Table of Contents
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TopPage
CHAPTER 1. SPECIFICATION
[1]
SPECIFICATION.................................... . ....... 1-1
[2]
EXTERNAL DIMENSION....................... . ....... 1-2
[3]
WIRING DIAGRAM................................ . ....... 1-3
[4]
ELECTRICAL PARTS ............................ . ....... 1-3
[1]
BLOCK DIAGRAMS............................... . ....... 2-1
[2]
[3]
FUNCTION ............................................ . ....... 2-9
CHAPTER 3. FUNCTION AND OPERATION OF PRO-
TECTIVE PROCEDURES
[1]
PROTECTION DEVICE FUNCTIONS AND
OPERATIONS........................................ . ....... 3-1
[2]
THERMISTOR ERROR ......................... . ....... 3-3
[3]
ACTERISTICS ....................................... . ....... 3-5
[4]
HOW TO OPERATE THE OUTDOOR
Parts marked with "
" are important for maintaining the safety of the set. Be sure to replace these parts with specified ones for maintaining the
safety and performance of the set.
SERVICE MANUAL
SPLIT TYPE
AIR TO AIR HEAT PUMP
12KHR-N
MODEL
In the interests of user-safety (Required by safety regulations in some
countries) the set should be restored to its original condition and only
parts identical to those specified should be used.
CONTENTS
UNIT INDEPENDENTLY ............................... 3-6
[5]
[6]
OD ................................................................. 3-8
[7]
OUTDOOR UNIT CHECK METHOD .......... 3-10
[8]
TROUBLESHOOTING GUIDE .................... 3-14
CHAPTER 4. REFRIGERATION CYCLE
[1]
FLOW FOW REFRIGERANT ........................ 4-1
........ 2-3
[2]
STANDARD CONDITION.............................. 4-1
[3]
TEMPERATURE AT EACH PART AND
PRESSURE IN 3-WAY VALVE ...................... 4-1
[4]
PERFORMANCE CURVES........................... 4-2
CHAPTER 5. DISASSEMBLING PROCEDURE
[1]
DISASSEMBLY OF INDOOR UNIT............... 5-1
[2]
DISASSEMBLY OF OUTDOOR UNIT......... 5-10
Parts Guide
This document has been published to be used for
after sales service only.
The contents are subject to change without notice.
12KHR-N
........ 3-6
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Summary of Contents for IVT 12KHR-N
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Page 1: Table Of Contents
12KHR-N TopPage SERVICE MANUAL SPLIT TYPE AIR TO AIR HEAT PUMP 12KHR-N MODEL In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used. -
Page 2: Specification
12KHR-N 12KHR-N CHAPTER 1. SPECIFICATION [1] SPECIFICATION 1. 12KHR-N MODEL INDOOR UNIT OUTDOOR UNIT ITEMS 12KHR-N Rated cooling capacity (Min– Max.) 3.5 (0.9 - 4.0) Rated heating capacity (Min–Max.) 4.6 (0.9 - 6.5) Moisture removal (at cooling) Liters/h Electrical data... -
Page 3: External Dimension
12KHR-N [2] EXTERNAL DIMENSION 1. Indoor unit Unit 18.5 INVERTER AIR CONDITIONER 22.0 2. Outdoor unit 37.5 167.5 1 – 2... -
Page 4: Wiring Diagram
12KHR-N [3] WIRING DIAGRAM 1. Indoor unit W I R I N G D I A G R A M INVERTER AIR-CONDITIONER LED INDICATION FOR SELF-DIAGNOSIS Blinking NO. Short circuit of the outdoor thermistor Overheat of the compressor Open circuit of the outdoor thermistor... -
Page 5: Chapter 2. Explamation Of Circuit And Op- Eration Block Diagrams
12KHR-N 12KHR-N CHAPTER 2. EXPLAMATION OF CIRCUIT AND OPERATION [1] BLOCK DIAGRAMS 1. Indoor unit Rectification circuit DC power supply circuit AC power 3.15A Fuse Fan motor PWM control circuit Indoor fan motor Rotation pulse input circuit Fan motor pulse detect... - Page 6 12KHR-N 2. Outdoor unit AC clock circuit protection Pulse amplitube modulation circuit IGBT protection Unit-unit wiring (AC power Power supply circuit Smoothing Power factor Filter circuit converter circuit circuit and serial signals) CPU oscillator circuit 3.15A DC overvoltage detection circuit...
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Page 7: Microcomputer Control System
12KHR-N [2] MICROCOMPUTER CONTROL SYSTEM 1. Indoor unit 1.1. Electronic control circuit diagram 2 – 3... - Page 8 12KHR-N 1.2. Display circuit diagram 2 – 4...
- Page 9 12KHR-N 1.3. Printed wiring board For 2KHN model main PWB From cluster unit From fan motor From horizontal louver motor To vertical louver motor(left) To vertical louver motor(right) From sensor PWB From pipe thermistor (relay connector) For 2KHN model sensor PWB To main PWB 2 –...
- Page 10 12KHR-N For 2KHN model connection PWB From hang From panel From panel From display From display From panel From panel From hang motor left motor left SW left PWB(black) PWB(yellow) SW right motor right motor right To main PWB To main PWB...
- Page 11 12KHR-N 2. Outdoor unit 2.1. Electronic control circuit diagram 2 – 7...
- Page 12 12KHR-N 2.2. Printed wiring board To Terminal Board To Terminal Board To Control Box (N)(Blue) (2) (Red) To Terminal Board (Green/Yellow) (1) (Brown) From 4 Way Valve From Expansion Valve From Thermistor From Terminal Board To Reactor (Gray) From Fan...
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Page 13: Function
12KHR-N [3] FUNCTION 1. Function 1.1. Restart control 1.5. Indoor unit overheat prevention control Once the compressor stops operating, it will not restart for 180 sec- During heating operation, if the temperature of the indoor unit heat onds to protect the compressor. - Page 14 12KHR-N 1.9. Peak control 1.14. Power ON start If the current flowing in the air to air heat pump exceeds the peak con- If a jumper cable is inserted in the location marked with HAJP on the trol current the operation frequency is decreased until the current...
- Page 15 12KHR-N 1.17. Adjusting the air flow direction 1.17.2 Horizontal air flow direction 1.17.1 Vertical air flow direction Press the HORIZONTAL AIR FLOW but- ton to set the desired air flow direction Press the VERTICAL AIR FLOW button to set the desired air flow direction.
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Page 16: Operations
12KHR-N 1.18. Difference of operation in Auto and Manual modes In the Auto mode, the temperature setting is automatically determined based on the outside air temperature. In addition, the air to air heat pump oper- ation differs from the operation in the Manual mode as explained below. - Page 17 12KHR-N • Power ON/OFF • Full power setting • Automatic operation mode setting • Internal cleaning • Swing louvre 1.25.3 Disabling auto restart function • Plasmacluster mode By removing (cutting) jumper 8 (JP8) on the printed circuit board (PCB), the auto restart function can be disabled.
- Page 18 12KHR-N Reactor Stored energy IGBT ON IGBT OFF IGBT 3.2. High power factor control circuit This circuit brings the operating current waveform closer to the waveform of commercial power supply voltage to maintain a high power factor. Because of the capacitor input, when the PAM circuit is OFF, the phase of the current waveform deviates from the voltage waveform as shown below.
- Page 19 12KHR-N 3.3. PAM protection circuit To prevent excessive voltage of PAM output from (Overvoltage detection) damaging the IPM and electrolytic capacitor as well as the control printed circuit board (PCB), this circuit monitors the PAM output voltage and turns off the...
- Page 20 12KHR-N 4. Explanation of IPM drive circuit The IPM for compressor drive is made by Mitsubishi Electric. The power supply for the IPM drive and the shunt resistance for overcurrent detection, are provided outside the IPM. 4.1. IPM drive power supply circuit The power supply for the upper-phase IGBT (HU, HV, HW) drive employs a bootstrap system, and provides power to the upper-phase IC.
- Page 21 12KHR-N 4.1.2 DC overcurrent detection circuit When a current of about 25 A or higher flows through the shunt resistance (R49) on the control printed circuit board (PCB), the voltage at this resis- tance is input to IPM CIN pin (15). Then, the gate voltage of the lower-phase IGBT (LU, LV, LW) inside the IPM turns OFF to cut off the overcurrent. At the same time, an L output of more then 20 s.
- Page 22 12KHR-N 5. 120 energizing control (digital position detection control) This control system detects the digital position detection signal and adjusts the rate of acceleration/deceleration accordingly. The motor's induced voltage waveform is input to the comparator in the form of PWM-switched pulse waveform, and a position detection signal is generated as a reference voltage equaling 1/2 of 280 VDC.
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Page 23: Protection Device Functions And Operations
12KHR-N 12KHR-N CHAPTER 3. FUNCTION AND OPERATION OF PROTECTIVE PROCEDURES [1] PROTECTION DEVICE FUNCTIONS AND OPERATIONS Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor Indoor Outdoor unit unit unit error display Indoor unit fan lock Operation stops if there is no... - Page 24 12KHR-N Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor Indoor Outdoor unit unit unit error display AC overcurrent Operating frequency lowers if out- When compressor is Operation OFF or ON Yes $1 error door AC current exceeds peak in operation control current value.
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Page 25: Air To Air Heat Pump Operation In Thermistor Error
12KHR-N Function Operation Self-diagnosis result display Description Detection period Reset condition Indoor Indoor Outdoor unit unit unit error display 26 Compressor rota- Compressor stops if there is no Compressor operat- Operation OFF or ON Yes $3 tion error (at 120... - Page 26 12KHR-N 2. Outdoor unit Item Mode Control opera- When resis- Short-circuit When resis- Open-circuit tion tance is low tance is high (temperature (temperature judged higher judged lower than actual) than actual) Compressor Cooling Expansion valve Compressor Compressor high Layer short-cir-...
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Page 27: Thermistor Temperature Characteristics
12KHR-N [3] THERMISTOR TEMPERATURE CHARACTERISTICS 1. Indoor unit thermistor temperature characteristics Figure 1 Temperature properties of indoor thermistors Room temperature Thermistor Signal Color thermistor TH1 (CN10 1 - 3 ) Room temperature Yellow Heat exchange Heat exchange Orange thermistor TH2 (CN11 1 - 2 ) To measure the resistance, first remove the soldering as shown at right. -
Page 28: Unit Independently
12KHR-N [4] HOW TO OPERATE THE OUTDOOR UNIT INDEPENDENTLY 1. Cooling in 40 Hz fixed mode To operate the outdoor unit independently, short-circuit the sections indicated by arrows in the diagram below with an adapter, and apply 220-240 VAC between (1) and (N) on the terminal board of the outdoor unit. This allows the outdoor unit to be operated in cooling mode independently. - Page 29 12KHR-N Main cause Inspection method Normal value/condition Remedy Dew condensation on light receiv- Check for water and rust. Signal should be received within Take moisture-proof measure for ing unit. range specified in manual. lead wire outlet of light receiving section.
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Page 30: Malfunction (Parts) Check Method
12KHR-N [6] MALFUNCTION (PARTS) CHECK METHOD 1. Procedure for determining defective outdoor unit IPM/compressor The following flow chart shows a procedure for locating the cause of a malfunction when the compressor does not start up and a DC overcurrent indi- cation error occurs. - Page 31 12KHR-N 2. Procedure for determining defective expansion valve Measure resistance in expansion valve coil. Normal resistance between red terminal of expansion valve lead wire and each terminal: about 46 (at 20 (red) Checker Insert checker shown at left into connector (CN12) on control PWB, and operate air conditioner.
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Page 32: Outdoor Unit Check Method
12KHR-N 5. IPM check method Turn off the power, let the large capacity electrolytic capacitor (C10) discharge completely, and dismount the IPM. Then, using a tester, check leak current between C and E. When using a digital tester, the (+) and (-) tester lead wires in the table must be reversed. - Page 33 12KHR-N 1. Checking procedures Item Check method Normal value/condition Remedy Preparation Disconnect compressor cords (white, orange, red: 3 wires) from compres- sor terminals, and connect simulated load (lamp used as load). Operate air conditioner in cooling or heating test operation mode.
- Page 34 12KHR-N 2. Troubleshooting of outdoor unit electric components Check 220-240VAC input voltage. Check 320VDC Short-circuit in DC fan motor Does LED light? between IPM pins Short-circuit in IPM (20) and (24) ? Short-circuit in diode bridge Blown fuse Defective electrolytic capacitor...
- Page 35 12KHR-N 3. Caution in checking printed circuit boards (PWB) 3.1. Non-insulated control circuit The GND terminals of the low-voltage circuits (control circuits for microcomputer and thermistors and drive circuits for expansion valve and relays) on the control printed circuit board (PWB) are connected to the compressor drive power supply (320-VDC negative terminal). Therefore, exercise utmost caution to prevent electric shock.