Mitsubishi Electric PAC-MK34BC Technical & Service Manual Download Page 25

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OPERATING PROCEDURE

PHOTOS/FIGURES

Removing the LEV coil (LEV-A–E*)

(1) Remove the controller cover. (See Photo 1)

(2) Remove the under cover. (See Photo 1)

(3) Remove 8 insulations, then remove 9 pipe cover fixing

screws (4 x 10). (See Photo 2-1)

(4) Cut the bands that fixes the lead wire, then pull out the

LEV coil(s) (LEV-A –E*). (See Photo 3)

(5) Loosen the insulation sheet which bundles the LEV lead

wires.

(6) Loosen the side clamps, then disconnect the connector(s)

on the controller board.

(7) Pull out the lead wire(s) through the hole to the controller

board side.

(See Photo 2-2 or 2-3)

*LEV-A–C for PAC-MK34BC (See Photo 2-3)

Photo 3

Removing the controller board

(1) Remove the controller cover. (See Photo 1)

(2) Loosen the side clamps, then disconnect the connectors

on the controller board.

(3) Pick an upper edge of the controller board, then pull for

ward. The controller board is fixed to the controller board

holder with 4 hooks. (See Photo 4)

(4) Remove the controller board from the controller board

holder.

Photo 4

LEV coils

Bands

Hooks

Controller board holder

Header assy

LEV assy

Rubber mount

Controller board

Insulation sheet

OCH744

Summary of Contents for PAC-MK34BC

Page 1: ...GRAM 10 6 NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION 11 7 TROUBLESHOOTING 15 8 DISASSEMBLY PROCEDURE 24 BRANCH BOX HFC utilized R410A Note This service manual describes technical data of branch box As for indoor units and outdoor unit refer to its service manual PARTS CATALOG OCB744 PAC MK54BC No OCH744 Service Ref PAC MK54BC PAC MK34BC Model Name Branch box PAC MK54BC PAC MK34BC ...

Page 2: ... rant piping is clean and it has no contaminants such as sulfur oxides dirt shaving particles etc which are hazard to refrigerant cycle In addition use pipes with specified thickness Contamination inside refrigerant piping can cause deterio ration of refrigerant oil etc Store the piping indoors and keep both ends of the piping sealed until just before brazing Leave elbow joints etc in their packag...

Page 3: ...air 3 After completing service charge the cycle with specified amount of refrigerant 4 If moisture or foreign matter might have entered the refrigerant piping during service ensure to remove them No Tool name Specifications 1 Gauge manifold Only for R410A Use the existing fitting specifications UNF1 2 Use high tension side pressure of 5 3MPa G or over 2 Charge hose Only for R410A Use pressure perf...

Page 4: ...22 0 26 0 29 0 17 0 22 0 24 0 27 0 36 0 Nominal dimensions in Flare nut dimensions Outside diameter mm Dimension B mm R410A R22 Gauge manifold Charge hose Gas leak detector Refrigerant recovery equipment Refrigerant cylinder Applied oil Safety charger Charge valve Vacuum pump Flare tool Bender Pipe cutter Welder and nitrogen gas cylinder Refrigerant charging scale Vacuum gauge or thermis tor vacuu...

Page 5: ...ox can translate the transmission signal of indoor units to achieve the optimum control 2 1 1 System example 2 1 2 Method for identifying Branch box Controller Number of branches 5 5 branches 3 3 branches Model type Model type P A C MK 5 4 BC Indispensable Optional parts Development No A B etc Power supply Single phase 220 230 240 V 50 Hz Multi type heat pump inverter outdoor unit Indicates equiva...

Page 6: ...ils and sensors is possible To install the optional reactor box set A to Min 270 mm recommendation Fig 2 4 3 B is 600 mm In the case of 450 mm prepare a maintenance hole at a PCB side as it is shown in Fig 2 3 Fig 2 4 and Min 300 mm is needed as distance A In the case of less than 300 mm for example A is 100 mm the exchange work of Branch box linear expansion valve coils and sensors from a mainten...

Page 7: ...f MSDD 50AR E and MSDD 50BR E 2 3 SIMPLIFIED PIPING SYSTEM The piping connection size differs according to the type and capacity of outdoor indoor units Match the piping connection size of branch box with outdoor indoor unit If the piping connection size of branch box does not match the piping connection size of outdoor indoor unit use optional different diameter deformed joints to the branch box ...

Page 8: ... Branch indoor side Liquid mm ø6 35 5 A B C D E ø6 35 3 A B C Gas mm ø9 52 4 A B C D ø12 7 1 E ø9 52 3 A B C Main outdoor side Liquid mm ø9 52 Gas mm ø15 88 The piping connection size differs according to the type and capacity of outdoor indoor units Match the piping connection size of branch box with outdoor indoor unit If the piping connection size of branch box does not match the piping connect...

Page 9: ... UNIT 40 280 83 96 112 70 87 TERMINAL BLOCK TO M NET UNIT TERMINAL BLOCK TO INDOOR UNIT TERMINAL BLOCK TO OUTDOOR UNIT TB2B TB5 TB3E TB3C TB3A TB3D TB3B 24 CAP CAP C B C B A A TO INDOOR UNIT 450 70 70 25 65 47 170 209 25 25 90 72 5 ELECTRIC WIRE INLET BUSH CONTROL COVER TO OUTDOOR UNIT SERVICE PANEL for LEV THERMISTOR 83 96 40 280 87 70 112 TB3A TB3C TB3B TB5 TB2B TERMINAL BLOCK TO OUTDOOR UNIT TE...

Page 10: ...D and E for PAC MK54BC only start up Mark LED 1 LED 2 Main power supply Meaning Main power supply 220 230 240V Power on Lamps are lit Function Mark LED 2 Total number of indoor units Meaning Blink depend on the total number example The total number is 2 1 Blink 2 times 2 Turn off for 3 sec 3 Repeat 1 to 2 LED 1 Main power supply Lamp is lit Function normal operating PAC MK 54BC only BU BU BK WH RD...

Page 11: ...s SW 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 Address SW SW1 ON 1 2 3 4 5 6 SW1 ON 1 2 3 4 5 6 CITY MULTI Indoor unit 009 CITY MULTI Indoor unit 010 MA remote controller CITY MULTI 001 050 For centralized management 061 Outdoor unit For Branch box CITY MULTI indoor unit 0 1 2 3 4 5 6 7 8 9 Address SW CITY MULTI Indoor unit 011 CITY MULTI Indoor unit 012 CITY MULTI Indoor unit 013 CITY MULTI Indoor ...

Page 12: ...re LEV A E Linear expansion valve C B A Strainer 100 Strainer 100 Thermistor TH A C Gas pipe temperature LEV A C Linear expansion valve PAC MK54BC PAC MK34BC Branch box Capillary tube behind LEV in cooling mode ø4 o ø3 0 o L130 o 5 ø4 o ø3 0 o L130 o 3 Unit mm PAC MK54BC PAC MK34BC 6 2 REFRIGERANT SYSTEM DIAGRAM ...

Page 13: ...th the system controller 2 Timer operation 1 Timer operation should be set using only 1 controller from the remote controller that comes with the room air conditioner the system controller or the MA remote controller If more than 1 controller is used to set the timer at the same time the timer will not function properly 2 When the timer is set with the wireless remote controller the system control...

Page 14: ... be used DIDO controller Interlock with the air conditioner Fan control of energy saving control or peak cut control function Air conditioning charge TG 2000A Set temperature range limiting function Operation mode changeover limit season changing PAC SF44SRA Dual set point function Cylinder unit or hydrobox cannot be operated from system controller ...

Page 15: ... E 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Orange Red White 1 2 3 4 5 M Blue Yellow Oran...

Page 16: ...ound can be heard No sound is heard when the pulse number moves from B to A in case coil is burnt out or motor is locked by open phase Sound can be detected by placing the ear against the screw driver handle while putting the screw driver to the linear expansion valve Linear expansion valve 1 Operation summary of the linear expansion valve Linear expansion valve opens closes through stepping motor...

Page 17: ...ss Be sure to attach the stopper to pipe B B A How to attach the coil Hold the lower part of the main body shown as A firmly so that the main body does not move and attach the coil by inserting it downward into the main body Then securely attach the coil stop per to pipe B At this time be careful that stress is not added to lead wire and main body is not wound by lead wire If the stopper is not fi...

Page 18: ...ve should be fully closed when the fan is operating The temperature measured by the temperature sensor will drop if there is any leakage If the measured temperature is significantly lower than that on the remote controller this indicates that the valve is not closed It is not necessary to replace the linear expansion valve if the leak of refrigerant is small and does not cause a malfunction 1 Chec...

Page 19: ...C non polar TB3A to E Connect to indoor unit TB3D and TB3E for PAC MK54BC only 1 3 Power supply 3 5 Transmission 2 4 220 230 240 VAC 4 6 0 24 VDC LED1 LED2 Startup Main power supply 220 230 240 VAC Normal operating LED1 Main power supply LED2 Blink depend on the total number of indoor units Example The total number is 2 1Blink 2 times 2Turn OFF for 3 seconds 3Repeat 1 2 TH A to E Connect to thermi...

Page 20: ...ve 5 System type Cooling only system Cooling heating system When the outdoor unit is cooling only system turn SW4 5 to ON 6 7 Model setting Refer to Initial switch setting 8 10 SW5 Service setting 1 3 Change INDOOR UNIT No for monitoring Refer to 7 4 BRANCH BOX UNIT OPERATION MONITOR FUNCTION Can be activated at any time 4 6 When the cylinder unit or hydrobox is used in a house connect the indoor ...

Page 21: ...SW5 Use to set the displayed unit SW2 setting Display detail Explanation for display Unit SW5 setting 1 Common Status of branch box During startup 0 5 s 0 5 s During error detection Displays a check code and M NET address of the unit which the check code was detected Example If the check code 2520 is detected in the address3 0 5 s 0 5 s 0 5 s 2 0 s 25 03 20 During no power supply F8 Other Displays...

Page 22: ...se 1 ON 2 3 4 5 6 Common Not used Individual unit Error history Code display 25 03 20 Common The number of unit s operating in Thermo ON Number Individual unit Operating status of unit Code display Common The number of indoor unit s connected to this branch box 0 to 5 Number Individual unit M NET address 00 to FF M NET address of the selected unit M NET address is displayed in hexadecimal Display ...

Page 23: ...ample If it is a ver 12 34 0 5 s 0 5 s 2 0 s Pulse Common Branch Box Software ROM check sum Individual unit 8 to 39 C9 0b Indoor thermistor pipe temperature 2 phase TH5 39 to 88 When the temperature is 0 C or less and temperature are displayed by turns Example When 5 C 0 5 s 0 5 s 2 0 s C 5 42 to 91 When the temperature is 0 C or less and temperature are displayed by turns Example When 5 C 0 5 s 0...

Page 24: ...oto 2 2 5 Loosen the insulation sheet which bundles the thermistor connectors 6 Loosen the side clamps then disconnect the connector s on the controller board 7 Pull out the lead wire s through the hole to the controller board side TH A C for PAC MK34BC See Photo 2 3 Photo 2 1 Photo 2 2 Photo 2 3 Controller cover fixing screws Controller cover fixing screw Under panel fixing screws Insulations 15 ...

Page 25: ...ller board 7 Pull out the lead wire s through the hole to the controller board side See Photo 2 2 or 2 3 LEV A C for PAC MK34BC See Photo 2 3 Photo 3 4 Removing the controller board 1 Remove the controller cover See Photo 1 2 Loosen the side clamps then disconnect the connectors on the controller board 3 Pick an upper edge of the controller board then pull for ward The controller board is fixed to...

Page 26: ...sembling the pipe box 8 Remove 2 side panel fixing screws 4 x 10 See Photo 5 1 9 Pull out the pipe box top and separate it from the side panel See Photo 5 2 10 Turn the pipe box top upside down See Photo 5 3 11 Remove 5 insulations then remove 5 pipe box top fixing screws 4 x 10 12 Turn the pipe box top upside down again facing the pipe side up 13 Separate the pipe box center from the pipe box top...

Page 27: ...27 OCH744 ...

Page 28: ...ht 2020 MITSUBISHI ELECTRIC CORPORATION Published May 2020 No OCH744 Made in Japan Specifications are subject to change without notice HEAD OFFICE TOKYO BUILDING 2 7 3 MARUNOUCHI CHIYODA KU TOKYO100 8310 JAPAN ...

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