Mitsubishi Electric MXZ-8B48NA Technical & Service Manual
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Mitsubishi Electric MXZ-8B48NA Technical & Service Manual

Hfc utilized r410a, split-type, heat pump air conditioners, outdoor unit, branch box
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SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
TECHNICAL & SERVICE MANUAL
[Model name]
MXZ-8B48NA
PAC-AKA51BC
PAC-AKA31BC
(Indispensable optional parts
for MXZ-8B48NA)
OUTDOOR UNIT
BRANCH BOX
[Service Ref.]
MXZ-8B48NA
MXZ-8B48NAR1
PAC-AKA51BC
PAC-AKA31BC
CONTENTS
1. TECHNICAL CHANGE .................................... 2
2. SAFETY PRECAUTION .................................... 2
3. OVERVIEW OF UNITS ...................................... 5
4. SPECIFICATIONS ............................................. 9
5. DATA ................................................................ 11
6. OUTLINES AND DIMENSIONS ...................... 34
7. WIRING DIAGRAM ......................................... 36
9. TROUBLESHOOTING .................................... 39
Model name
indication
11. DISASSEMBLY PROCEDURE ....................... 81
REVISED EDITION-C
Revision:
• Switch setting on page 68
has been modified in
REVISED EDITION-C.
• Some descriptions have
been modified.
• Please void OCH468
REVISED EDITION-B.
NOTE:
• This service manual
describes technical data of
outdoor unit and branch box.
As for indoor units, refer to
its service manual.
• RoHS compliant products
have mark on the spec
name plate.
PARTS CATALOG (OCB468)
November 2010
No. OCH468
HFC
utilized
R410A
Table of Contents
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Summary of Contents for Mitsubishi Electric MXZ-8B48NA

  • Page 1 As for indoor units, refer to PAC-AKA31BC its service manual. • RoHS compliant products (Indispensable optional parts have mark on the spec for MXZ-8B48NA) name plate. CONTENTS 1. TECHNICAL CHANGE ........2 2. SAFETY PRECAUTION ........2 3. OVERVIEW OF UNITS ........5 4.

  • Page 2: Technical Change

    TECHNICAL CHANGE MXZ-8B48NA MXZ-8B48NAR1 • THERMISTOR has been changed. (Discharge thermistor Compressor thermistor) SAFETY PRECAUTION 2-1. ALWAYS OBSERVE FOR SAFETY Before obtaining access to terminal, all supply circuit must be disconnected. 2-2. CAUTIONS RELATED TO NEW REFRIGERANT Cautions for units utilizing refrigerant R410A Use new refrigerant pipes.
  • 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 2-3. 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 3-1. CONSTRUCTION OF SYSTEM MXZ-8B48NA, MXZ-8B48NAR1 Rated capacity (kBTU/h) 48/54 (Cooling/Heating) MAX. capacity (kBTU/h) Outdoor unit 54/60 (Cooling/Heating) R410A Indoor unit Type 06 ~ Type 24 Capacity that can be connected Number of units 2 ~ 8 units Total system wide capacity 22.2 ~ 130 % of outdoor unit MAX.
  • Page 6 3-2. SYSTEM OUTLINE The additional connection of the Branch Box together with employment of the compact trunk-looking outdoor unit can suc- cessfully realizes a long distance piping for big houses. Equipped with a microcomputer, the Branch Box can translate the transmission signal of indoor units to achieve the optimum control.
  • Page 7 3-3. 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 Bedroom (1)
  • Page 8 3-4. SIMPLIFIED PIPING SYSTEM Piping connection size The piping connection size differs according to the type and capacity of indoor units. 9.52 mm Liquid Match the piping connection size of branch box with indoor unit. (3/8 inch) If the piping connection size of branch box does not match the piping connection size of 15.88 mm indoor unit, use optional different-diameter (deformed) joints to the branch box side.

  • Page 9: Specifications

    L (oz) 2.3 (73) / FV50S Protection devices High pressure protection HP switch Compressor protection Discharge thermo, Over current detection (MXZ-8B48NA) Compressor thermo, Over current detection (MXZ-8B48NAR1) Fan motor protection Overheating / Voltage protection Guaranteed operation range (cool) -5 ∼ 46 °C DB (23 ~ 115 °F DB) (heat) -15 ∼...
  • Page 10 • Branch box : PAC-AKA51BC PAC-AKA31BC PAC-AKA51BC PAC-AKA31BC Model name MAX. 3 Connectable number of indoor units MAX. 5 Single phase, 208/230V, 60Hz Power supply (from outdoor unit) 0.003 Input Running current 0.05 Galvanized sheets External finish O.D.20 (O.D. 3/4) Drain hose size (on site) mm (in.) 450 (17 - 3/4)

  • Page 11: Data

    DATA 5-1. CAPACITY AND CHARACTERISTICS Note: • Cooling capacity is based on D.B. 26.7 °C / W.B. 19.4 °C (D.B. 80 °F / W.B. 67 °F) (indoor temperature), D.B. 35 °C (D.B. 95 °F) (outdoor temperature). • Heating capacity is based on D.B. 21.1 °C (D.B. 70 °F) (indoor temperature), D.B. 8.3 °C / W.B. 6.1 °C (D.B. 47 °F / W.B. 43 °F) (outdoor temperature).
  • Page 12 Indoor unit combinations Capacity of each unit (BTU/h) Total rated Outdoor Outdoor unit current (A) capacity unit input Unit A Unit B Unit C Unit D Unit A Unit B Unit C Unit D 208V 230V (BTU/h) 9000 9000 9000 27000 2540...
  • Page 13 Indoor unit combinations Capacity of each unit (BTU/h) Total rated Outdoor Outdoor unit current (A) capacity unit input Unit A Unit B Unit C Unit D Unit A Unit B Unit C Unit D 208V 230V (BTU/h) 6000 9000 9000 9000 33000...
  • Page 14 Outdoor unit Total rated Outdoor Indoor unit combinations Capacity of each unit (BTU/h) current (A) capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit A Unit B Unit C Unit D Unit E 208V 230V 7040...
  • Page 15 Outdoor unit Total rated Outdoor Indoor unit combinations Capacity of each unit (BTU/h) current (A) capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit A Unit B Unit C Unit D Unit E 208V 230V 5680...
  • Page 16 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F 208V 230V 4910 9820 9820 14730 14730 54010 3930 19.2...
  • Page 17 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F 208V 230V 5680 5680 5680 5680 8530 22740 53990 4940...
  • Page 18 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F Unit G 208V 230V 5400 5400 10800 10800 10800 10800...
  • Page 19 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit Input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F Unit G 208V 230V 5140 5140 5140 5140 5140 7710...
  • Page 20 Indoor unit combinations Total Outdoor Outdoor unit Capacity of each unit (BTU/h) rated unit current (A) Unit capacity Input Unit A Unit B Unit C Unit D Unit E Unit F Unit G Unit H 208V 230V (BTU/h) 06 09 09 09 09 09 18 4700 7040 7040...
  • Page 21 (2) Heating mode Indoor unit combinations Capacity of each unit (BTU/h) Total rated Outdoor Outdoor unit current (A) capacity unit input Unit A Unit B Unit C Unit A Unit B Unit C 208V 230V (BTU/h) 7200 7200 10900 10900 1100 14400...
  • Page 22 Indoor unit combinations Capacity of each unit (BTU/h) Total rated Outdoor Outdoor unit current (A) capacity unit input Unit A Unit B Unit C Unit D Unit A Unit B Unit C Unit D 208V 230V (BTU/h) 10900 10900 10900 32700 3390...
  • Page 23 Indoor unit combinations Capacity of each unit (BTU/h) Total rated Outdoor Outdoor unit current (A) capacity unit input Unit A Unit B Unit C Unit D Unit A Unit B Unit C Unit D 208V 230V (BTU/h) 7200 10900 10900 10900 39900...
  • Page 24 Outdoor unit Total rated Outdoor Indoor unit combinations Capacity of each unit (BTU/h) current (A) capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit A Unit B Unit C Unit D Unit E 208V 230V 7890...
  • Page 25 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E 208V 230V 6310 6310 9550 12610 25230 60010 4610 22.5 20.4 7050...
  • Page 26 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F 208V 230V 5450 10910 10910 16360 16360 59990 4010 19.6...
  • Page 27 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F 208V 230V 6310 6310 6310 6310 9550 25230 60020 4610...
  • Page 28 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F Unit G 208V 230V 6000 6000 12000 12000 12000 12000...
  • Page 29 Indoor unit combinations Outdoor unit Total rated Outdoor Capacity of each unit (BTU/h) current (A) Unit capacity unit input (BTU/h) Unit A Unit B Unit C Unit D Unit E Unit F Unit G 208V 230V 5710 5710 5710 5710 5710 8640...
  • Page 30 Indoor unit combinations Total Outdoor Outdoor unit Capacity of each unit (BTU/h) rated unit current (A) Unit capacity Input Unit A Unit B Unit C Unit D Unit E Unit F Unit G Unit H 208V 230V (BTU/h) 06 09 09 09 09 09 18 5190 7850 7850...
  • Page 31 5-2. CORRECTING COOLING AND HEATING CAPACITY 5-2-1. Correcting Changes in Air Conditions (1)The performance curve charts (Figure 1-1, 1-2, 2-1, 2-2) 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 32 5-2-2. Correcting Capacity for Changes in the Length of Refrigerant Piping To obtain the ratio (and the corrected piping length) of the outdoor units Max. capacity and the total in-use indoor capacity, first find the capacity ratio corresponding to the standard piping length from Fig.3, Fig.4 and then multiply by the capacity from Fig. 1-1, 1-2, Fig.
  • Page 33 5-3. NOISE CRITERION CURVES MICROPHONE 1m(3.3ft) UNIT 1.5m (5ft) GROUND MXZ-8B48NA SPL(dB) MODE LINE COOLING MXZ-8B48NAR1 HEATING NC-70 NC-60 NC-50 NC-40 NC-30 APPROXIMATE THRESHOLD OF HEARING FOR NC-20 CONTINUOUS NOISE 1000 2000 4000 8000 BAND CENTER FREQUENCIES, Hz...

  • Page 34: Outlines And Dimensions

    OUTLINES AND DIMENSIONS 6-1. OUTDOOR UNIT unit : mm (inch) MXZ-8B48NA MXZ-8B48NAR1...
  • Page 35 6-2. BRANCH BOX UNIT unit : mm (inch) PAC-AKA51BC SUSPENSION BOLT PITCH 320 <12-5/8> SUSPENSION BOLT : W3/8(M10) REFRIGERANT PIPE FLARED CONNECTION When installing the conduit. TO OUT DOOR UNIT Set the attachment to the LIQUID PIPE 1/4F 1/4F 1/4F 1/4F 1/4F 3/8F...

  • Page 36: Wiring Diagram

    WIRING DIAGRAM 7-1. OUTDOOR UNIT MXZ-8B48NA MXZ-8B48NAR1...
  • Page 37 7-2. BRANCH BOX : PAC-AKA51BC PAC-AKA31BC Setup of SW1 Make it the same setup as former when exchanging PCB. The black square ( ) indicates a switch position.

  • Page 38: Necessary Conditions For System Construction

    Capillary tube 3 Capillary tube 2 behind LEV (For return of oil ahead of LEV (For SV2) (in cooling mode) from oil separator) (in cooling mode) Outdoor unit MXZ-8B48NA L1000 L250 ( 0.098 0.031 L(39-1/2)) ( 0.157 0.094 L10) MXZ-8B48NAR1...

  • Page 39: Troubleshooting

    TROUBLESHOOTING 9-1. TROUBLESHOOTING 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 40 9-2. CHECK POINTS FOR TEST RUN 9-2-1. 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. After completing installation and the wiring and piping of the indoor and outdoor units, check for refrigerant leakage, loose- ness in the power supply or control wiring, wrong polarity, and no disconnection of one phase in the supply.
  • Page 41 (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 42 9-3. SELF-DIAGNOSIS ACTION TABLE (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 43 Error Code Abnormal point and detection method Case Judgment and action 1 Contact failure or miswiring of 1 Check disconnection or looseness or polar- Indoor–branch box/branch box–outdoor indoor/outdoor unit connecting ity of indoor –branch box/branch box–outdoor unit connector miswiring, excessive unit connecting wire of indoor and outdoor wire number of units...
  • Page 44 Abnormal point and detection method Judgment and action Error Code Case (1) High-pressure switch (63H) operated 1) Short cycle of indoor unit 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 45 Abnormal point and detection method Case Judgment and action Error Code 1 Overheated compressor opera- 1 Check intake superheat. (1) High discharging/compressor temperature Abnormal if discharge/compressor tion caused by shortage of Check leakage of refrigerant. temperature thermistor (TH4) exceeds refrigerant Charge additional refrigerant.
  • Page 46 Abnormal point and detection method Judgment and action Error Code Case 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 47 Abnormal point and detection method Judgment and action Error Code Case 1 Disconnection or loose 12 Check the installation conditions of dis- (1) Too low superheat due to low dis- charge/compressor temperature connection of discharge/com- charge/compressor temperature thermistor Abnormal if discharge superheat is con- pressor temperature thermistor.
  • Page 48 Abnormal point and detection method Judgment and action Error Code Case 1 Stop valve of outdoor unit is 1 Check stop valve. Low pressure (63L operated) Abnormal if 63L is operated (under closed during operation. 2 Disconnection or loose con- 2~4 Turn the power off and on again to check –0.03MPa [–4.35PSIG]) during compres- sor operation.
  • Page 49 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 - outdoor unit communication error branch box–outdoor unit con- branch box/branch box–outdoor unit connect- necting wire has contact failure.
  • Page 50 9-4. TROUBLESHOOTING BY INFERIOR PHENOMENA Factor Phenomena Countermeasure 1Refrigerant shortage 1 If refrigerant leaks, discharging tempera- 1. Remote controller display works 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 51: Special Functions

    9-5. SPECIAL FUNCTIONS 9-5-1. Low noise mode (on-site modification) (Fig. 9-1) 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 52 9-6. HOW TO CHECK THE PARTS OUTDOOR UNIT : MXZ-8B48NA MXZ-8B48NAR1 Parts name Check points Disconnect the connector then measure the resistance with a tester. Thermistor (TH3) (At the ambient temperature 10 ~30 , 50°F~86°F) Normal Abnormal Thermistor (TH4) ...
  • Page 53 Check method of DC fan motor (fan motor / outdoor controller circuit board) Notes · High voltage is applied to the connector (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 54 Vout (V) OUTDOOR CONTROLLER BOARD 5V DC Vout MICRO PROCESSOR 63HS : 5V (DC) : Output Vout (DC) PSIG PRESSURE Low temperature thermistors • Thermistor (TH3) • Thermistor <2-phase pipe> (TH6) • Thermistor (TH7) •...
  • Page 55 BRANCH BOX : PAC-AKA51BC PAC-AKA31BC Parts name Check points Disconnect the connector then measure the resistance with a tester. Thermistor (TH-A~E) (At the ambient temperature 10 ~30 , 50°F~86°F) Normal Abnormal 4.3k ~9.6k Open or short Disconnect the connector then measure the resistance with a tester. Linear expansion valve (Winding temperature 20 , 68°F) ( LEV-A~E )
  • Page 56 Linear expansion valve (LEV) in Branch box (1) Operation summary of the linear expansion valve • Linear expansion valve open/close through stepping motor after receiving the pulse signal from the branch box controller board. • Valve position can be changed in proportion to the number of pulse signal. ...
  • Page 57 (3) How to attach and detach the coil of linear expansion valve Linear expansion valve is separable into the main body and the coil as shown in the diagram below. Main body Coil Lead wire Stopper Hold the lower part of the main body (shown as A) firmly so that the main body does not move and detach the coil by pulling it upward.
  • Page 58 Troubleshooting Check point Corrective measure Problem Locked expansion Replace the linear If the linear expansion valve becomes locked and the motor is still operating, valve expansion valve. the motor will emit a clicking noise and will not function. This clicking noise indicates an abnormality.
  • Page 59 9-7. TEST POINT DIAGRAM TEST POINT1 is high voltage. Outdoor controller circuit board MXZ-8B48NA SW9 SW2 Forced defrost, detect history record reset CN3S MXZ-8B48NAR1 CN51 CNDM 1 to 2: Input of low noise Model select mode 1 to 3:...
  • Page 60 Outdoor power circuit board MXZ-8B48NA MXZ-8B48NAR1 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 61 Branch box controller board PAC-AKA51BC LED1 PAC-AKA31BC Transmission start-up state display TH-A to E Connect to LEV-A to E Start-up : LED1 blinks Thermistor-A to E (0.5sec. : ON, 0.5sec. : OFF) Connect to LEV-A to E TH-A to C for PAC-AKA31BC LEV-A to C for PAC-AKA31BC Start-up completion: LED1 lights LED3~5...
  • Page 62 9-8. FUNCTION OF SWITCHES, CONNECTORS AND JUMPERS (1) Function of switches MXZ-8B48NA MXZ-8B48NAR1 The black square ( ) indicates a switch position. Type of Action by the switch operation Switch Function Effective timing Switch When compressor is Forced defrost Start...
  • Page 63 MXZ-8B48NA MXZ-8B48NAR1 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) No function — — — 3, 4 No function —...
  • Page 64 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 65 Explanation for display SW2 setting Display detail Unit Pipe temperature / Liquid (TH3) – 40~194 – 40~194 (When the coil thermistor detects 0°F or below, “–” and temperature are displayed by turns.) °F (Example) 2 3 4 5 6 When –10°F; 0.5 secs.
  • Page 66 Display detail Explanation for display Unit SW2 setting Pipe temperature / Liquid (TH3) on error – 40~194 occurring (When the coil thermistor detects 0°F or below, “–” – 40~194 and temperature are displayed by turns.) °F (Example) When –15°F; 0.5 secs. 0.5secs.
  • Page 67 Setting details Display details Defrosting switch 0 : Normal 1 : For high humidity (Example) MXZ-8B48NA, “00” is displayed. Indoor pipe temperature / Liquid – 38~190 – 38~190 (When the temperature is 0°F or less, “–” and temperature are displayed by turns.)
  • Page 68 Display detail Explanation for display Unit SW2 setting Indoor setting temperature 62~86 62~86 Indoor unit 1 Indoor unit 2 °F Indoor unit 3 Indoor unit 4 2 3 4 5 6 Indoor unit 5 Indoor unit 6 Indoor unit 7 Indoor unit 8 Outdoor pipe temperature / 2-phase –...
  • Page 69 Display detail Explanation for display Unit SW2 setting Target Sub-cool (Cooling mode) : SCm 0~255 2 3 4 5 6 Error postponement code history (2) Postponement code display of outdoor unit Blinking: During postponement Code Lighting: Cancellation of postponement display “00”...
  • Page 70 Display detail Explanation for display Unit SW2 setting 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 (Example) Indoor unit 2 Indoor unit 3 When –15°C;...
  • Page 71 SW2 setting Display detail Explanation for display Unit Thermo 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; Minute 0.5 secs. 0.5secs.
  • Page 72 [When option part ‘A-Control Service Tool (PAC-SK52ST)’ is connected to branch box controller board (CNM)] Digital indicator LED1 displays 2 digit number or code to inform operation condition and the meaning of error code by controlling DIP SW2 on ‘A-Control Service Tool’.
  • Page 73 Display detail Explanation for display Unit SW2 setting LEV-B opening pulse 0~500 0~500 (When it is 100 pulse or more, hundreds digit, tens digit and ones digit are displayed by turns. Pulse (Example) 2 3 4 5 6 When 150 pulse; 0.5 secs. 0.5secs.
  • Page 74 Display detail Explanation for display SW2 setting Unit Indoor pipe temperature / Liquid – 35~88 (°C), – 31~190 (°F) (When the temperature is 0: or less, “–” and °C Indoor-B temperature are displayed by turns.) °F(w) – 35~88 (°C) 2 3 4 5 6 –...
  • Page 75 Display detail Explanation for display Unit SW2 setting Outdoor heatsink temperature (TH8) – 40~200 (°C), – 40~327 (°F) – 40~200 (°C) (When the temperature is 0: or less, “–” and – 40~327 (°F)w temperature are displayed by turns.) °C (When the thermistor detects 100: or more, °F 2 3 4 5 6 hundreds digit, tens digit and ones digit are...
  • Page 76 Display detail Explanation for display Unit SW2 setting Branch pipe temperature – 39~88 (°C) TH-A – 38~190 (°F)w °C °F(w) 2 3 4 5 6 Branch pipe temperature – 39~88 (°C) TH-B – 38~190 (°F)w °C °F(w) 2 3 4 5 6 Branch pipe temperature –...
  • Page 77 SW2 setting Display detail Explanation for display Unit Indoor - setting temperature 16~31 (°C) Indoor-A 60~87 (°F)w °C °F(w) 2 3 4 5 6 Indoor - setting temperature 16~31 (°C) Indoor-B 60~87 (°F)w °C °F(w) 2 3 4 5 6 Indoor - setting temperature 16~31 (°C) Indoor-C...
  • Page 78 9-9. 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 79: Precautions Against Refrigerant Leakage

    PRECAUTIONS AGAINST REFRIGERANT LEAKAGE The installer and system specialist shall secure safety against leakage according to local regulations or standards. The following standards may be applicable if local regulations are not available. 10-1. INTRODUCTION R410A refrigerant of this air conditioner is non-toxic and non-flammable but leaking of large amount from an indoor unit into the room where the unit is installed may be deleterious.
  • Page 80 (b) There are partitions, but there are openings that allow the effective mixing of air. Outdoor unit (Situation in which there are no door openings or Indoor unit in which there are openings above and blow doors that occupy at least 0.15% of the floor area) Opening Wall (c) If the smallest room has mechanical ventilation...

  • Page 81: Disassembly Procedure

    DISASSEMBLY PROCEDURE OUTDOOR UNIT : MXZ-8B48NA MXZ-8B48NAR1 OPERATING PROCEDURE PHOTOS & ILLUSTRATION Top panel fixing screws Top panel Figure 1 1. Removing the service panel and top panel (1) Remove 3 service panel fixing screws (5 × 12) and slide...
  • Page 82 OPERATING PROCEDURE PHOTOS 4. Removing the thermistor (TH6) Photo 4 Thermistor (1) Remove the service panel. (See Figure 1) (TH6) (2) Remove the top panel. (See Figure 1) Controller circuit board (C.B.) (3) Disconnect the connectors, TH6 and TH7 (red), on the controller circuit board in the electrical parts box.
  • Page 83 OPERATING PROCEDURE PHOTOS Photo 7 7. Removing the solenoid valve coil <4-way valve> (21S4) (1) Remove the service panel. (See Figure 1) (2) Remove the top panel. (See Figure 1) [Removing the solenoid valve coil <4-way valve>] Solenoid valve coil (3) Remove 4-way valve solenoid coil fixing screw (M4 ×...
  • Page 84 OPERATING PROCEDURE PHOTOS 11. Removing the high pressure switch (63H) and Photo 9 low pressure switch (63L) (1) Remove the service panel. (See Figure 1) High pressure switch (63H) Low pressure switch (63L) (2) Remove the top panel. (See Figure 1) (3) Remove the electrical parts box.
  • Page 85 BRANCH BOX : PAC-AKA51BC PAC-AKA31BC PHOTO : PAC-AKA51BC OPERATING PROCEDURE PHOTOS 1. Removing the controller cover and under panel Photo 1 (1) Remove 3 controller cover fixing screws (4 o 10) to detach Under panel fixing screws the cover. (See Photo 1) (2) Remove 6 under panel fixing screws (4 o 10) to remove the panel.
  • Page 86 OPERATING PROCEDURE PHOTOS 4. Removing the LEV coil (LEV-A–E) Photo 4 (1) Remove the controller cover. (See Photo 1) Separator fixing screws (2) Remove the under cover. (See Photo 1) (3) Remove 4 separator fixing screws (4 o 10) in the side of the branch box.
  • Page 88 HEAD OFFICE : TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN cCopyright 2010 MITSUBISHI ELECTRIC ENGINEERING CO., LTD. Distributed in Nov. 2010 No. OCH468 REVISED EDITION-C Distributed in Sep. 2010 No. OCH468 REVISED EDITION-B PDF 5 New publication, effective Nov. 2010 Distributed in Jun.

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Mxz-8b48nar1Pac-aka31bcPac-aka51bc

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