITSUBISHI ELECTRIC ENGINEERING CO.,LTD Distributed in May 2006. No.OB404 REVISED EDITION-A 106 Reprinted in Apr. 2005. No.OB404 100 Distributed in Mar. 2005. No.OB404 6 Made in Japan New publication, effective May 2006 Specifications subject to change without notice.
