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SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS
TECHNICAL & SERVICE MANUAL
[Model Name]
<Branch box>
PAC-MK53BC
PAC-MK53BCB
PAC-MK33BC
PAC-MK33BCB
BRANCH BOX
[Service Ref.]
PAC-MK53BC
PAC-MK53BCB
PAC-MK33BC
PAC-MK33BCB
PAC-MK53BC
CONTENTS
1. SAFETY PRECAUTION ······································· 2
2. OVERVIEW OF UNIT ··········································· 5
3. SPECIFICATIONS ················································ 9
4. OUTLINES AND DIMENSIONS ···························10
5. WIRING DIAGRAM ············································· 12
6. NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION·············13
7. TROUBLESHOOTING ········································ 17
8. DISASSEMBLY PROCEDURE ··························· 26
PARTS CATALOG (OCB664)
HFC
utilized
R410A
March 2018
No. OCH664
Note:
• This service manual
describes technical data of
branch box. As for indoor
units and outdoor unit,
refer to its service manual.
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Summary of Contents for Mitsubishi Electric PAC-MK53BC
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Page 1: Table Of Contents
R410A SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS March 2018 No. OCH664 TECHNICAL & SERVICE MANUAL [Model Name] [Service Ref.] Note: • This service manual <Branch box> describes technical data of PAC-MK53BC branch box. As for indoor PAC-MK53BC units and outdoor unit, refer to its service manual. PAC-MK53BCB PAC-MK53BCB PAC-MK33BC PAC-MK33BC PAC-MK33BCB PAC-MK33BCB CONTENTS 1. SAFETY PRECAUTION ······································· 2 2. -
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) If moisture or foreign matter might have entered the refrigerant piping during service, ensure to remove them. [2] Additional refrigerant charge When charging directly from cylinder (1) Check that cylinder for R410A on the market is a syphon type.
- 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. 1 Thickness of pipes Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness shown below. (Never use pipes of 0.7 mm or below.) Diagram below: Piping diameter and thickness Thickness (mm) Nominal Outside dimensions (in) diameter (mm) R410A 6.35 9.52 12.70 15.88 — 19.05 2 Dimensions of flare cutting and flare nut The component molecules in HFC refrigerant are smaller compared to conventional refrigerants. In addition to that, R410A is a refrigerant, which has higher risk of leakage because its working pressure higher than that of other refriger- ants. Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been speci- fied separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also has partly been changed to increase strength as shown below. Set copper pipe correctly referring to copper pipe flaring dimensions for R410A below. For 1/2” and 5/8” inch pipes, the dimension B changes. Use torque wrench corresponding to each dimension.
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Page 5: Overview Of Unit
OVERVIEW OF UNIT 2-1. SYSTEM OUTLINE The additional connection of the branch box together with employment of the compact trunk-looking outdoor unit can successfully realize a long distance piping for big houses. Equipped with a microprocessor, the branch box can translate the transmission signal of indoor units to achieve the optimum control. 2-1-1. System example Indoor unit (Ceiling concealed type) Number of connectable indoor units (MAX.) Development No. : A, B, ···,etc. M X Y - Control and refrigerant A : New A control and R410A Indoor unit (Wall mounted type) Power supply... - Page 6 2-2. INSTALLATION 2-2-1. Space required for Installation and servicing for branch box for PAC-MK53/33BC (1) Front View (Fig. 2-1) A Branch box B On the side of piping (2) Side View (Fig. 2-2, Fig. 2-3, Fig. 2-4) C For indoor installations D Ceiling board E Maintenance hole F Reactor box (Optional parts) *1: A minimum 350 mm is required for 90° bends in refrigerant piping. *2: A is “Min 200 mm”. In the case of less than 200 mm (for example A is 100 mm), the exchange work of branch box from a maintenance hole becomes difficult (Only exchange work of a PCB, linear expansion valve coils and sensors is possible).
- Page 7 2-2-2. Space required for Installation and servicing for branch box for PAC-MK53/33BCB (1) Front View (Fig. 2-6) A Branch box B On the side of piping (2) Side View (Fig. 2-7, Fig. 2-8, Fig. 2-9) C For indoor installations D Ceiling board E Maintenance hole *1: A minimum 350 mm is required for 90° bends in refrigerant piping. *2: A is “Min. 200 mm” <recommendation>. In the case of less than 200 mm (for example A is 100 mm), the exchange work of branch box from a maintenance hole becomes difficult (Only exchange work of a PCB, linear expansion valve coils and sensors is possible). To install the optional reactor box, set A to Min. 270 mm <recommendation> (Fig. 2-9) *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. 2-8, Fig. 2-9), and “Min. 300 mm” is needed as distance A.
- Page 8 2-3. 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.
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Page 9: Specifications
SPECIFICATIONS PAC-MK53BC PAC-MK33BC PAC-MK53BC PAC-MK33BC Model Name Maximum 5 Connectable number of indoor units Maximum 3 Power supply (from outdoor unit) ~/N, 220/230/240 V, 50 Hz, ~/N, 220/230 V, 60 Hz Input 0.003 Running current 0.05 (Max. 6) External finish... -
Page 10: Outlines And Dimensions
OUTLINES AND DIMENSIONS Unit: mm PAC-MK53BC SUSPENSION BOLT PITCH SUSPENSION BOLT : W3/8(M10) REFRIGERANT PIPE BRAZED CONNECTION TO OUTDOOR UNIT { 6.35 { 6.35 { 6.35 { 6.35 { 6.35 { 9.52 LIQUID PIPE GAS PIPE { 9.52 { 9.52 { 9.52... - Page 11 Unit: mm PAC-MK53BCB SUSPENSION BOLT PITCH SUSPENSION BOLT : W3/8(M10) REFRIGERANT PIPE BRAZED CONNECTION TO OUTDOOR UNIT { 6.35 { 6.35 { 6.35 { 6.35 { 6.35 { 9.52 LIQUID PIPE { 9.52 { 9.52 { 9.52 { 9.52 { 12.7 { 15.88 GAS PIPE TERMINAL BLOCK...
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Page 12: Wiring Diagram
2 Turn off for 3 sec. SW12 Address Setting tens digit 3 Repeat 1 to 2 . LEV-A~E Linear expansion valve 6 D and E for PAC-MK53BC (B) only TH-A~E Thermistor <Gas pipe> TB2B Terminal block <To Power Supply> Transmission line... -
Page 13: Necessary Conditions For System Construction
NECESSARY CONDITIONS FOR SYSTEM CONSTRUCTION 6-1. TRANSMISSION SYSTEM SETUP OCH664... - Page 14 6-2. REFRIGERANT SYSTEM DIAGRAM ■ ■ PAC-MK53BC PAC-MK53BCB PAC-MK33BC PAC-MK33BCB Thermistor (TH-A–E) Thermistor (TH-A–C) (Gas pipe temperature) (Gas pipe temperature) LEV A–E LEV A–C (Linear expansion valve) (Linear expansion valve) Strainer Strainer #100 #100 Strainer Strainer #100 #100 Capillary Capillary...
- Page 15 6-3. TYPICAL CONTROL SYSTEM OC : Outdoor unit TB3A TB5/TB15 Branch Box A-IC MA-RC M-IC : M-NET Control indoor unit (City Multi indoor unit) (01) (51) A-IC : A-control indoor unit TB3B TB5/TB15 M1 M2 S M1 M2 S MA-RC : MA Remote controller A-IC MA-RC (02) WL-RC : Wireless Remote controller TB3C TB5/TB15 A-IC MA-RC (03) TB3D A-IC WL-RC (04) TB3E A-IC WL-RC (05) (53) TB3A...
- Page 16 ( 5) Group setting 1 MA group or M-NET group setting cannot be set. (6) Restricted functions The following functions of system controller cannot 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. OCH664...
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Page 17: Troubleshooting
TROUBLESHOOTING 7-1. HOW TO CHECK THE PARTS BRANCH BOX : PAC-MK53BC PAC-MK33BC PAC-MK53BCB PAC-MK33BCB Parts name Check points Thermistor (TH-A–E) Disconnect the connector then measure the resistance with a tester. <Gas pipe> (At the ambient temperature 10 to 30°C) Thermistor R =15k" ± 3% < Thermistor for lower temperature > Fixed number of B=3480 ± 2% Rt=15exp { 3480( ) } 273+t 10: 9.7 k" 15: 7.9 k" 20: 6.4 k"... - Page 18 Linear expansion valve (LEV) in Branch box (1) Operation summary of the linear expansion valve • Linear expansion valve opens/closes 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. <Connection between the branch box controller board and the linear expansion valve> branch box controller board 12 V DC Drive circuit Blue Orange Yellow White Connector LEV-A LEV-B LEV-C LEV-D LEV-E <Output pulse signal and the valve operation> Output Output (Phase)
- Page 19 (3) How to attach and detach the coil of linear expansion valve <Composition> Linear expansion valve is separable into the main body and the coil as shown in the diagram below. Main body Coil Lead wire Stopper <How to detach the coil> 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. Be sure to detach the coil holding main body firmly. Otherwise pipes can bend due to stress. <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 firmly attached to pipe B, coil may be detached from the main body and that can cause defective operation of linear expan- sion valve.
- Page 20 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 21 7-2. TEST POINT DIAGRAM Branch box controller board PAC-MK53BC PAC-MK33BC PAC-MK53BCB PAC-MK33BCB LEV-A to E TH-A to E Connect to thermistor-A to E Connect to LEV-A to E TH-D and E for PAC-MK53BC(B) only LEV-D and E for PAC-MK53BC(B) only CN3M Connected to the terminal block (TB5) (M-NET transmission con- necting wire) 24–30 V DC (non polar) LED1,LED2 ·Startup Main power supply (220/230/240 V AC) ·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...
- Page 22 7-3. INTERNAL SWITCH FUNCTION TABLE ■ The black square ( ) indicates a switch position. OCH664...
- Page 23 7-4. BRANCH BOX UNIT OPERATION MONITOR FUNCTION [When optional 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 check code by controlling DIP SW2 on ‘A-Control Service Tool’. <Table1> SW5 setting The black square (■) indicates a switch position. SW5 setting Detail Operation indicator: Common 2 3 4 5 6 • SW2 - Use to set the displayed item • SW5 - Use to set the displayed unit Indoor-A 2 3 4 5 6 Indoor-B...
- Page 24 The black square (■) indicates a switch position. SW2 setting Display detail SW5 setting* Explanation for display Unit ― ― Common Not used Individual unit Actual opening pulse 0 to 500 of LEV (When it is 100 pulse or more, it displays a hundredth, (Direct-operated tens, and unit digit by turns.) conversion value) Example: 0 to 500 Pulse 2 3 4 5 6 When 150 pulse, 0.5 s 0.5 s 2.0 s Common Not used ― ― Individual unit Displays a check code, and M-NET address of the unit Error history which the check code was detected. 2 3 4 5 6 Example: If the check code 2520 is detected in the address3, Code...
- Page 25 The black square (■) indicates a switch position. SW2 setting Display detail Explanation for display Unit SW5 setting* ― ― Common Not used Individual unit Indoor thermistor −39 to 88 <pipe temperature/ 2 3 4 5 6 (When the temperature is 0: or less, "−" and temperature 2-phase> (TH5) are displayed by turns.) Example: When −5:, 0.5 s 0.5 s 2.0 s − Common Not used ― ― Individual unit −42 to 91 Branch box pipe thermistor (TH-A, B, C, (When the temperature is 0: or less, "−" and temperature 2 3 4 5 6 D, E) are displayed by turns.) Example:...
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Page 26: Disassembly Procedure
DISASSEMBLY PROCEDURE BRANCH BOX: PAC-MK53BC PAC-MK33BC PHOTO: PAC-MK53BC PAC-MK53BCB PAC-MK33BCB OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the controller cover and under panel Photo 1 (1) R emove 3 controller cover fixing screws (4 o 10) to Under panel fixing screws detach the controller cover. (See Photo 1) (2) R emove 4 under panel fixing screws (4 o 10) to remove the under panel. (See Photo 1) Controller cover fixing screw Under panel Controller cover Controller cover fixing screws 2. - Page 27 OPERATING PROCEDURE PHOTOS/FIGURES 3. Removing the LEV coil (LEV-A–E*) Photo 3 (1) R emove the controller cover. (See Photo 1) Bands (2) R emove the under cover. (See Photo 1) (3) R emove 8 insulations, then remove 9 pipe cover fixing Header assy screws (4 x 10). (See Photo 2-1) Rubber mount (4) C ut the bands that fixes the lead wire, then pull out the LEV coil(s) (LEV-A – E*). (See Photo 3) Bands (5) L oosen the insulation sheet which bundles the LEV lead LEV assy wires.
- Page 28 OPERATING PROCEDURE PHOTOS/FIGURES 5. Removing the LEV assy Photo 5-1 LEV assy (1) R emove the controller cover. (See Photo 1) (2) R emove the under panel. (See Photo 1) (3) R emove 8 the insulations, then remove 9 pipe cover fix- ing screws (4 x 10). (See Photo 2-1) (4) L oosen the side clamps, then disconnect the LEV con- nectors on the controller board. Earth lead wire (5) R emove the earth lead wires from the LEV assy. (6) P ull out the lead wires through the hole to the controller board side. <Removing the header assy> (6) C ut the band which fixes the header assy and LEV assy together, then remove the rubber mount. (See Photo 3) (7) R emove the header assy. (See Photo 5-1)
- Page 29 OCH664...
- Page 30 HEAD OFFICE : TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO100-8310, JAPAN cCopyright 2018 MITSUBISHI ELECTRIC CORPORATION Published: Mar. 2018 No.OCH664 Made in Japan Specifications are subject to change without notice.