•Test point of 12 V DC has been corrected. OBH902 is void. INDOOR UNIT No. OBH902 REVISED EDITION-A SERVICE MANUAL Models MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG Outdoor unit service manual MUZ-RW•VG Series (OBH903) CONTENTS 1. TECHNICAL CHANGES ······························3 2. PART NAMES AND FUNCTIONS ··················4 3.
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.
The following models may be connected to the MUZ-RW·VGHZ series after once connected to the MXZ series and operated, for example because of relocation. In that case, the MUZ-RW·VGHZ series outdoor units will not operate without taking a step. Follow the procedure "Deleting the memorized abnormal condition" described in 10-2.1. MSZ-RW25VG - MSZ-RW35VG - MSZ-RW50VG - 1.
PART NAMES AND FUNCTIONS MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG Air purifying device Wi-Fi module Front panel Emergency operation Air inlet switch Air ﬁlter i-see sensor Horizontal vane Deodorizing ﬁlter, black or V Blocking Air outlet filter, green, option Spec name plate Remote control...
NOISE CRITERIA CURVE MSZ-RW25VG MSZ-RW35VG FAN SPEED FUNCTION SPL(dB(A)) LINE FUNCTION SPL(dB(A)) FAN SPEED LINE COOLING COOLING Super High Super High HEATING HEATING NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 NC-20 NC-20 NC-10 NC-10 1000 2000 4000...
SERVICE FUNCTIONS MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG 8-1. 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.
8-4. 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.
8-5. Wi-Fi MODULE SETTING UP This Wi-Fi module communicates the status information 3-1. Setting up in WPS-PUSH mode and controls the commands from the MELCloud by WPS-Push mode To enter the mode connecting to an indoor unit. (1) Hold down the Temperature Front panel 5 seconds.
3-2. Setting up in Access Point mode Complete the setting up in the Access Point mode within 3-2.3. Register the information of the router on the air 10 minutes. conditioner. Access Point mode In the displayed window, select Dynamic in To enter the mode DHCP (*1)and enter the information of router, (1) Hold down the Temperature...
• This Wi-Fi module should not be installed and • Make sure that DHCP is enabled, or check IP connected to any Mitsubishi Electric system which is address setting of the Wi-Fi module. to provide application critical cooling or heating.
8-6. CHANGING THE CORRECTION VALUE OF THE ROOM TEMPERATURE (THE INLET TEMPERATURE) The correction value of the room temperature can be adjusted in the range of 2 to 5 °C with the remote controller. Normally, the temperature at the room temperature sensor might become higher than that around feet because warm air tends to accumulate around an indoor unit during heating operation.
2. Writing the correction value of the room temperature on the wiring diagram After setting the correction value of the room temperature (the inlet air temperature), follow 11. DISASSEMBLY INSTRUCTIONS to disassemble the indoor unit, and then write the correction value (any of 3, 4, or 5) on the wiring dia- gram with a ballpoint pen, etc.
8-7. ADJUSTING POSITION GAPS BETWEEN THE LEFT AND RIGHT HIRIZONTAL VANES AT UPPER AND LOWER SIDE When there are position gaps between the left and right horizontal vanes at upper and lower side, follow the pro- cedure below for the service. 1.
MICROPROCESSOR CONTROL MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG WIRELESS REMOTE CONTROLLER Signal transmitting section Distance of signal : About 6 m Beep(s) is (are) heard from the indoor unit when the signal is received. FAN speed control button Battery replacement indicator Operation select button...
MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG WIRELESS REMOTE CONTROLLER Signal transmitting section Distance of signal : About 6 m Beep(s) is (are) heard from the indoor unit when the signal is received. FAN speed control button Battery replacement indicator Operation select button DRIVE button...
9-1. COOL ( ) OPERATION (1) Press OFF/ON (stop/operate) 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 button to select the desired temperature. The setting range is 16 - 31°C. 1.
NOTE 1: If 2 or more indoor units are operating in multi system, there might be a case that the indoor unit, which is operating in (AUTO), cannot change over to the other operating mode (COOL ↔ HEAT) and becomes a state of standby. Refer to NOTE 2 “FOR MULTI SYSTEM AIR CONDITIONER”.
(7) 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. (8) Cold air prevention in HEAT operation The horizontal vane position is set to Upward. NOTE: When 2 or more indoor units are operated with multi outdoor unit, even if any indoor unit turns thermostat off, this control does not work in the indoor unit.
9-7. 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 button. How to set the current time (a) Press the CLOCK button.
9-8. 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. NOTE: The simple ON/OFF timer setting is available while the weekly timer is on. In this case, the ON/OFF timer has priority over the •...
(4) Press button to complete and transmit the weekly timer setting. which was blink- ing 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.
ABSENCE DETECTION ( ) This function automatically changes the operation to No occupancy energy-saving mode or No occupancy Auto-OFF mode when nobody is in the room. (1) To activate this No occupancy energy-saving mode, press SENSOR button until appears on the operation display of the remote controller.
9-11. NIGHT MODE ( ) OPERATION NIGHT MODE changes the brightness of the operation indicator, disables the beep sound and limits the noise level of the outdoor unit. (1) Press NIGHT MODE button during operation to activate NIGHT mode ( ). •...
9-15. CIRCULATOR OPERATION (MSZ-RW25/35/50VG - only) In case the indoor temperature reaches the setting temperature, the outdoor unit stops and the indoor unit starts FAN oper- ation to circulate the indoor air. The setting of fan speed and airflow direction can be changed. The outdoor unit starts operation automatically when the indoor temperature drops below the setting temperature.
9-17. EMERGENCY/TEST OPERATION In the case of test run operation or emergency operation, use the emer- Operation mode COOL/HEAT gency operation switch on the right side of the indoor unit. Emergency Set temperature 24°C operation is available when the remote controller is missing or has failed, Fan speed Med.
TROUBLESHOOTING MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG 10-1. 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 main 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.
10-2. 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 (10-4.) disappears, the memorized failure details can be recalled. 1.
2. Flow chart of AIR PURIFYING power failure mode and i-see SENSOR failure mode recall function Operational procedure The air purifying device or i-see SENSOR might be abnormal. Check if the air purifying device or i-see SENSOR is abnormal according to the following procedures. Make sure that the remote controller is set to the failure mode recall function.
4. Table of indoor unit failure mode recall function (When recalled at a set temperature of 24°C) Abnormal point POWER lamp Condition Remedy (Failure mode) Not lit Normal — — The room temperature thermistor short or 1-time blink every Room temperature Refer to the characteristics of the room temperature open circuit is detected every 8 seconds dur- 0.5-second...
10-3. INSTRUCTION OF TROUBLESHOOTING *2 There is possibility that diesel explosion may occur due to the air mixied in the refrigerant circuit. 1. Check of the unit. First, ensure that there are no leakage points on the valves, flare connec- *1 "Test Run operation"...
2. Check of Wi-Fi module Follow the procedure below if the air conditioner cannot be monitored or controlled with a device such as a smartphone. Did the LED indication blink 10 times after you There is a problem in a communication between the air selected the setting of the Wi-Fi module and the conditioner and the Wi-Fi module.
10-4. TROUBLESHOOTING CHECK TABLE Before taking measures, make sure that the symptom reappears for accurate troubleshooting. When the indoor unit has started operation and detected an abnormality of the following condition (the first detection after the power ON), the indoor fan motor turns OFF and OPERATION INDICATOR lamp blinks. •...
OFF even if the AIR PURIFYING power PURIFYING power". not operate. operation is turned OFF by remote controller. control 10-5. TROUBLESHOOTING CRITERION OF MAIN PARTS MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG Part name Check method and criterion Figure Measure the resistance with a tester.
10-6. TROUBLESHOOTING FLOW 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 enough attention to the high voltage on the fan motor connector CN211. Turn ON the power supply, wait 5 seconds or more, and then press the emergency operation switch.
B Check of remote controller and indoor electronic control P.C. board NOTE: Check if the remote controller is exclusive for this air conditioner. Press OFF/ON (stop/operate) but- ton on the remote controller. 1 Look at the image of the signal transmitting section of the remote controller through the monitor of a digital camera or a camera phone.
C Check of indoor P.C. board and indoor fan motor Turn OFF the power supply. Remove indoor fan motor connector CN211 from indoor power P.C. board and vane Measure the resistance of indoor fan Short circuit: motor connector CN151 from the indoor motor.
D How to check miswiring and serial signal error MUZ Type Turn OFF the power supply. Is there rated voltage in the power supply? Check the power supply. Check for incorrect indoor-outdoor connecting wiring. Was the indoor unit ever connected to the Multi (MXZ) series and operated (turned on)? The connection information to the Multi series is stored...
MXZ Type Turn OFF the power supply. Is there rated voltage in the power supply? Check the power supply. LED indication for communication status Communication status is indicated by the Turn ON the power supply. LED. Unit status Is there rated voltage between outdoor terminal block S1 and S2? Check the wiring.
E Check of AIR PURIFYING power After performing the check, make sure to release the failure mode recall function. High voltage (approximately 5.8kV) is generated during AIR PURIFYING power operation. Turn ON the power supply. Pay careful attention and never touch the air purifying device and the high-voltage lead part.
F Electromagnetic noise enters into TV sets or radios Is the unit earthed? Earth the unit. Is the distance between the antennas Extend the distance between the antennas and and the indoor unit within 3 m, or is the the indoor unit, and/or the antennas and the distance between the antennas and the outdoor unit.
10-7. TEST POINT DIAGRAM AND VOLTAGE Indoor power P.C. board, Indoor electronic control P.C. board, Display and receiver P.C. board, Switch buzzer P.C. board MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG Indoor power P.C. board Resistor (R111) Varistor (NR11) Connector Terminal Indoor fan motor...
Locking lever lever. Connector MSZ-RW25VG MSZ-RW35VG MSZ-RW50VG : Indicates the visible parts in the photos/figures. NOTE: Turn OFF the power supply before disassembly. : Indicates the invisible parts in the photos/figures. OPERATING PROCEDURE PHOTOS/FIGURES Photo 1 1.
OPERATING PROCEDURE PHOTOS/FIGURES How to install the front panel (Photos 1, 2) Figure 1 (1) Attach the horizontal vanes (upper R/L) and (lower R/L) (2) Install the front panel to the indoor unit. (3) Push the locations indicated by the arrows firmly Click to close the front panel (Figure 1).
OPERATING PROCEDURE PHOTOS/FIGURES 2. Removing the indoor electrical box Photo 5 (Photos 5, 6, 7, 8) (1) Remove the front panel, the horizontal vanes (uppler R/ L), (lower R/L), the corner boxes (R) (L), and the panels (U) (R) (L) (refer to section 1). (2) Remove the erath wire.
OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing the indoor electronic control P.C. Photo 8 (Enlarged view of the indoor board, the indoor power P.C. board, the indoor electronic control P.C.bard) terminal block, and the room temperature ther- mistor (1) Remove the electrical box (Refer to section 2). CN201 Indoor power P.C.
OPERATING PROCEDURE PHOTOS/FIGURES 4. Removing the DISPLAY AND i-see SENSOR ASSEMBLY, the display P.C. board, and the receiver P.C. board (Photo 9). (1) Remove the DISPLAY AND i-see SENSOR ASSEMBLY (Refer to section 2). (2) Cut off the cable tie of the lead wires of the DISPLAY AND i-see SENSOR ASSEMBLY at the back side of the display cover (Photo 9-2).
OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the Wi-Fi assembly (Photos 3,10) Photo 10 (1) Remove the front panel, horizontal vanes (upper R/L), (lower R/L), corner boxes (R) (L), and the panels (U) Wi-Fi assembly (R) (L). (2) Remove the screw of the V.A. clamp and remove the Catch V.A.
OPERATING PROCEDURE PHOTOS/FIGURES 6. Removing the horizontal vanes (R)(L) and the Photo 12 horizontal vane motors (R)(L) (Photos 8, 12, 13, 14) (1) Remove the front panel, horizontal vanes (upper R/L), (lower R/L), the corner boxes (R) (L), the panels (U) (R) (L), V.A.
OPERATING PROCEDURE PHOTOS/FIGURES 7. Removing the vertical vane motor units (R) (L) Photo 15 and the vertical vane motors (R) (L) (1) Remove the front panel, horizontal vanes (upper R/L) (lower R/L), the corner boxes (R) (L), the panels (U) (R) (L), V.A.
OPERATING PROCEDURE PHOTOS/FIGURES Removing the horizontal vane motor unit (L) and the vane Photo 18 motor (L) (vertical) (Photo 17, 18) (9) Remove the 3 screws of the horizontal motor unit (L) Vertical vane motor unit (L) indicated in (Photo 17). (10) Disengage the catch of the horizontal vane motor unit (L), and remove the horizontal vane motor unit (L).
OPERATING PROCEDURE PHOTOS/FIGURES Photo 19 8. Removing the air purifying device (Photo 19) NOTE: (1) Remove the front panel, the horizontal vanes (upper R/L), (lower R/L), the corner boxes (R) (L), the pan- Install the fan motor and lead wires in the former position when els (U) (R) (L), V.A.