Page 1: Table Of Contents
No. OCH480 REVISED EDITION-A utilized R410A TECHNICAL & SERVICE MANUAL [Model name] [Service Ref.] Revision: <Outdoor unit> • Errors in "3. MXZ-8B140VA SPECIFICATIONS" MXZ-8B140VA have been corrected in REVISED EDITION-A. MXZ-8B160VA • Some descriptions have MXZ-8B160VA been modified. MXZ-8B140YA • Please void OCH480.
Page 2: Safety Precaution
SAFETY PRECAUTION 1-1. ALWAYS OBSERVE FOR SAFETY Before obtaining access to terminal, all supply circuit must be disconnected. 1-2. CAUTIONS RELATED TO NEW REFRIGERANT Cautions for units utilizing refrigerant R410A Use new refrigerant pipes. Do not use refrigerant other than R410A. If other refrigerant (R22 etc.) is used, chlorine in refrige- Make sure that the inside and outside of refrige- rant can cause deterioration of refrigerant oil etc.
Page 3 [1] Cautions for service (1) Perform service after recovering the refrigerant left in unit completely. (2) Do not release refrigerant in the air. (3) After completing service, charge the cycle with specified amount of refrigerant. (4) When performing service, install a filter drier simultaneously. Be sure to use a filter drier for new refrigerant.
Page 4 (2) Cautions for refrigerant piping work New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working pressure of R410A is 1.6 times higher than that of R22, their sizes of flared sections and flare nuts are different.
Page 5: Overview Of Units
OVERVIEW OF UNITS 2-1. CONSTRUCTION OF SYSTEM MXZ-8B140VA/160VA MXZ-8B140YA/160YA Outdoor unit Rated Cooling 14.0 15.5 capacity (kW) Heating 16.0 18.0 Refrigerant R410A Type 15 ~ Type 100 Indoor unit CAUTION : The indoor unit which rated capability exceeds Capacity 10.0kW (100 type) can NOT be connected.
Page 6 2-2. SYSTEM OUTLINE The additional connection of the Branch Box together with employment of the compact trunk-looking outdoor unit can successfully realizes a long distance piping for big houses. Equipped with a microprocessor, the Branch Box can trans- late the transmission signal of indoor units to achieve the optimum control. 2-2-1.
Page 7 2-3. TYPICAL COMBINATION EXAMPLE Branch box is located INSIDE of condominium Branch box (Inside) Installing branch box indoors Only 1 piping is required between the outdoor and indoor offering a fine external view. ■ System example of 5 indoor units Branch box (5 branch type) Master Dining...
Page 8 2-4. INSTALLATION 2-4-1. Outdoor unit installation location For best performance, select proper position. ● Avoid places where combustible gas may be generated or leak. ● Avoid direct sunlight or other sources of heat. ● Install sunshade to protect the outdoor unit if direct sunlight hits the unit. ●...
Page 9 (2) When installing a single outdoor unit Minimum dimensions are as follows, except for Max., meaning Maximum dimensions, indicated. Refer to the figures for each case. ● Obstacles at rear only (Fig. 2-4) ● Obstacles at rear and above only (Fig. 2-5) ·...
Page 10 (3) When installing multiple outdoor units Leave 10 mm space or more between the units. ● Obstacles at rear only (Fig. 2-10) ● Obstacles at rear and above only (Fig. 2-11) • No more than 3 units must be installed side by side. In addition, leave space as shown. •...
Page 11 2-5. SIMPLIFIED PIPING SYSTEM Piping connection size The piping connection size differs according to the type and capacity of indoor units. Liquid (mm) 9.52 Match the piping connection size of branch box with indoor unit. If the piping connection size of branch box does not match the piping connection size of indoor unit, use optional different-diameter (deformed) joints to the branch box side.
Page 12: Specifications
SPECIFICATIONS MXZ-8B140VA MXZ-8B140YA kcal/h = kW MXZ-8B160VA MXZ-8B160YA Conversion formula: Btu/h = kW 3412 /min 35.31 MXZ-8B140VA MXZ-8B160VA MXZ-8B140YA MXZ-8B160YA Service Ref. Rated Cooling capacity 14.0 15.5 14.0 15.5 Rated power consumption 3.79 3.79 4.64 4.64 Operating current 17.30/16.55/15.86 17.82/17.05/16.33 5.82/5.53/5.33...
Page 13: Data
DATA 4-1. CORRECTING COOLING AND HEATING CAPACITY 4-1-1. Correcting Changes in Air Conditions (1) The performance curve charts (Figure 4-1, 4-2, 4-3, 4-4) show the change ratio of capacity and input (power consumption) according to the indoor and outdoor temperature condition when define the rated capacity (total capacity) and rated input under the standard condition in standard piping length (5 m) as “1.0”.
Page 14 0.70 0.70 0.65 0.65 Corrected piping length (m) Corrected piping length (m) Fig. 4-6 Heating capacity correction curve MXZ-8B140VA, MXZ-8B140YA, MXZ-8B160VA, MXZ-8B160YA Heating Capacity 0.95 (ratio) [%] Corrected piping length (m) (2) Method for Obtaining the Corrected Piping Length Corrected piping length = (Actual piping length between outdoor unit and the farthest indoor unit) + (0.30 o number of bends in the piping) (m)
Page 15: Noise Criterion Curves
4-2. NOISE CRITERION CURVES MICROPHONE UNIT 1.5m GROUND MXZ-8B140VA MXZ-8B160VA SPL(dB) SPL(dB) MODE LINE MODE LINE COOLING COOLING MXZ-8B140YA MXZ-8B160YA HEATING HEATING NC-70 NC-70 NC-60 NC-60 NC-50 NC-50 NC-40 NC-40 NC-30 NC-30 APPROXIMATE APPROXIMATE THRESHOLD OF THRESHOLD OF HEARING FOR...
Page 16: Outlines And Dimensions
OUTLINES AND DIMENSIONS MXZ-8B140VA MXZ-8B140YA MXZ-8B160VA MXZ-8B160YA unit : mm 2 SERVICE SPACE 3 FOUNDATION BOLTS 4 PIPING-WIRING DIRECTIONS 1 FREE SPACE (Around the unit) The diagram below shows a basic Dimensions of space needed Please secure the unit firmly Piping and wiring connections example.
Page 17: Wiring Diagram
WIRING DIAGRAM MXZ-8B140VA MXZ-8B160VA 63HS C. B. is the switch position. t° t° t° t° SYMBOL NAME Terminal Block <Power Supply, Branch Box> CNF1 (WHT) Motor for Compressor CNIT TH7/6 63HS MF1, MF2 Fan Motors (RED) (RED) (WHT) (WHT) (WHT) Solenoid Valve <Four-Way Valve>...
Page 18 MXZ-8B140YA MXZ-8B160YA 63HS SYMBOL NAME Terminal Block <Power Supply> C. B. is the switch position. Terminal Block <Branch Box> t° t° t° t° Motor for Compressor CNF1 MF1, MF2 Fan Motors (WHT) 21S4 Solenoid Valve <Four-Way Valve> CNIT TH7/6 63HS (RED) High Pressure Switch (RED)
Page 19: Necessary Conditions For System Construction
NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION REFRIGERANT SYSTEM DIAGRAM MXZ-8B140VA MXZ-8B140YA MXZ-8B160VA MXZ-8B160YA High pressure sensor Condenser / evaporator discharge pressure sensor temperature thermistor Room temperature Check valve 63HS thermistor (TH1 or RT11) (TH5 or RT12) Bypass valve(SV2) (High Pressure) 4-way valve...
Page 20 ■ Pipe size (Branch box-Indoor unit) *Case of M series or S series Indoor unit Indoor unit type (kW) Liquid 6.35 6.35 9.52 9.52 6.35 6.35 6.35 6.35 6.35 6.35 Pipe size (mm) 9.52 9.52 9.52 9.52 9.52 9.52 12.7 15.88 15.88 15.88...
Page 21: Troubleshooting
TROUBLESHOOTING 8-1. TROUBLESHOOTING <Error code display by self-diagnosis and actions to be taken for service (summary)> Present and past error codes are logged and displayed on the wired remote controller and control board of outdoor unit. Actions to be taken for service, which depends on whether or not the trouble is reoccurring at service, are summarized in the table below.
Page 22 8-2. CHECK POINTS FOR TEST RUN 8-2-1. Before test run ● Turn on the main power switch more than 12 hours before starting operation. Starting operation just after turning on the power switch can severely damage the internal parts. Keep the main power switch turned on during the operation season. ●...
Page 23 (2) Using SW4 in outdoor unit In case of the test run from outdoor unit, all indoor units operate. Therefore, you cannot detect any erroneous con- nection of refrigerant pipes and the connecting wires. If it aims at detection of any erroneous connection, be sure to carry out the test run from remote controller with reference to "(1) Using remote controller."...
Page 24: Self-Diagnosis Action Table
8-3. SELF-DIAGNOSIS ACTION TABLE <Abnormalities detected when the power is put on> (Note 1) Refer to indoor unit section for code P and code E. Abnormal point and detection method Judgment and action Error Code Case 1 No voltage is supplied to termi- 1 Check following items.
Page 25 Abnormal point and detection method Case Judgment and action Error Code 1 Contact failure or miswiring of 1 Check disconnection or looseness or polar- Indoor–branch box/branch box–outdoor unit connector miswiring, excessive indoor/outdoor unit connecting ity of indoor –branch box/branch box–outdoor number of units wire unit connecting wire of indoor and outdoor...
Page 26 Abnormal point and detection method Case Judgment and action Error Code 1 Contact failure or miswiring of 1 Check disconnection or looseness or polar- Faulty connection of LEV For the connection of P100 indoor unit(s), indoor/outdoor unit connecting ity of indoor –branch box/branch box–outdoor the connecting wire(s) must be connected wire unit connecting wire of indoor and outdoor...
Page 27 <Abnormalities detected while unit is operating> Abnormal point and detection method Judgment and action Error Code Case 1) Short cycle of indoor unit (1) High-pressure switch (63H) operated 1)~6) Check indoor unit and repair defect. Abnormal if high-pressure switch 63H oper- 2) Clogged filter of indoor unit ated ( w ) during compressor operation.
Page 28 Error Code Abnormal point and detection method Case Judgment and action 1 Overheated compressor opera- 1 Check intake superheat. (1) High discharging temperature Abnormal if compressor temperature tion caused by shortage of Check leakage of refrigerant. thermistor (TH4) exceeds 125: or refrigerant Charge additional refrigerant.
Page 29 Abnormal point and detection method Case Judgment and action Error Code 1 Check the connector’s contact and the electric 1One or more connectors on (1) Open/short circuit in the outdoor unit wires of thermistor. thermistors (TH3, TH7, and TH8) and outdoor controller circuit board (TH3, TH7 and TH8) and branch branch box’s thermistors (TH-A~E)
Page 30 Abnormal point and detection method Judgment and action Error Code Case 1 Disconnection or loose 12 Check the installation conditions of (1) Too low superheat due to low dis- charge temperature connection of compressor compressor temperature thermistor (TH4). Abnormal if discharge superheat is contin- temperature thermistor.
Page 31 Abnormal point and detection method Judgment and action Error Code Case 1 Disconnection of compressor 1 Correct the wiring (U·V·W phase) to com- Current sensor error Abnormal if current sensor detects –1.5A wiring pressor. Refer to 8-7. 2 Defective circuit of current 2 Replace outdoor power circuit board.
Page 32 Abnormal point and detection method Judgment and action Error Code Case 1 Indoor–branch box/ 1 Check disconnection or looseness of indoor– Indoor - branch box/branch box - branch box–outdoor unit outdoor unit communication error branch box/branch box–outdoor unit connect- connecting wire has contact (Transmitting error) ing wire.
Page 33: Troubleshooting By Inferior Phenomena
8-4. TROUBLESHOOTING BY INFERIOR PHENOMENA Factor Phenomena Countermeasure 1 Refrigerant shortage 1 If refrigerant leaks, discharging tempera- 1. Remote controller display operates normally and the unit performs cool- ture rises and LEV opening increases. ing operation, however, the capacity Inspect leakage by checking the tem- cannot be fully obtained.
Page 34: Special Functions
8-5. SPECIAL FUNCTIONS 8-5-1. Low noise mode (on-site modification) (Fig. 8-1) By performing the following modification, operation noise of the outdoor unit can be reduced by about 3-4 dB. The low noise mode will be activated when a commercially available timer or the contact input of an ON/OFF switch is added to the CNDM connector (optional parts) on the control board of the outdoor unit.
Page 35 8-6. HOW TO CHECK THE PARTS MXZ-8B140VA MXZ-8B140YA MXZ-8B160VA MXZ-8B160YA Parts name Check points Disconnect the connector then measure the resistance with a tester. Thermistor (TH3) (At the ambient temperature 10 ~30 ) <Outdoor pipe> Normal Abnormal Thermistor (TH4) <Compressor>...
Page 36 Check method of DC fan motor (fan motor / outdoor controller circuit board) Notes · High voltage is applied to the connecter (CNF1, 2) for the fan motor. Pay attention to the service. · Do not pull out the connector (CNF1, 2) for the motor with the power supply on. board and fan motor.) (It causes trouble of the outdoor controller circuit Self check...
Page 37 <Thermistor feature chart> Low temperature thermistors Pipe temperature thermistor <Liquid> (TH3) Pipe temperature thermistor <Cond.> (TH6) Outdoor temperature thermistor (TH7) Gas pipe temperature thermistor (TH-A ~ TH-E)···· Branch box Thermistor R0 = 15k' ± 3% B constant = 3480 ± 2% =15exp{3480( 273+t –...
Page 38 8-7. TEST POINT DIAGRAM <CAUTION> TEST POINT 1 is high voltage. 8-7-1. Outdoor controller circuit board MXZ-8B140VA MXZ-8B140YA MXZ-8B160VA MXZ-8B160YA CNDM 1 to 2: Input of low-level sound priority mode CN51 1 to 3: Input of external contact point SW9 SW2...
Page 39 8-7-2. Outdoor noise filter circuit board MXZ-8B140YA MXZ-8B160YA LI1, LI2, LI3, NI POWER SUPPLY LI1-LI2/LI-LI3/LI3-LI1 : AC380/400/415V input LI1-NI/LI2-NI/LI3-NI : AC220/230/240V input (Connect to the terminal block (TB1)) Connect to the earth Connect to the earth CNAC1, CNAC2 AC220/230/240V (Connect to the outdoor controller circuit board (CNAC)) CNCT...
Page 40 8-7-3. Outdoor power circuit board MXZ-8B140VA MXZ-8B160VA Connect to the outdoor controller circuit board (CN2) 1-5: Transmitting signal to outdoor controller circuit board (0-5 V DC) Connect to the outdoor 2-5: Zero cross signal (0-5 V DC) controller circuit board (CN4)
Page 41 Brief Check of POWER MODULE W Usually, they are in a state of being short-circuited if they are broken. Outdoor power circuit board Measure the resistance in the following points (connectors, etc.). MXZ-8B140YA If they are short-circuited, it means that they are broken. MXZ-8B160YA 1.
Page 42 8-7-4. Outdoor converter circuit board MXZ-8B140YA MXZ-8B160YA L1-A1 L1-IN, N-IN CK-OU Connect to the ACL1 Connect to the noise filter Connect to the CK capacitor circuit board (LO1, No) Connect to the outdoor power circuit board (CN7) L1-A2, L2-A2, L3-A2 L1-OU, L2-OU, L3-OU Connect to the ACL1, ACL2, ACL3 Connect to the outdoor power circuit board...
Page 43 8-8. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS (1) Function of switches The black square (■) indicators a switch position. Action by the switch operation Type of Switch Function Effective timing Switch When compressor is Forced defrost Start Normal operating in heating operation.
Page 44 The black square (■) indicators a switch position. Action by the switch operation Type of Switch Function Effective timing Switch No function — — — Switching the target Target sub-cool down Normal Always sub-cool (Heating mode) — — — 3, 4 No function —...
Page 45 <Outdoor unit operation monitor function> Digital indicator LED3 displays 2 digit number or code to inform operation condition and the meaning of error code by controlling DIP SW2 on outdoor controller. Operation indicator SW2 : Indicator change of self diagnosis SW2 setting Display detail Explanation for display...
Page 46 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Pipe temperature / Liquid (TH3) – 40~90 – 40~90 (When the coil thermistor detects 0: or below, “–” and temperature are displayed by turns.) (Example) 2 3 4 5 6 When –10:;...
Page 47 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Pipe temperature / Liquid (TH3) on error – 40~90 occurring (When the coil thermistor detects 0: or below, “–” – 40~90 and temperature are displayed by turns.) (Example) When –15:;...
Page 48 Setting details Display details Defrosting switch 0 : Normal 1 : For high humidity (Example) MXZ-8B140VA, “00” is displayed. Indoor pipe temperature / Liquid – 39~88 – 39~88 (When the temperature is 0: or less, “–” and temperature are displayed by turns.)
Page 49 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Indoor setting temperature 17~30 17~30 Indoor unit 1 Indoor unit 2 Indoor unit 3 Indoor unit 4 2 3 4 5 6 Indoor unit 5 Indoor unit 6 Indoor unit 7...
Page 50 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Error postponement code history (2) Postponement code display of outdoor unit Blinking: During postponement Code Lighting: Cancellation of postponement display 2 3 4 5 6 “00”...
Page 51 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Indoor pipe temperature / Liquid on – 39~88 error occurring (When the temperature is 0 °C or less, “–” and – 39~88 temperature are displayed by turns.) Indoor unit 1 Indoor unit 2...
Page 52 ■ The black square ( ) indicates a switch position. SW2 setting Display detail Explanation for display Unit Thermostat-on time until error stops 0~999 0~999 (When it is 100 minutes or more, hundreds digit, tens digit and ones digit are displayed by turns.) (Example) When 415 minutes;...
Page 53 8-9. SELECTING FUNCTIONS USING THE REMOTE CONTROLLER Each function can be set according to necessity using the remote controller. The setting of function for each unit can only be done by the remote controller. Select function available from the table 1. (1) Functions available when setting the unit number to 00 W1 The functions table below are available only when P-series indoor unit and the wired remote controller is used.
Page 54: Electrical Wiring
ELECTRICAL WIRING 9-1. External wiring procedure (Fig. 9-1) E Power supply: 140/160V Single 220/230/240, 50 Hz 220V, 60Hz, 140/160Y 3-phase 380/440/415V, 50Hz Max. Permissive system Impedance : 0.22(") Note: 1 Power supply input: Outdoor unit only. Connect the lines (C), (D) in accordance with the terminal block names to ensure correct polarity.
Page 55 <Example 2> 9-2. Wiring to P100 indoor units (Fig. 9-2) (in case of wiring to P100 indoor unit(s)) • When wiring P100 indoor unit(s), only use PAC-AK52BC branch box. Branch Box • When wiring a single P100 indoor unit, use TB3A. (PAC-AK52BC only) Indoor unit TB3A...
Page 56: Wiring Specifications
WIRING SPECIFICATIONS Warning: In case of A-control wiring, there is high voltage potential on the S3 terminal caused by electrical circuit design that has no electrical insulation between power line and communication signal line. Therefore, please turn off the main power supply when servicing.
Page 57: System Control
SYSTEM CONTROL 11-1. BASIC SYSTEMS NOTE: The indoor units can be OC : Outdoor unit connected to any of the BC : Branch box 5 connectors IC : Indoor unit (5- branch type) or 3 connectors RC : Remote controller (3- branch type) of the branch box.
Page 58 11-3. INCORRECT SYSTEMS 11-3-1. Group operation by single remote controller BC (3- branch type) • Plural indoor units cannot be operated by a single remote controller. 11-3-2. Group operation between different refrigerant systems BC (3- branch type) BC (3- branch type) •...
Page 59: Refrigerant Piping Task
REFRIGERANT PIPING TASK 12-1. ADDITIONAL REFRIGERANT CHARGE a7 a8 Outdoor unit Branch box Indoor unit w1 Although two refrigerant pipes are used between the branch box and the Y-shape connection pipe when connecting the P100 indoor unit, calculate the piping lengths using only the length of one pipe.
Page 60 <Table 1> Total piping length 40m or less 41 – 50m 51 – 70m 71 – 90m 91 – 115m (b1+ b2 + a1+ a2 + a3 + a4 + a5 + a6 + a7 + a8) Additional refrigerant charging amount 0kg (no need) 0.6kg 1.4kg...
Page 61: Precautions Against Refrigerant Leakage
12-2. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE 12-2-1. Introduction (2) Calculate room volumes (m³) and find the room with the smallest volume R410A refrigerant of this air conditioner is non-toxic and non-flammable but leaking of large amount from an indoor The part with represents the room with the smallest unit into the room where the unit is installed may be deleteri- volume.
Page 62: Disassembly Procedure
DISASSEMBLY PROCEDURE MXZ-8B140VA MXZ-8B140YA MXZ-8B160VA MXZ-8B160YA OPERATING PROCEDURE PHOTOS & ILLUSTRATION 1. Removing the service panel and top panel Top panel fixing screws Top panel Photo 1 (1) Remove 3 service panel fixing screws (5 × 12) and slide the hook on the right downward to remove the service Service panel panel.
Page 63 OPERATING PROCEDURE PHOTOS 4. Removing the thermistor <Outdoor 2-phase pipe> (TH6) Photo 5 (1) Remove the service panel. (See Photo 1.) Thermistor Controller circuit board (2) Remove the top panel. (See Photo 1.) <Outdoor 2-phase pipe> (TH6) (C.B.) (3) Disconnect the connectors, TH6 and TH7 (red), on the controller circuit board in the electrical parts box.
Page 64 PHOTOS OPERATING PROCEDURE 7. Removing the solenoid valve coil <4-way valve> (21S4) Photo 8 (1) Remove the service panel. (See Photo 1.) (2) Remove the top panel. (See Photo 1.) [Removing the solenoid valve coil <4-way valve>] Solenoid valve coil <4-way valve>...
Page 65 PHOTOS OPERATING PROCEDURE 11. Removing the high pressure switch (63H) and low pres- Photo 10 sure switch (63L) (1) Remove the service panel. (See Photo 1.) High pressure switch (63H) Low pressure switch (63L) (2) Remove the top panel. (See Photo 1.) (3) Remove the electrical parts box.
Page 66 HEAD OFFICE : TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN cCopyright 2011 MITSUBISHI ELECTRIC ENGINEERING CO., LTD. Distributed in Sep. 2011 No.OCH480 REVISED EDITION-A Distributed in Jul. 2011 No.OCH480 New publication, effective Sep. 2011 Made in Japan Specifications subject to change without notice.

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