Mitsubishi Electric PKA-A18HA6 Service Manual

Mitsubishi Electric PKA-A18HA6 Service Manual

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Indoor unit
[Model Name]
[Service Ref.]
1. REFERENCE MANUAL ................................... 2
2. SAFETY PRECAUTION ................................... 3
3. PARTS NAMES AND FUNCTIONS ................. 4
4. SPECIFICATIONS ........................................... 10
5. NOISE CRITERION CURVES .........................11
6. OUTLINES AND DIMENSIONS ...................... 12
7. WIRING DIAGRAM .........................................13
9. TROUBLESHOOTING .................................... 15
10. SPECIAL FUNCTION ..................................... 29
11. DISASSEMBLY PROCEDURE ....................... 32
December 2014
No. OCH580
• This manual describes
service data of the indoor
units only.
• RoHS compliant products
have <G> mark on the
spec name plate.


Table of Contents

Summary of Contents for Mitsubishi Electric PKA-A18HA6

  • Page 1: Table Of Contents

    [Service Ref.] Notes: PKA-A12HA6 • This manual describes PKA-A12HA6 service data of the indoor units only. PKA-A18HA6 • RoHS compliant products PKA-A18HA6 have <G> mark on the spec name plate. CONTENTS 1. REFERENCE MANUAL ........2 2. SAFETY PRECAUTION ........3 3.
  • Page 2: Cool

    REFERENCE MANUAL 1-1. OUTDOOR UNIT SERVICE MANUAL Model Name Service Ref. Service Manual No. PUZ-A18/24/30/36NHA6 PUZ-A18/24/30/36NHA6 OCH577 PUZ-A18/24/30/36NHA6-BS PUZ-A18/24/30/36NHA6-BS PUY-A12/18/24/30/36NHA6 PUY-A12/18/24/30/36NHA6 OCB577 PUY-A12/18/24/30/36NHA6-BS PUY-A12/18/24/30/36NHA6-BS Remote controller (Optional parts) Radio frequency interface Wired remote controller IR wireless remote controller COOL AUTO HEAT RF thermostat TEMP.
  • Page 3: Safety Precaution

    SAFETY PRECAUTION 2-1. ALWAYS OBSERVE FOR SAFETY Before obtaining access to terminal, all supply circuits must be disconnected. 2-2. CAUTIONS RELATED TO NEW REFRIGERANT Cautions for units utilising refrigerant R410A Use the following tools specifically designed for Use new refrigerant pipes. use with R410A refrigerant.
  • Page 4: Parts Names And Functions

    [2] Additional refrigerant charge When charging directly from cylinder · Check that cylinder for R410A on the market is syphon type. · Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.) Unit Gravimeter [3] Service tools Use the below service tools as exclusive tools for R410A refrigerant.
  • Page 5 Wired remote controller (Option) Controller interface The functions of the function buttons change depending on the screen. Refer to the button function guide that appears at the bottom of the LCD for the functions they serve on a given screen. When the system is centrally controlled, the button function guide that corresponds to the locked button will not appear.
  • Page 6 Display The main display can be displayed in two different modes: “Full” and “Basic”. The initial setting is “Full”. To switch to the “Basic” mode, change the setting on the Main display setting. (Refer to operation manual included with remote controller.) <Full mode>...
  • Page 7 Menu structure Press the button. MENU Main menu Move the cursor to the desired item with the buttons, and press the button. SELECT Vane · Louver · Vent. (Lossnay) High power Timer On / Off timer Auto-Off timer Weekly timer Restriction Temp.
  • Page 8 Main menu list Setting and display items Setting details Vane · Louver · Vent. (Lossnay) Use to set the vane angle. • Select a desired vane setting from five different settings. Use to turn ON / OFF the louver. • Select a desired setting from "ON" and "OFF." Use to set the amount of ventilation.
  • Page 9 ● IR wireless remote controller (Option) CHECK TEST RUN display CHECK and TEST RUN display indicate that the unit is being checked or test-run. display MODEL SELECT Blinks when model is selected. display Lights up while the signal is transmitted to the indoor unit when the button is pressed.
  • Page 10: Specifications

    (in) 249 (9-13/16) mm (in) 295 (11-5/8) mm (in) Weight 13 (29) kg (lb) PKA-A18HA6 Service Ref. 1 phase, 60 Hz, 208/230 V Power supply(phase, cycle, voltage) Max. Fuse Size Min.Circuit Ampacity External finish White Munsell 1.0Y 9.2/0.2 Plate fin coil...
  • Page 11: Noise Criterion Curves

  • Page 12: Outlines And Dimensions

    OUTLINES AND DIMENSIONS PKA-A12HA6 PKA-A18HA6 Unit: in (mm) 15-3/16(387) 7-1/2(192) Top side Mount board 23-9/16(599) Front side Right side 9-13/16(249) 3/16(5) Left side 27-1/16(688) 6-1/16(155) 2-1/8 (55) Knock out hole 35-3/8(898) Knock out hole for left piping for right piping...
  • Page 13: Wiring Diagram

    WIRING DIAGRAM PKA-A12HA6 PKA-A18HA6 [Explanation of symbols] Symbol Name Symbol Name Indoor controller board Vane motor CN2L Connector (LOSSNAY) Fan motor CN30 Connector (LLC) Switch board CN32 Connector ( Remote switch) SWE2 Emergency operation CN41 Connector (HA terminal-A) Terminal block(Indoor unit Power (option))
  • Page 14: Refrigerant System Diagram

    REFRIGERANT SYSTEM DIAGRAM PKA-A12HA6 PKA-A18HA6 Strainer (#50) Heat exchanger Refrigerant GAS pipe connection (Flare) Thermistor TH2 Refrigerant flow in cooling Pipe temperature(Liquid) Refrigerant flow in heating Thermistor TH5 (Cond./ Eva.temperature) Refrigerant LIQUID pipe connection (Flare) Thermistor TH1 (Room temperature) Strainer (#50)
  • Page 15: Troubleshooting

    TROUBLESHOOTING 9-1. TROUBLESHOOTING <Check code displayed by self-diagnosis and actions to be taken for service (summary)> Present and past check codes are logged, and they can be displayed on the wired remote controller and control board of out- doorunit. Actions to be taken for service, which depends on whether or not the trouble is reoccurring in the field, are summa- rized in the table below.
  • Page 16 9-2. MALFUNCTION-DIAGNOSIS METHOD BY REMOTE CONTROLLER <In case of trouble during operation> When a malfunction occurs to air conditioner, both indoor unit and outdoor unit will stop and operation lamp blinks to inform unusual stop. < Malfunction-diagnosis method at maintenance service> ■IR wireless remote controller [Procedure] 1.
  • Page 17 • Refer to the following tables for details on the check codes. [Output pattern A] Beeper sounds Beep Beep Beep Beep Beep Beep Beep OPERATION · · · Repeated INDICATOR lamp blink pattern Approx. 2.5 s 0.5 s 0.5 s 0.5 s Approx.
  • Page 18 • On IR wireless remote controller The continuous buzzer sounds from receiving section of indoor unit. Blink of operation lamp • On wired remote controller Check code displayed in the LCD. (Refer to the previous page, check code.) • If the unit cannot be operated properly after the test run, refer to the following table to find out the cause. Symptom Cause Wired remote controller...
  • Page 19 Note: Errors to be detected in outdoor unit, such as codes starting with F, U or E (excluding E0 to E7), 9-3. SELF-DIAGNOSIS ACTION TABLE are not covered in this document. Please refer to the outdoor unit service manual for the details. Abnormal point and detection method Countermeasure Check code...
  • Page 20 Abnormal point and detection method Countermeasure Check code Cause Freezing/overheating protection is work- (Cooling or drying mode) (Cooling or drying mode) 1 Clogged filter (reduced airflow) 1 Check clogs of the filter. 1 Freezing protection (Cooling mode) 2 Short cycle of air path 2 Remove shields.
  • Page 21 Abnormal point and detection method Countermeasure Check code Cause Pipe temperature thermistor/ 1 Defective thermistor 1–3 Check resistance value of thermistor. For characteristics, refer to (P1) above. Condenser-Evaporator (TH5) characteristics 2 Check contact failure of connector (CN44) on 1 The unit is in 3-minute resume protec- 2 Contact failure of connector the indoor controller board.
  • Page 22 Abnormal point and detection method Countermeasure Check code Cause Remote controller transmission 1 Set a remote controller to main, and the 1 2 remote controllers are set as error(E3)/signal receiving error(E5) other to sub. “main.” 1 Abnormal if remote controller could not (In case of 2 remote con- find blank of transmission path for 6 sec- trollers)
  • Page 23 9-4. TROUBLESHOOTING BY INFERIOR PHENOMENA Note: Refer to the manual of outdoor unit for the detail of remote controller. Phenomena Cause Countermeasure (1)Upward/downward vane The vane is not downward during defrosting and heat Normal operation (The vane is set to performance failure preparation and when the thermostat is OFF in HEAT horizontal regardless of remote control.)
  • Page 24: Emergency Operation

    9-5. EMERGENCY OPERATION 9-5-1. When IR wireless remote controller fails or its battery is exhausted When the remote controller cannot be used When the batteries of the remote controller run out or the remote controller malfunctions, the emergency operation can be done using the emergency buttons.
  • Page 25 9-6. HOW TO CHECK THE PARTS PKA-A12HA6 PKA-A18HA6 Parts name Check points Room temperature Disconnect the connector then measure the resistance with a tester. thermistor (TH1) (At the ambient temperature 50 to 86_F [10 to 30°C]) Liquid pipe thermistor Normal...
  • Page 26 9-6-2. DC Fan motor (fan motor/indoor controller circuit board) Check method of DC fan motor (fan motor/indoor controller circuit board) Notes · High voltage is applied to the connecter (CNMF) for the fan motor. Pay attention to the service. · Do not pull out the connector (CNMF) for the motor with the power supply on. board and fan motor.) (It causes trouble of the indoor controller circuit Self check...
  • Page 27 9-7. TEST POINT DIAGRAM Indoor controller board PKA-A12HA6 PKA-A18HA6 CNMF Connect to the fan motor (MF) 1–3: 294–325 V DC CN105 4–3: 15 V DC 5–3: 0–6.5 V DC (Radio frequency interface) 6–3: 0 or 15 V DC CN01 Connect to the Terminal block (TB4) 1–3: 208/230 V AC...
  • Page 28 9-8. FUNCTIONS OF DIP SWITCH AND JUMPER WIRE Each function is controlled by the DIP switch and the jumper wire on indoor controller board. PKA-A12HA6 PKA-A18HA6 ■ The black square ( ) indicates a switch position. Jumper wire Setting by the DIP switch and jumper wire...
  • Page 29: Special Function

    SPECIAL FUNCTION 10-1. Rotation Function (and back-up function, 2nd stage cut-in function) This function is only available when using wired remote controller. 10-1-1. Operation (1) Rotation function (and Back-up function) Outline of functions · Main and sub units operate alternately according to the interval of rotation setting. Note: Main and sub unit should be set by refrigerant address.
  • Page 30 System constraint · This function is available only in cooling mode. Ex.) Set temp. by R/C = 68°F [20:] [2nd stage cut-in function]··· Request code number "322–324" Set point = 79°F [26:] When request code number is “323”. Room temp. ] Set point Room temp.
  • Page 31 (2) Rotation and back up operation PAR-31MAA Press the button. Main Main menu Maintenance Initial setting Select "Service" with the [Cursor] buttons ( ) or the [Page] buttons ( Service ), and press the button. Main display: Cursor Page Enter the current maintenance password (4 numerical digits). •...
  • Page 32: Disassembly Procedure

    DISASSEMBLY PROCEDURE PKA-A12HA6 PKA-A18HA6 Be careful when removing heavy parts. OPERATION PROCEDURE PHOTOS & ILLUSTRATIONS 1. REMOVING THE LOWER SIDE OF THE INDOOR Figure 1 UNIT FROM THE INSTALLATION PLATE (1) Remove the front panel. (2) Insert the screw driver to the corner hole at both left and right side as shown in the figure 1.
  • Page 33: Operation Procedure

    OPERATION PROCEDURE PHOTOS 3. REMOVING THE INDOOR CONTROLLER BOARD Photo 3 AND IR WIRELESS CONTROLLER BOARD Screw (side cover) Electrical box Screw (top cover) cover (top) (1) Remove the front panel. (Refer to step 2) Electrical box (2) Remove the room temp. thermistor TH1. (see Photo 3) cover (side) (3) Remove the electrical box covers (screw 4 ×...
  • Page 34 OPERATION PROCEDURE PHOTOS Electrical box cover (side) 5. REMOVING THE NOZZLE ASSEMBLY (with VANE Photo 7 Electrical box cover (top) and VANE MOTOR) AND DRAIN HOSE Screw (side cover) Screw (top cover) (1) Remove the front panel (Refer to step 2). (2) Remove the electrical box cover.
  • Page 35 OPERATION PROCEDURE PHOTOS 8. REMOVING THE LIQUID PIPE THERMISTOR AND Photo 12 Condenser/evaporator temp. thermistor (TH5) COND/EVA TEMP. THERMISTOR (1) Remove the front panel. (Refer to step 2) Heat exchanger (2) Remove the electrical box cover. (3) Remove the motor band. (4) Cut the wiring fixed band.
  • Page 36 HEAD OFFICE : TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN New publication, effective Dec. 2014 CCopyright 2014 MITSUBISHI ELECTRIC CORPORATION Specifications are subject to change without notice. Distributed in Dec. 2014 No. OCH580 Made in Japan...

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