SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS SPLIT-TYPE, AIR CONDITIONERS August 2019 No. OCH725 SERVICE MANUAL R32/R410A Indoor unit [Model Name] [Service Ref.] Notes: PCA-M71HA PCA-M71HA • This manual describes service data of the indoor units only. PCA-M71HA-ET PCA-M71HA-ET CONTENTS 1. REFERENCE MANUAL ........2 2.
SAFETY PRECAUTION MEANINGS OF SYMBOLS DISPLAYED ON THE UNIT This mark is for R32 refrigerant only. Refrigerant type is written on nameplate of outdoor unit. WARNING Read the OPERATION MANUAL carefully before operation. Service personnel are required to carefully read the OPERATION MANUAL and INSTALLATION MANUAL before operation. Further information is available in the OPERATION MANUAL, INSTALLATION MANUAL, and the like.
Page 4
[1] Warning for service (1) Do not alter the unit. (2) For installation and relocation work, follow the instructions in the Installation Manual and use tools and pipe components specifically made for use with refrigerant specified in the outdoor unit installation manual. (3) Ask a dealer or an authorized technician to install, relocate and repair the unit.
Page 5
[4] Cautions for unit using R32 refrigerant Basic work procedures are the same as those for conventional units using refrigerant R410A. However, pay careful attention to the following points. (1) Information on servicing (1-1) Checks on the Area Prior to beginning work on systems containing flammable refrigerants, safety checks are necessary to ensure that the risk of ignition is minimized.
Page 6
(3) Repair to intrinsically Safe Components Do not apply any permanent inductive or capacitance loads to the circuit without ensuring that this will not exceed the permissible voltage and current permitted for the equipment in use. Intrinsically safe components are the only types that can be worked on while live in the presence of a flammable atmos- phere.
Page 7
a) Become familiar with the equipment and its operation. b) Isolate system electrically. c) Before attempting the procedure, ensure that: • mechanical handling equipment is available, if required, for handling refrigerant cylinders; • all personal protective equipment is available and being used correctly; •...
Unit Electronic weighing scale [5] Service tools Use the below service tools as exclusive tools for R32/R410A refrigerant. Refer to the spec name plate on outdoor unit for the type of refrigerant being used. Tool name Specifications · Use the existing fitting specifications . (UNF1/2) Gauge manifold ·...
Page 9
3-2. WIRED REMOTE CONTROLLER (OPTION) <PAR-40MAA> The main display can be displayed in two different modes: "Full" and "Basic". The factory setting is "Full". To switch to the "Basic" mode, change the setting on the Main display setting Controller interface The functions of the function buttons change depending on the screen.
Page 10
Display Display The main display can be displayed in two different modes: “Full” and “Basic”. The factory 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 11
Menu structure Main menu Press the button. MENU Move the cursor to the desired item with the buttons, and press the button. SELECT Operation Vane · Louver · Vent. (Lossnay) High power Comfort Manual vane angle 3D i-see Sensor Timer menu Timer ON/OFF timer Auto-OFF timer...
Page 12
Continue from the previous page. Maintenance menu Error information Filter information Cleaning Auto descending panel Descending operation Descending adjustment Service menu Test run menu Test run Drain pump test run Maintenance information Model name input Serial No. input Dealer information input Initialize maintenance info.
Page 13
Main menu list Main menu Setting items Setting details Operation High power ** Use to reach the comfortable room temperature quickly. • Units can be operated in the High-power mode for up to 30 minutes. Timer Timer On/Off timer* Use to set the operation On/Off times. •...
SPECIFICATIONS Service Ref. PCA-M71HA(-ET) Mode Cooling Heating Power supply (phase, frequency, voltage) Single phase, 50Hz, 230V Input 0.10 Running current 0.43 Starting current 0.86 External finish Stainless steel Heat exchanger Plate fin coil Fan (drive) × No. Sirocco fan (direct) × 2 Fan motor output 0.04 Airflow (Low-High)
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 displayed on the wired remote controller or controller board of outdoor unit. Actions to be taken for service, which depends on whether or not the trouble is reoccurring in the field, are summarized in the table below.
Page 19
9-2. MALFUNCTION-DIAGNOSIS METHOD BY REMOTE CONTROLLER Self-check Select “Check” on the Service menu to bring up the Check menu screen. Check menu The type of menu that appears depends on the type of indoor units that are connected. Error history Diagnosis Smooth maintenance Request code...
Page 20
Error code [Output pattern A] Errors detected by indoor unit Check code Symptom Remark Intake sensor error E6, E7 Indoor/outdoor unit communication error Freezing/Overheating safeguard operation Communication error between indoor and outdoor units Pipe temperature error Controller signal receiving error Refrigerant leakage Refrigerant sensor error No corresponding...
Page 21
Note: Errors to be detected in outdoor unit, such as codes starting with F, U or E (excluding E0 to E7), are not covered in this document. Please 9-3. SELF-DIAGNOSIS ACTION TABLE refer to the outdoor unit's service manual for the details. Abnormal point and detection method Countermeasure Check code...
Page 22
Abnormal point and detection method Countermeasure Cause Check code Freezing/overheating protection is oper- (Cool or dry mode) (Cool or dry mode) ating 1 Clogged filter (reduced airflow) 1 Check clogs of the filter. 1 Freezing protection (Cooling mode) 2 Short cycle of air path 2 Remove blockage.
Page 23
Abnormal point and detection method Countermeasure Check code Cause Pipe temperature thermistor/Condenser- 1 Defective thermistor 1–3 Check resistance value of thermistor. Evaporator (TH5) For characteristics, refer to (P1). characteristics 2 Check contact failure of connector (CN29) 1 The unit is in 3-minute resume protec- 2 Contact failure of connector on the indoor controller board.
Page 24
Abnormal point and detection method Countermeasure Check code Cause Indoor/outdoor unit communication Note: error (Signal receiving error) Check LED display on the outdoor control 1 Abnormal if indoor controller board circuit board. (Connect A-control service cannot receive any signal normally for 6 tool, PAC-SK52ST.) minutes after turning the power on.
Page 25
9-4. TROUBLESHOOTING BY INFERIOR PHENOMENA Note: Refer to the manual of outdoor unit for the detail of remote controller. Phenomena Cause Countermeasure (1)LED2 on indoor controller board • When LED1 on indoor controller board is also off. 1 Check the voltage of outdoor power 1 Power supply of rated voltage is not supplied to out- supply terminal block (L, N) or (L3, N).
Page 26
Note: Refer to the outdoor unit's service manual for the detail of remote controller. Phenomena Cause Countermeasure (2)LED2 on indoor controller board • When LED1 on indoor controller board is also blinking. 1 Connection failure of indoor/outdoor unit connecting is blinking. 1 Check indoor/outdoor unit connecting wire wire for connection failure.
Page 27
9-6. HOW TO CHECK THE PARTS PCA-M71HA(-ET) Parts name Checkpoints Room temperature Disconnect the connector then measure the resistance with a tester. thermistor (TH1) (At the ambient temperature 10 to 30°C) Pipe temperature thermistor/liquid (TH2) Refer to the <Thermistor Characteristic Graph> below. Condenser/evaporator temperature thermistor (TH5)
Page 28
9-7. TEST POINT DIAGRAM 9-7-1. Power board PCA-M71HA(-ET) CNSK Connect to the indoor controller board (CNDK) Between 1to 3 220–240 V AC CN2S Connect to the indoor controller board (CN2D) Between 1to 312.6–13.7 V DC (Pin1(+)) OCH725...
Page 29
9-7-2. Indoor controller board PCA-M71HA(-ET) CN2D LED1 LED3 Connector to the indoor LED2 Power supply Transmission power board (CN2S) Power supply (I.B) (Indoor/outdoor) (12.5–13.7 V DC) (R.B) CN3C Transmission – (Indoor/outdoor) (0–24 V DC) CN22 Remote controller connecting wire – (10.4 –...
Page 30
9-8. FUNCTIONS OF DIP SWITCH AND JUMPER WIRE Each function is controlled by the dip switch and the jumper wire on controller board. SW1 and SW2 are equipped only for service parts. Model setting and capacity setting are preset in the nonvolatile memory of the controller board of the unit. ■...
SPECIAL FUNCTION 10-1. ROTATION FUNCTION (AND BACK-UP FUNCTION, 2ND STAGE CUT-IN FUNCTION) 10-1-1. Operation (1) Rotation function (and Back-up function) • Outline of functions · Main and sub unit operate alternately according to the interval of rotation setting. Main and sub unit should be set by refrigerant address. (Outdoor DIP switch setting) Refrigerant address "00"...
Page 32
10-1-2. How to set rotation function (Back-up function, 2nd stage cut-in function) You can set these functions by wired remote controller. (Maintenance monitor) NOTICE Both main and sub unit should be set in same setting. Every time replacing indoor controller board for servicing, the function should be set again. (1) Request Code List Rotation setting Setting No.
Page 33
(2) How to send a request code Press the [ ] button. Main Main menu Select "Service" with the and press the [ ] button. Service Enter the current maintenance password (4 numerical digits). Service menu • Move cursor to the digit you want to change with the button.
DISASSEMBLY PROCEDURE PCA-M71HA(-ET) : Indicates the visible parts in the photos/fi gures. OPERATING PROCEDURE PHOTOS/FIGURES 1. Removing the oil filter Figure 1 (1) Slide the oil filter towards you to remove. (See Figure 1) Oil filter 2. Removing the terminal block box cover Photo 1 Filter rails Filter rails...
Page 35
OPERATING PROCEDURE PHOTOS/FIGURES Photo 4 4. Removing the fan motor (1) Remove the oil filter. (See Figure 1) (2) Remove the control box cover. (See Photo 2) Filter rail Filter rail (3) Remove the room temperature thermistor connector (CN20) on the indoor controller board. (See Photo 3) (4) Remove a filter rail that is the nearest to the control box.
Page 36
OPERATING PROCEDURE PHOTOS/FIGURES Photo 8 6. Removing the pipe temperature thermistor Relay connector (1) Remove the oil filter. (See Figure 1) (2) Remove the fan guard. (See Photo 1) (3) Remove the terminal block box cover. (4) Remove the white relay connector (2P) in the terminal block box.
Page 37
OPERATING PROCEDURE PHOTOS/FIGURES Photo 13 9. Removing the guide vane (1) Remove the oil filter. (See Figure 1) Guide vanes Guide vanes Guide vanes (2) Remove the 2 filter rails. (See Photo 1, 4) (3) Remove the under panel. (See Photo 11) (4) Remove the drain pan.
Page 38
HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN CCopyright 2019 MITSUBISHI ELECTRIC CORPORATION Published: Aug. 2019 No. OCH725 Specifications are subject to change without notice. Made in Japan...