Revision B: • MXZ-2A20NA- 1 , MXZ-4A36NA, MSZ-FD, MSZ-D and MSY-D have been added. Please void OBT16 REVISED EDITION-A. No. OBT16 REVISED EDITION-B SERVICE TECHNICAL GUIDE Wireless type Models MS-A•WA MSZ-A•NA MSY-A•NA MSZ-FD•NA MSZ-D•NA MSY-D•NA · · · · · · · · · MU-A•WA MUZ-A•NA MUZ-A•NA MUY-A•NA MUZ-FD•NA MUZ-FD•NA MUZ-D•NA MUZ-D•NA MUY-D•NA U U U Inverter-controlled multi system type Models · MXZ-A•NA CONTENTS 1. MS MICROPROCESSOR CONTROL ·················· 4 2.
Revision A: • MXZ-3A30NA- 1 Revision B: • MXZ-2A20NA- 1 has been added. , MXZ-4A36NA, MSZ-FD, MSZ-D and MSY-D have been added.
1. MS MICROPROCESSOR CONTROL ···························································4 Indoor unit models Outdoor unit models MS-A09WA MS-A12WA MU-A09WA MU-A12WA 1-1. COOL OPERATION ···············································································4 1-2. DRY OPERATION ··················································································4 1-3. AUTO VANE OPERATION ·····································································6 2.
1 MS MICROPROCESSOR CONTROL MS-A•WA MU-A•WA 1-1. COOL ( ) OPERATION 1. Thermostat control Thermostat is ON or OFF by difference between room temperature and set temperature Thermostat ON OFF Room temperature minus set temperature (Initial) Room temperature minus set temperature (During operation) -1.8 °F or more less than -1.8 °F -1.8 °F -1.3 °F 2. Indoor fan speed control Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat’s OFFON.
1. Thermostat control Thermostat is ON or OFF by difference between room temperature and set temperature. Thermostat ON OFF Room temperature minus set temperature (Initial) Room temperature minus set temperature (During operation) -1.8 °F or more less than -1.8 °F -1.8 °F -1.3 °F 2. Indoor fan speed control Indoor fan operates at the set speed by FAN SPEED CONTROL button. When thermostat OFF (compressor OFF), fan speed becomes Very Low. In AUTO the fan speed is as follows. Fan speed High Med.
1-3. AUTO VANE OPERATION 1. Horizontal vane ECONO COOL ( ) operation (ECONOmical operation) When ECONO COOL button is pressed in COOL mode, set temperature is automatically set 3.6 °F higher than that in COOL mode. Also the horizontal vane swings in various cycle according to the temperature of indoor heat exchanger (indoor coil thermistor). SWING operation makes you feel cooler than set temperature. So, even though the set temperature is higher than that in COOL mode, the air conditioner can keep comfort.
2 MSZ,MSY MICROPROCESSOR CONTROL MSZ-A•NA MSY-A•NA MSZ-FD•NA MSY-D•NA MSZ-D•NA 2-1. COOL ( MUZ-A•NA MUY-A•NA MUZ-FD•NA MUY-D•NA MUZ-D•NA ) OPERATION 1. Thermostat control Thermostat is ON or OFF by difference between room temperature and set temperature Thermostat ON OFF Room temperature minus set temperature (Initial) Room temperature minus set temperature (During operation) -1.8 °F or more less than -1.8 °F -1.8 °F -1.3 °F 2.
) OPERATION Set temperature and °F initial room temperature in dry mode 95 Set temperature is as shown on the right chart. The system for dry operation uses the same refrigerant circuit as the cooling circuit. The compressor and the indoor fan are controlled by the room temperature. By such controls, indoor flow amounts will be reduced in order to lower humidity without much room temperature decrease. 86 Set temperature 2-2. DRY ( 77 68 59 50 50 95 °F 59 68 77 86 Initial room temperature 1.
(2) Cold air prevention control MSZ-A09/12/15/17 MSZ-FD MSZ-D When the compressor is not operating, ( ) if the temperature of room temperature thermistor is less than 66 °F, the fan stops. ( ) if the temperature of room temperature thermistor is 66 °F or more and ( ) if the temperature of indoor coil themistor is less than 32 °F, the fan stops. ( ) if the temperature of indoor coil themistor is 32 °F or more, the fan operates at Very Low.
(2) Releasing conditions of defrosting Defrosting is released when any of the following conditions is satisfied: a) The defrost thermistor continues to read 50 °F or more (MUZ-A09/12 MUZ-D) / 41 °F or more (MUZ-A15/17 MUZ-FD) / 59 °F or more (MUZ-A24) for 30 seconds. b) Defrosting time has exceeded 10 minutes. c) Any other mode than HEAT mode is set during defrosting.
(2) Mode change In case of the following conditions, the operation mode is changed. COOL mode changes to HEAT mode when 15 minutes have passed with the room temperature 4 °F below the set temperature. HEAT mode changes to COOL mode when 15 minutes have passed with the room temperature 4 °F above the set temperature. In the other cases than the above conditions, the present operation mode is continued.
In swing operation of ECONO COOL operation mode, the initial air flow direction is adjusted to “Horizontal”. According to the temperature of indoor coil thermistor RT12 at starting of this operation, next downward blow time is decided. Then when the downward blow has been finished, next horizontal blow time is decided. For initial 10 minutes the swing operation is performed in table G~H for quick cooling.
MUZ-A24 MUY-A24 MUZ-D MUY-D REACTOR POWER SUPPLY NOISE FILTER CIRCUIT P RESISTOR PFC + SMOOTHING CAPACITOR V N RELAY CURRENT TRANSFORMER U U W IPM V MS 3~ W COMPRESSOR Function of main parts NAME FUNCTION INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM. CURRENT TRANSFORMER It measures the current of the compressor motor. It measures the current of the main power supply circuit.
2-7-2. Outline of main power supply circuit MUZ-A09/12/15/17 MUY-A15/17 MUZ-FD 1. At the start of operation Main power supply circuit is formed when RELAY is turned ON at COMPRESSOR startup. To prevent rush current from running into the circuit when power supply is turned ON, RESISTOR is placed in sub circuit. 2. At normal operation When AC runs into POWER P.C. board, its external noise is eliminated in NOISE FILTER CIRCUIT. After noise is eliminated from AC, it is rectified to DC by DIODE MODULE 1.
4. Intelligent power module IPM consists of the following components · IGBT (x6) : Converts DC waveform to three-phase AC waveform and outputs it. · Drive Circuit : Drives transistors. · Protection circuit : Protects transistors from overcurrent. Since the above components are all integrated in IPM, IPM has a merit to make the control circuit simplify and miniaturize. 5. Elimination of electrical noise NOISE FILTER CIRCUIT, which is formed by *CMC COILS capacitors placed on the POWER P.C.
2-7-3. Sine wave control In these air conditioners, compressor equips brushless DC motor which doesn't have Hall element. In short, the motor is sensorless. However, it's necessary to locate the polar direction of rotor in order to drive brushless DC motor efficiently. The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced by unenergized stator.
2-8. OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT 1. Outline The operational frequency is as following: First, the target operational frequency is set based on the difference between the room temperature and the set temperature. Second, the target operational frequency is regulated by discharge temperature protection, high pressure protection, electric current protection and overload protection and also by the maximum/minimum frequency. 2. Maximum/minimum frequency in each operation mode.
2-9. EXPANSION VALVE CONTROL (LEV CONTROL) (1) Outline of LEV control The LEV basic control is comprised of setting LEV opening degree to the standard opening °F set for each operational frequency of the compressor. However, when any change in indoor/outdoor temperatures or other factors cause air conditioning load fluctuation, the LEV control also works to correct LEV opening degree based on discharge temperature (Shell temperature) of the compressor, developing the unit’s performance.
(2) Time chart Air conditioner OFF (thermostat off) Air conditioner ON LEV opening degree Positioning Opening degree is corrected according to discharge temperature.
(b) Reference value of LEV standard opening degree (pulse) Applied model MUZ-A09/12 MUZ-A15/17 MUY-A15/17 MUZ-A24 MUY-A24 MUZ-FD MUZ-D MUY-D COOL HEAT COOL HEAT COOL HEAT COOL HEAT COOL HEAT A 130 100 290 130 150 130 180 130 150 100 B 190 130 300 150 166 150 240 180 170 120 C 240 170 350 220 186 170 300 240 210 140 20 D 260 210 350 250 206 196 320 270 250 190 E 260 230 370 280 230 210 320 300 280 240 F 260 230 370 300 260 226 320 300 300 280
3 MXZ MICROPROCESSOR CONTROL MXZ-A•NA 3-1. INVERTER SYSTEM CONTROL 3-1-1. Inverter main power supply circuit REACTOR POWER SUPPLY NOISE FILTER CIRCUIT P RESISTOR PFC + SMOOTHING CAPACITOR V N RELAY CURRENT TRANSFORMER U U W IPM V MS 3~ W COMPRESSOR Function of main parts NAME FUNCTION INTELLIGENT POWER MODULE (IPM) It supplies three-phase AC power to compressor. SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to IPM.
3. Power factor improvement Booster coil reactor and PFC rectify AC to DC and control its voltage. In the motor drive system of sine wave control, power factor can be improved by reducing harmonics. PFC and reactor stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth. 4. Power transistor module IPM consists of the following components. · Power Transistors (x6) : Converts DC waveform to three-phase AC waveform and outputs it. · Drive Circuit : Drives transistors.
3-2. EXPANSION VALVE CONTROL (LEV CONTROL) Linear expansion valve (LEV) is controlled by “Thermostat ON” commands given from each unit. Indoor unit status Stop of all indoor unit LEV opening Opening before stop → 500 pulse in 15 minutes When outdoor unit is operating, COOL : 5 pulse (full closed) some indoor units stop and some HEAT :(MXZ-2A / 3A30NA) : 140 pulse (slightly opened) :(MXZ-3A30NA- 1 / 4A ) : 100 → 59 pulse operate.
MXZ-2A20NA/3A30NA The table below shows the role of Exclusive LEV and Receiver LEV in each operation mode.
Determination of LEV standard opening in each indoor unit • The standard opening is on the straight line, which connects an each standard point in the section where divided into seven according to the operation frequency of compressor as shown in the figure below. (LEV opening is controlled in proportion to the operation frequency.) NOTE: Opening is adjusted at the standard opening according to the indoor unit conditions.
MXZ-2A20NA- 1 Exclusive LEV Standard opening (pulse) LEV Opening (code) 1 2 3 4 5 6 7 8 9 10 COOL 120 130 136 146 156 160 170 180 190 200 HEAT 248 248 258 266 274 280 286 292 300 306 Difference in operation number Difference in capacity Code3,4 Code5,6 Code7,8 Code9,10 Code11,12 Code13,14 Code15or above 2 3 6 9 12 15 25 35 -20 3 6 9 52 55 65 75 30 COOL HEAT Receiver LEV Standard opening (pulse) LEV Opening (code) 1 2 3 4 5 6 7 8 9 10 COOL 140 150 160 170 180 190 200 200 200 200 HEAT 80 84 90 110 120 130
Discharge temperature COOL ● 2 DRY ● 2 HEAT ● ● — Each correction • (Each gas pipe temperature thermistor - Minimum gas pipe temperature thermistor) 1 ● • (Main indoor coil thermistor - Sub indoor coil thermistor) 1 Perform this, when number of operation units is 2 units or more. MXZ-2A20NA- 1 , MXZ-3A30NA- 1 and MXZ-4A36NA are excluded. 2 Correct the LEV opening by discharge temperature.
MXZ-3A30NA- 1 MXZ-4A36NA Target discharge temperature (°F) COOL Operation frequency of compressor (Hz) Minimum ~ 14 15 ~ 23 24 ~ 32 33 ~ 41 42 ~ 50 51 ~ 59 60 ~ 68 69 ~ 77 78 ~ 86 87 ~ Maximum HEAT 1 unit 2 units 3 units 95 107.6 120.2 136.4 149 154.4 158 167 167 167 131 131 136.4 140 149 154.4 158 163.4 167 176 134.6 134.6 145.4 149 158 163.4 167 176 179.6 179.6 Number of operating unit 4 units 1 unit (MXZ-4A36) 140 140 140 143.6 149 158 158 161.6 161.6 161.6 125.6 136.4 149 154.4 154.4 154.
b) Correct the LEV separately by temperature difference “ ∆RT” between main/sub indoor coil thermistor. ∆RT 7.2 10.8 ∆RT ∆RT < 10.8 ∆RT < 7.2 LEV opening correction (pulse) 2 1 1 In addition, decrease the target discharge temperature corresponding ∆RT. ∆ RT 10.8 ∆RT 7.2 ∆RT< 10.8 ∆RT < 7.2 Temperature to be decreased (°F) 18 9 9 3-3. OPERATIONAL FREQUENCY RANGE MXZ-2A20NA Number of operating unit 4 7 9,10 12 8 ~ 10 11 ~ 13 14 ~ 16 17 ~ 1 2 MXZ-2A20NA- Capacity code COOL (Hz) Min. Max.
MXZ-3A30NA- 1 MXZ-4A Number of operating unit 1 2 3 (MXZ-3A) 3 (MXZ-4A) 4 (MXZ-4A) Capacity code 4 7 9,10 12 8 ~ 10 11 ~ 13 14 ~ 16 17 ~ 12 ~ 12 ~ 16 ~ COOL (Hz) Min. Max. 25 58 25 58 25 71 25 80 25 80 25 80 25 80 25 80 25 80 25 90 25 90 DRY (Hz) 25 25 25 35 31 31 42 42 52 52 52 Min. 20 20 20 20 20 20 20 20 20 20 20 HEAT (Hz) Max. Defrost 70 58 70 58 80 58 80 58 80 58 80 58 80 58 80 58 80 58 103 58 113 58 3-4.
3-7. PRE-HEAT CONTROL MXZ-3A30NAMXZ-2A20NA- 1 1 MXZ-4A36NA The compressor is energized even while it is not operating. This is to generate heat at the winding to improve the compressor's start-up condition. Power ON OFF Compressor ON OFF Outside temperature 68 °F 30min. Pre-heat 30 min. 30 min. 30 min. 30 min. 30 min. 15 min. 30 min.15 min. 30 min. ON OFF Breaker ON Start operation Stop operation When outside temperature is above 68 °F 1.
3-9. DRY OPERATION 1. Thermostat control Thermostat is ON or OFF by difference between room temperature and set temperature. Thermostat ON OFF Room temperature minus set temperature (Initial) Room temperature minus set temperature (During operation) -1.8 °F or more less than -1.8 °F -1.8 °F -1.3 °F 2. Coil frost prevention Coil frost prevention is as same as COOL mode. (3-8.2.) 3-10. HEAT OPERATION 1.