SERVICE TECHNICAL GUIDE
Contents
1. DC voltage which has been stabilized in process is converted to 3 phase AC by INVERTER MODULE and supplied to COMPRESSOR amp CURRENT TRANSFORMER which is placed in the power supply circuit to COMPRESSOR is used to measure the value of phase current and locate the polar direction of rotor with algorithm PWM Pulse width modulation controls impressed voltage and frequency with those pieces of information 3 Purpose of PAM adoption PAM Pulse Amplitude Modulation has been adopted for the efficiency improvement and the adaptation to IEC harmonic cur rent emission standard Outline of simple partial switching method In conventional inverter models DIODE MODULE rectifies AC voltage to DC voltage SMOOTHING CAPACITOR makes its DC waveform smooth and INVERTER MODULE converts its DC voltage to imitated AC voltage again in order to drive the compressor motor However it has been difficult to meet IEC harmonic current emission standard by above circuit because harmonic gets generated in the input current waveform and power factor gets down The simple partial switching method with PAM which has been adopted this time places and utilizes BOOSTER CHOPPER CIRCUIT before rectifying AC voltage in the general passive method converter circuit As harmonic gets suppressed and the peak of waveform gets lower by adding BOOSTER CHOPPER CIRCUIT as mentioned above and by synchronizing the timing of switching with the zero cross point of waveform the in2. the fan operates at Very Low When the compressor is operating I ifthe temperature of indoor coil thermistor is 104 F 40 C or more the fan operates at set speed if the temperature of indoor coil thermistor is less than 104 F 40 C and 1 if heating operation starts after defrosting the fan stops ii if the temperature of room temperature thermistor is 66 F 19 C or less the fan stops iii if the temperature of room temperature thermistor is more than 66 F 19 C the fan operates at Very Low NOTE When 3 minutes MSZ HE09 12 18NA 4 minutes MSZ HE24NA have passed since the compressor started operation this control is released regardless of the temperature of room temperature thermistor and indoor coil thermistor 3 Warm air control When the following any condition of a c and the condition of are satisfied at the same time warm air control works Fan speed is used in MANUAL b When cold air prevention has been released c When defrosting has been finished When the temperature of indoor coil thermistor is less than 104 F 40 C When warm air control works the fan speed changes as follows to blow out warm air gradually Gradation of fan speed in initial MSZ HE09 12 15 18NA lt Time condition gt lt Indoor fan speed gt Less than 2 minutes Low 2 to 4 minutes Med More than 4 minutes High MSZ HE24NA lt Time condition gt lt Indoor fan sp
3. H for more cooling The air conditioner repeats the swing operation in various cycle as follows Temperature of indoor coil thermistor F C Downward blow time Horizontal blow time second second 59 15 or less 2 23 59 15 to 63 17 5 20 63 17 to 64 18 8 17 64 18 to 68 20 11 14 68 20 to 70 21 14 70 21 to 72 22 17 72 22 to 75 24 20 more than 75 24 1 7 INVERTER SYSTEM CONTROL 1 7 1 Inverter main power supply circuit MUZ HE09 12 15 18 POWER SUPPLY 23 DIODE MODULE1 INVERTER MODULE r POWER TRANSISTOR p od SWITCHING Function of main parts NAME FUNCTION CURRENT TRANSFORMER COMPRESSOR INVERTER MODULE It supplies 3 phase AC power to compressor SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to INVERTER MODULE CURRENT TRANSFORMER It measures the current of the compressor motor DIODE MODULE 1 It converts the AC voltage to DC voltage RESISTOR It absorbs the rush current not to run into the main power supply circuit when the power is turned ON RELAY It keeps the RESISTOR which restricts rush current short circuited while the compressor is operating DIODE MODULE 2 BOOSTER CHOPPER SWITCHING POWER TRANSISTOR CIRCUIT REACTOR OBT49 It improves power factor It
4. controls the bus bar voltage MUZ HE24 CURRENT TRANSFORMER REACTOR POWER RESISTOR SUPPLY RELAY POWER FACTOR INVERTER COMPRESSOR CORRECTION MODULE MODULE Function of main parts NAME FUNCTION INVERTER MODULE It supplies 3 phase AC power to compressor SMOOTHING CAPACITOR It stabilizes the DC voltage and supplies it to INVERTER MODULE CURRENT TRANSFORMER It measures the current of the compressor motor REACTOR It rectifies AC controls its voltage and improves the power factor of power sup POWER FACTOR CORRECTION MODULE ply It absorbs the rush current not to run into the main power supply circuit when the RESISTOR power is turned ON RELAY It keeps the RESISTOR which restricts rush current short circuited while the compressor is operating 1 7 2 Outline of main power supply circuit MUZ HE09 12 15 18 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 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 DC voltage to which AC has been rectified by process is stabilized by SMOOTHING CAPACITOR and supplied to IN VERTER MODULE
5. minutes after compressor starts NOTE When 2 or more indoor units are operated with multi outdoor unit even if any indoor unit turns thermostat OFF this control does not work in the indoor unit 2 ECONO COOL 2 operation ECONOmical operation When ECONO COOL button is pressed in COOL mode set temperature is automatically set 3 6 F 2 C 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 As a result energy can be saved To cancel this operation select a different mode or press one of the following buttons in ECONO COOL operation ECONO COOL or VANE CONTROL button OBT49 d lt SWING operation gt 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 Also after 10 minutes when the difference of set temperature and room temperature is more than 3 6 F 2 C the swing operation is performed in table D
6. temperature operation mode lt Operation gt 1 Outdoor fan control The outdoor fan rotational speed slows down to maintain sufficient cooling capacity NOTE Even when the unit is in the thermostat off status under the low outside temperature operation mode the out door fan rotation does not stop 2 Dew drop prevention When the ambient temperature thermistor reads 14 F 10 C or less the set temperature is different depending on the models as coil frost or dew drop from indoor unit may occur the compressor turns OFF with the outdoor fan OFF for prevention of them 3 Outdoor temperature detecting control To detect the exact outdoor temperature in this mode the compressor turns OFF but the outdoor fan stays ON for 3 minutes once 1 hour If the outdoor temperature rises over about 64 F 18 C the unit goes back to the normal COOL mode If the outside temperature stays below about 64 F 18 C the unit continues to run in the low outside temperature operation mode xOther protections work as well as in the normal COOL mode OBT49 3 1 2 DRY OPERATION reri ni in dry mode Set temperature is as shown on the right chart 9599 The system for dry operation uses the same refrigerant circuit as the cooling circuit 5 86 30 The compressor and the indoor fan are controlled by the room tem perature S US By such controls indoor flow amounts will be reduced in
7. unenergized stator Therefore it is necessary to have a certain period of time in which the stator is being unenergized for the rotor position detection when the voltage of supplied power is impressed So the motor has been driven by square wave control the conventional motor drive system which energizes the motor only when the range of electrical angle is within 120 because it is forced to be unenergized within 30 at start amp end of one heap in one waveform cycle 180 when the voltage is impressed However torque pulsation occurs at rotation in this method when the current carrying phases are switched over to other phases in sequence Therefore sine wave control system is adopted for these air conditioners because it can make the phase to phase current waveform smoother sine wave in order to drive the motor more efficiently and smoothly 1 7 4 Characteristics of sine wave control in case of brushless DC motor e Although ordinary 3 phase induction motor requires energy to excite the magnetic field of rotor brushless DC motor does not need it So higher efficiency and torque are provided This control provides the most efficient waveform corresponding to the rotational speed of compressor motor e The rotation can be set to higher compared to the conventional motor drive system So the time in which air conditioner can be operated with less energy is longer than conventional models This can save annual electric consumption Compared to s
8. 100 8310 JAPAN Copyright 2014 MITSUBISHI ELECTRIC CORPORATION Distributed in Feb 2014 No OBT49 New publication effective Feb 2014 Made in Japan Specifications are subject to change without notice
9. 5 minutes have passed with the room temperature 2 4 F 1 2 C above the set temperature In the other cases than the above conditions the present operation mode is continued NOTE41 Mode selection is performed when multi standby refer to NOTE2 is released and the unit starts operation with ON timer NOTE2 When two or more indoor units are operating simultaneously the indoor unit which is operating in AUTO i1 might not be able to change over the operating mode COOL lt HEAT and becomes the standby state 3 Indoor fan control Vane control As the indoor fan speed and the horizontal vane position depend on the selected operation mode when the operation mode changes over they change to the exclusive ones 1 5 OUTDOOR FAN MOTOR CONTROL Fan speed is switched according to the compressor frequency Fan speed Relation between compressor frequency and fan speed High 75 Applied model Compressor frequency Hz Down Up MUZ HE09 39 54 Low MUZ HE12 15 18 33 44 MUZ HE24 33 43 Min Compressor frequency Max 1 6 AUTO VANE OPERATION 1 Horizontal vane 1 Cold air prevention in HEAT operation When any of the following conditions occur in HEAT operation the vane angle changes to Horizontal position automati cally to prevent cold air blowing on users Compressor is not operating Defrosting is performed Indoor coil thermistor temperature does not exceed 102 F 39 C within about 3
10. Changes for the Better MITSUBISHI ELECTRIC SPLIT TYPE AIR CONDITIONERS No OBT49 SERVICE TECHNICAL GUIDE Models MSZ HEO9NA MUZ HE0O9NA MSZ HE12NA MUZ HE12NA MSZ HE15NA MUZ HE15NA MSZ HE18NA MUZ HE18NA MSZ HE24NA MUZ HE24NA CONTENTS CONFIDENTIAL FOR INTERNAL USE ONLY etc 1 MSZ MICROPROCESSOR 3 Indoor unit models Outdoor unit models MSZ HE09NA MUZ HE09NA MSZ HE12NA MUZ HE12NA MSZ HE15NA MUZ HE15NA MSZ HE18NA MUZ HE18NA MSZ HE24NA MUZ HE24NA 1 1 COOL OPERATION S LEN 3 1 2 DRY OPERATION 4 1 3 4 1 4 AUTO CHANGE OVER T AUTO MODE OPERATION FLITE IET ERGO 7 1 5 OUTDOOR FAN MOTOR CONTROL SORRRRRONRSRERRRRERVRERRRERERSERSRARRR RESRRORRARRERREERROSZGRRSRERERESRERROSERSERSEERERREBRTRRERERRERRVER SENE 7 1 6 AUTO VANE OPERATION 7 1 7 INVERTER SYSTEM CONTROL 8 1 8 OPERATIONAL FREQUENCY CONTROL OF OUTDOOR UNIT E TEE TEE 12 1 9 EXPANSION VALVE CONTROL LEV CONTROL T A CTL T ETRE CECE RTT CROCCO PEPER ECC CLT 13 1 10 PRE HEAT CONTROL 15 49 2 MSZ MICROPROCESSOR CONTROL 1 1 COOL OPERATION 1 Thermostat control Thermostat turns ON or
11. FACTOR CORRECTION MODULE 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 POWER FACTOR CORRECTION MODULE and reactor stabilize the voltage of DC supplied to inverter circuit and make its waveform smooth OBT49 is 4 Inverter module INVERTER MODULE consists of the following components IGBT x6 Converts DC waveform to 3 phase AC waveform and outputs it Drive Circuit Drives transistors Protection circuit Protects transistors from over current Since the above components are all integrated in INVERTER MODULE INVERTER MODULE has a merit to make the con trol circuit simplified and miniaturized 5 Elimination of electrical noise NOISE FILTER CIRCUIT which is formed by CMC COILS NMC COILS and capacitors eliminates electrical noise of AC power that is supplied to main power supply circuit This circuit also prevents the electrical noise generated in the inverter circuit from leaking out CMC COILS Common mode choke coils NMC COILS Normal mode choke coils 1 7 3 Sine wave control In these air conditioners compressor equips brushless DC motor which does not have Hall element In short the motor is sensorless However it is necessary to locate the polar direction of rotor in order to drive brushless DC mo tor efficiently The general detection method of the polar direction for such a DC motor is to locate it from the voltage induced by
12. OFF by the difference between room temperature and set temperature Room temperature minus Room temperature minus Thermostat set temperature Initial set temperature During operation ON 1 35 F 0 75 C or more OFF less than 1 8 F 1 C E 2 25 F 1 35 1 25 C 0 75 C 2 Indoor fan speed control Indoor fan operates continuously at the set speed by FAN SPEED CONTROL button regardless of the thermostat s OFF ON In AUTO the fan speed is as follows Room temperature minus Room temperature minus Fan speed set temperature Initial set temperature During operation High 3 15 F 1 75 C or more Med between 1 8 and 3 15 F Low less than 1 8 F 1 C 3 C 1 8F 3 15 F 1 1 75 C 3 Coil frost prevention The compressor operational frequency is controlled to prevent the temperature of indoor heat exchanger from falling exces sively The compressor is turned OFF for 5 minutes when the temperature of indoor coil thermistor continues 37 F 3 C or less for 5 minutes or more The indoor fan maintains the actual speed of the moment 4 Low outside temperature operation If the outside temperature falls to 64 F 18 C or less during operation in COOL mode the unit will switch to the low outside
13. TIONAL 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 Operational frequency Hz Applied model COOL HEAT DRY Minimum Maximum Minimum Maximum Minimum Maximum MUZ HE09 28 93 30 105 28 48 MUZ HE12 20 98 30 98 30 55 MUZ HE15 15 90 15 102 15 54 MUZ HE18 15 98 15 105 15 83 MUZ HE24 26 26 124 26 x The operation frequency in COOL mode is restricted by the upper limit frequency after 1 hour or 0 5 1 hour as shown below for dew prevention It is rated frequency or less Maximum frequency Upper limit frequenc 3 x or Rated frequency or less 0 5 1 hour lt lt Time OBT49 1e 1 9 EXPANSION VALVE CONTROL LEV 1 Outline of LEV control CONTROL The LEV basic control is comprised of setting LEV opening degree to the standard opening degrees set for each opera tional frequency of the compressor However when any change in indoor outdoor temperatures or other factors cause air conditioning load fluctuati
14. e NOISE FILTER CIRCUIT which is formed by CMC COILS and capacitors eliminates electrical noise of AC power that is supplied to main power supply circuit This circuit also prevents the electrical noise generated in the inverter circuit from leaking out CMC COILS Common mode choke coils MUZ HE24 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 noise filter P C board its external noise is eliminated in NOISE FILTER CIRCUIT After noise is eliminated from AC it is rectified to DC by REACTOR and POWER FACTOR CORRECTION MODULE If the operating frequency becomes 25 Hz or more DC voltage rises to 370 V DC voltage to which has AC been rectified by process is stabilized by SMOOTHING CAPACITOR and supplied to IN VERTER MODULE The DC Bus voltage which has been stabilized in process is converted to 3 phase AC by INVERTER MODULE and supplied to COMPRESSOR amp CURRENT TRANSFORMER which is placed in the power supply circuit to COMPRESSOR is used to measure the value of phase current and locate the polar direction of rotor with algorithm PWM Pulse width modulation controls impressed voltage and frequency with those pieces of information 3 Power factor improvement Booster coil reactor and POWER
15. eed gt Less than 4 minutes Low 4 to 8 minutes Med More than 8 minutes High The upper limit of the fan speed in MANUAL is the set speed When the temperature of indoor coil thermistor has been 104 F 40 C or more or when the set speed has been changed this control is released and the fan speed is the set speed 3 Overload starting When the room temperature thermistor reads 64 F 18 C or more the compressor runs with its maximum frequency regu lated for 10 minutes after the start up 4 Defrosting 1 Starting conditions of defrosting When the following conditions a c are satisfied the defrosting starts a The defrost thermistor reads about 30 2 F 1 C or less b The cumulative operation time of the compressor has reached any of the set values defrost interval 40 150 min utes c More than 5 minutes have passed since the start up of the compressor x The defrost interval is decided by the previous defrosting time The next defrost interval extends or shortens 0 20 minutes compared with the previous defrost interval 2 Releasing conditions of defrosting Defrosting is released when any one of the following conditions is satisfied a The defrost thermistor continues to read Defrost finish temperature for 30 seconds Refer to CHANGE IN DEFROST SETTING of SERVICE FUNCTIONS in OUTDOOR UNIT SERVICE MANUAL b Defrosting time has exceeded 10 minutes c Any other mode than HEAT m
16. eration the indoor coil thermistors main and sub sense temperature ununiformity super heat at the heat exchanger and when temperature difference develops the indoor coil thermistors adjust LEV opening degree to get approximate 18 F 10 C lower temperature than the target temperature in the table above thus diminishing super heat MUZ HE09 MUZ HE12 MUZ HE15 MUZ HE18 MUZ HE24 OBT49 n 1 10 PRE HEAT CONTROL 1 Outline Compressor is energized to improve the start up of compressor at a low outside temperature even when compressor is stopped 2 Pre heat control ON i i i OFF p ON Red INR i i ee S Pre heat control oFF 3 aes se Outside temperature 68 F 35 30 minutes 1 hour Pre heat control ON condition 1 Compressor is not operating However pre heat control is still OFF for 30 minutes after compressor is stopped regardless of the outside temperature 2 Outside temperature is 68 F 20 C or below Outside temperature is monitored hourly and when outside temperature is 68 F 20 C or below pre heat control is turned ON When pre heat control is turned ON compressor is energized about 50 W 40 60 W Compressor and fan are not operated OBT49 9 MITSUBISHI ELECTRIC CORPORATION HEAD OFFICE TOKYO BLDG 2 7 3 MARUNOUCHI CHIYODA KU TOKYO
17. ode is set during defrosting OBT49 Time chart of defrosting in HEAT mode reverse type lt Indoor unit gt Horizontal vane Indoor fan set position horizontal temperature of indoor coil thermistor lt 102 F 39 C horizontal set speed Very Low temperature of indoor coil thermistor gt 64 F lt Outdoor unit gt Compressor normal Outdoor fan OBT49 40 seconds mM gt om 9 ON seconds i 30 seconds 5 seconds OFF Maximum frequency 18 C 40 seconds set position set speed seconds 5 seconds gt ON 1 4 AUTO CHANGE OVER AUTO MODE OPERATION Once desired temperature is set unit operation is switched automatically between COOL and HEAT operation 1 Mode selection 1 Initial mode At first indoor unit operates only indoor fan with outdoor unit OFF for 3 minutes to detect present room temperature Following the conditions below operation mode is selected If the room temperature thermistor reads more than set temperature COOL mode is selected Q If the room temperature thermistor reads set temperature or less HEAT mode is selected 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 2 4 F 1 2 C below the set temperature HEAT mode changes to COOL mode when 1
18. on the LEV control also works to correct LEV opening degree based on discharge tempera ture Shell temperature of the compressor developing the unit s performance Control range Minimum 54 pulses Maximum 500 pulses Actuating speed Open 40 pulses second Close 90 pulses second Opening degree adjustment Standard specification LEV opening degree is always adjusted in opening direction When reducing the opening degree LEV is once over closed and then adjusted to the proper degree by opening Unit OFF LEV remains at maximum opening degree reaches maximum opening degree approximate in 15 minutes after compressor stops Remote controller ON LEV is positioned First full closed at zero pulses and then positioned During 1 to 15 minutes after compressor starts LEV is fixed to standard opening degree according to operational frequency of compressor More than about 15 minutes have passed since compressor start up General operation LEV opening degree is corrected to get target discharge temperature of com pressor For lower discharge temperature than target temperature LEV is corrected in closing direction For higher discharge temperature than target temperature LEV is corrected in opening direction x It may take more than 30 minutes to reach target temperature depending on operating conditions Thermostat OFF Thermostat ON LEV is adjusted to exclusive opening degree fo
19. order to E lower humidity without much room temperature decrease 8 Ge 20 E L o i 3 E 59 15 1 Thermostat control iE 88 pua a amp Thermostat turns ON or OFF by the difference between room temperature Initial room temperature F C and set temperature Room temperature minus Room temperature minus Thermostat set temperature Initial set temperature During operation ON 3 15 F 1 75 C or more OFF less than 3 6 F 2 C Ae 4 05 F 3 15 2 25 C 1 75 2 Indoor fan speed control Indoor fan operates at the set speed by FAN SPEED CONTROL button When the thermostat turns OFF compressor OFF fan speed becomes Very Low In AUTO the fan speed is as follows Room temperature minus Room temperature minus Fan speed set temperature Initial set temperature During operation High 3 15 F 1 75 C or more Med between 1 8 and 3 15 F 1 35 Low less than 1 8 F 1 C 2 5 1 8 F 3 15 1 1 75 3 Coil frost prevention Coil frost prevention works the same way as that in COOL mode 1 1 3 The indoor fan maintains the actual speed of the moment However when coil frost prevention works while the compressor is not operating its speed becomes the set speed 4 Low ou
20. put current waveform can be improved and the requirement of IEC harmonic current emission standard can be satisfied Since the switching synchronized with the zero cross point this simple partial switching method has the feature of lower en ergy loss compared to active filter method In addition output and efficiency is enhanced by combining with vector controlled inverter in order to boost the voltage of power supplied to INVERTER MODULE OBT49 Input current waveform without PAM Input current waveform with PAM Due to the time of no electricity Owing to the increase of energized time Power factor gets worse Power factor gets better Harmonic gets increased Harmonic gets suppressed Input voltage Input current Release of energy stored in L Peak gets down P ij i Energized time is extended by optimization of L inductance No electricity runs into diode module because the voltage at both sides of smoothing capacitor is higher than input voltage Compulsory energizing by switching 4 Inverter module INVERTER MODULE consists of the following components IGBT x6 Converts DC waveform to 3 phase AC waveform and outputs it Drive Circuit Drives transistors Protection circuit Protects transistors from overcurrent Since the above components are all integrated in INVERTER MODULE INVERTER MODULE has a merit to make the con trol circuit simplify and miniaturize 5 Elimination of electrical nois
21. quare wave control the torque pulsation is reduced at rotation so that the motor operates more quietly e Since the response and efficiency of motor are enhanced in sine wave control finer adjustment can be provided DC Motor AC Motor Rotor Permanent magnet is embedded It is excited by magnetic field of stator Rotor Position Signal Necessary Unnecessary X In brushless DC motor permanent magnet is embedded in the rotor Therefore it does not require energy to excite the rotor like AC motor does However it is necessary to control the frequency of 3 phase AC current supplied to the stator accord ing to the polar direction of magnet embedded in the rotor so as to drive the motor efficiently Controlling 3 phase AC current frequency also means controlling the timing to switch the polarity of stator Therefore the polar direction of rotor needs to be detected 1 7 5 Control Method of Rotational speed Sine wave control makes the current transformers conduct real time detection of the value of the current running into the mo tor locates the rotor position from the detected value and decides if voltage should be impressed and if frequency should be changed Compared to the conventional control and rotor position detection method sine wave control can provide finer adjustment of the voltage of supplied power The value of the current running into the motor is determined by each motor characteristic OBT49 1 8 OPERA
22. r thermostat OFF LEV is controlled in the same way as that after the compressor has started up Defrosting in HEAT mode 2 Time chart Air conditioner ON LEV is adjusted to open 500 pulses Air conditioner OFF thermostat off Positioning Opening degree is corrected according Ea to discharge o Standard temperature Commanded c opening Refer to 3 to open degree c 1 2 i o i gt i i i 2 i About 15 minutes Time gt 2 i 5 9 i 2 0 Patat 1 geo i 2a a5 co Lo 9o i amp i ON OFF Time OBT49 13 3 Control data 23 38 53 69 84 99 Hz MUZ HE24 30 50 70 90 110 130 Hz Other models Operational frequency of the compressor Target discharge temperature Ww a Reference value of target discharge temperature COOL HEAT F C Applied model A B D E F 126 52 136 58 149 65 153 67 158 70 160 71 109 43 122 50 131 55 138 59 149 65 156 69 127 53 140 60 147 64 153 67 162 72 169 76 109 43 124 51 138 59 156 69 167 75 176 80 120 49 131 55 147 64 153 67 162 72 169 76 109 43 124 51 138 59 156 69 167 75 176 80 135 57 140 60 144 62 153 67 165 74 178 81 140 60 149 65 158 70 167 75 167 75 167 75 131 55 142 61 151 66 162 72 171 77 178 81 115 46 133 56 151 66 167 75 181 83 187 86 In COOL op
23. tside temperature operation Low outside temperature operation works the same way as that in COOL mode 1 1 4 1 3 HEAT i OPERATION 1 Thermostat control Thermostat turns ON or OFF by difference between room temperature and set temperature Room temperature minus Room temperature minus Thermostat set temperature Initial set temperature During operation less than 1 8 F 1 C ORF 2 5 9555 5 1 8 F 1 C or more I t 2 Indoor fan speed control 1 Indoor fan operates at the set speed by FAN SPEED CONTROL button In Auto the fan speed is as follows Set temperature minus Set temperature minus room Fan speed room temperature Initial temperature During operation 36 F 7 2 F 3 6 2 or more 2C uo Med Between 0 45 and 3 6 F LOW Less than 0 45 F 0 25 C o 0 45 F 3 025 C 175 C OBT49 2 Cold air prevention control When the compressor is not operating 1 if the temperature of room temperature thermistor is less than 66 F 19 C the fan stops if the temperature of room temperature thermistor is 66 F 19 C or more and 1 if the temperature of indoor coil thermistor is less than 32 F 0 C the fan stops ii if the temperature of indoor coil thermistor is 32 F 0 or
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