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Specifications subject to change without notice.                                                                          

TABLE of CONTENTS

PAGE

SA\FETY CONSIDERATIONS...................................................... 1
INTRODUCTION............................................................................ 1
MODEL / SERIAL NUMBER NOMENCLATURES .................... 2
WIRING........................................................................................... 3
CONNECTION DIAGRAM............................................................ 3
WIRING DIAGRAMS..................................................................... 4
REFRIGERATION CYCLE DIAGRAM........................................ 8
REFRIGERANT LINES.................................................................. 9
SYSTEM EVACUATION AND CHARGING ............................... 10
SYSTEM VACUUM AND CHARGE ............................................ 10
ELECTRONIC FUNCTIONS ......................................................... 11
POINT CHECK FUNCTION .......................................................... 14
TROUBLESHOOTING................................................................... 16
DIAGNOSTIC GUIDES.................................................................. 17
DIAGNOSIS AND SOLUTION...................................................... 18
DISASSEMBLY INSTRUCTIONS SIZE 36.................................. 47
DISASSEMBLY INSTRUCTIONS SIZE 48-58 ............................ 53

SA\FETY CONSIDERATIONS

Installing, starting up, and servicing air-conditioning equipment can
be hazardous due to system pressures, electrical components, and
equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics should install,
start-up, and service this equipment.
Untrained personnel can perform basic maintenance functions such as
coil cleaning. All other operations should be performed by trained
service personnel.
When working on the equipment, observe precautions in the literature
and on tags, stickers, and labels attached to the equipment.
Follow all safety codes. Wear safety glasses and work gloves. Keep a
quenching cloth and fire extinguisher nearby when brazing. Use care
in handling, rigging, and setting bulky equipment.
Read this manual thoroughly and follow all warnings or cautions
included in the literature and attached to the unit. Consult local
building codes and National Electrical Code (NEC) for special
requirements. Recognize safety information. This is the safety-alert
symbol 

. When you see this symbol on the unit and in instructions

or manuals, be alert to the potential for personal injury. Understand
these signal words: 

DANGER

WARNING

, and 

CAUTION

These words are used with the safety-alert symbol. 

DANGER 

identifies the most serious hazards which 

will 

result in severe personal 

injury or death. 

WARNING 

signifies hazards which 

could

 result in 

personal injury or death. 

CAUTION 

is used to identify unsafe 

practices which 

may 

result in minor personal injury or product and 

property damage. 

NOTE 

is used to highlight suggestions which 

will

 

result in enhanced installation, reliability, or operation.

INTRODUCTION

This service manual provides the necessary information to service, 
repair, and maintain the 

38MBR

 family of heat pumps. Use the 

“TABLE of CONTENTS” on page 1 to locate a desired topic. For 
detailed information regarding product specifications refer to product 
data documentation.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Before installing, modifying, or servicing system, main electrical 

disconnect switch must be in the OFF position. There may be more than 1 

disconnect switch.
Lock out and tag switch with a suitable warning label.

WARNING

EXPLOSION HAZARD

Failure to follow this warning could result in 
death, serious personal injury, and/or property 
damage. Never use air or gases containing oxygen 
for leak testing or operating refrigerant 
compressors. Pressurized mixtures of air or gases 
containing oxygen can lead to an explosion.

WARNING

EQUIPMENT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper
operation.
Do not bury more than 36 in. (914 mm) of refrigerant pipe in the ground. 
If any section of pipe is buried, there must be a 6 in. (152 mm) vertical rise 
to the valve connections on the outdoor units. If more than the 
recommended length is buried, refrigerant may migrate to the cooler 
buried section during extended periods of system shutdown. This causes 
refrigerant slugging and could possibly damage the compressor at start-up.

CAUTION

Service Manual

38MBR

Outdoor Unit Single Zone Ductless System 

   Sizes 36 to 58

Summary of Contents for 38MBR series

Page 1: ...the safety alert symbol DANGER identifies the most serious hazards which will result in severe personal injury or death WARNING signifies hazards which could result in personal injury or death CAUTIO...

Page 2: ...8MBRQ58A 3 OUTDOOR UNIT 38 MB R Q 36 A 3 38 OUTDOOR UNIT MB MODEL VOLTAGE 3 208 230 1 60 UNIT TYPE R OUTDOOR UNIT MAXIMUM NUMBER OF FAN COIL UNITS THAT CAN BE CONNECTED TO THE OUTDOOR UNIT A 1 1 NOT U...

Page 3: ...unication wire from the outdoor unit to the indoor unit Please use a separate shielded 16GA stranded control wire CONNECTION DIAGRAM Fig 1 Connection Diagram NOTES 1 Do not use thermostat wire for any...

Page 4: ...5VDC Discharge Temperature Sensor CN8 Input Pin3 Pin4 5VDC Pin2 0VDC Pin1 Pin5 0 5VDC T3 T4 CN9 Input Pin2 Pin4 0VDC Pin1 Pin3 0 5VDC H L Pressure Switch CN20 Output Pin1 Pin4 Pulse waveform 0 12VDC P...

Page 5: ...N55 Output Pin1 12VDC Pin2 5VDC Pin3 EARTH CN19 Pin1 Pin3 Connect to FAN voltage among phases 0 200VAC U V W Connect to compressor voltage among phases 0 200VAC CN51 CN52 CN51 EARTH CN52 EARTH Output...

Page 6: ...the H L pressure switch CN15 Output Pin1 Pin4 Pulse waveform 0 12VDC Pin5 Pin6 12VDC EEV CN6 Output Pin1 Pin6 Pulse waveform 0 5VDC Pin7 Pin9 0VDC Pin8 0 5VDC Pin10 5VDC IPM PFC BOARD MAIN BOARD WIRIN...

Page 7: ...380VDC Pin4 0 15VDC Pin5 0 5 6VDC Pin6 Pulse waveform 0 15VDC OUTDOOR UNIT DC MOTOR DRIVER BOARD CODE PART NAME CON1 Output Pin1 Pin2 High voltage 224 380VDC CN1 Input Pin4 Pulse waveform 0 15VDC Pin3...

Page 8: ...gerant Cycle Diagram LIQUID SIDE GAS SIDE HEAT EXCHANGE EVAPORATOR HEAT EXCHANGE CONDENSER Compressor 2 WAY VALVE 3 WAY VALVE 4 WAY VALVE COOLING HEATING T2B Evaporator temp sensor outlet T1 Room temp...

Page 9: ...T Both refrigerant lines must be insulated separately Table 9 displays the following maximum lengths allowed Table 9 Piping and Refrigerant The charge amount listed in Table 9 is for piping runs up to...

Page 10: ...tem is free of air and liquid water see Fig 7 Fig 7 Deep Vacuum Graph Triple Evacuation Method The triple evacuation method should be used Refer to Fig 8 and proceed as follows 1 Pump system down to 5...

Page 11: ...any of these protections engage the corresponding code displays on the indoor unit and the unit stops working Indoor Fan Delayed Open Function When the unit starts up the louver is active immediately...

Page 12: ..._ADD E DC_FAN_SSLOW_SPD_ADD 28 82 4 F 19 66 2 F 17 62 6 F 26 78 8 F 25 77 F 23 73 4 F 22 71 6 F 20 69 F A B C D E ADD DD D D D D D D D D D D D _A A A AD D D D D D D DD D D _ADD DD D D D D DD D D D D P...

Page 13: ...nd designs without notice and without obligations 13 Defrosting Mode If any one of the following conditions are met AC enters the DEFROSTING mode After the compressor starts and continues to run mark...

Page 14: ...failure the module memorizes the setting conditions before the power failure The unit resumes the previous operation setting not including sleep function automatically after 3 minutes when power retur...

Page 15: ...0 101 109 b0 b1 b9 110 111 119 c0 c1 c9 120 121 129 d0 d1 d9 130 131 139 E0 E1 E9 140 141 149 F0 F1 F9 150 151 159 Indoor fan speed Outdoor fan speed 0 OFF 1 2 3 4 Low speed Medium speed High speed Tu...

Page 16: ...tic codes for the indoor and outdoor units are listed in the following pages Problems may occur that are not covered by a diagnostic code but are covered by the diagnostic flow charts These problems a...

Page 17: ...rvice Manual 10 times O F9 Cassette optional lift panel not closed Refer to Indoor Unit Service Manual 1 time P0 Inverter module IPM malfunction Page 28 2 times P1 Over voltage or under voltage protec...

Page 18: ...utdoor fan speed malfunction F5 Page 25 8 Inverter module IPM malfunction P0 Page 27 9 Over voltage or under voltage protection P1 Page 31 10 Compressor top high temperature protection OLP P2 Page 32...

Page 19: ...ator The display value is a hex number For ex the digital display tube displays 2A then Bit5 1 Bit3 1 Bit1 1 It represents the frequency limit caused by T4 T3 and current Bit6 Frequency limit caused b...

Page 20: ...rased and reprogrammed using a pulsed voltage For the location of the EEPROM chip refer to the Fig 18 Fig 18 Outdoor PCB Figure 18 is for illustration purposes only and may differ from your actual uni...

Page 21: ...t rise is detected by checking the specified current detection circuit Supposed Causes Power supply problems System blockage PCB faulty Wiring mistake Compressor malfunction Clear the blockage Stop th...

Page 22: ...t receive feedback from indoor unit for 120 seconds Supposed Causes Wiring mistake Faulty indoor or outdoor PCB E1 displayed Is there any interference such as too many lamps or powertransformers Or is...

Page 23: ...hen the AC is running normally the voltage moves alternatively between 50V to 50V If the outdoor unit has a malfunction the voltage moves alternatively with a positive value If the indoor unit has a m...

Page 24: ...er on and when the unit is in standby measure the voltage of pin 1 pin3 pin4 pin3 in the fan motor connector If the value of the voltage is not in the range showing in the table below the PCB has an i...

Page 25: ...egisters below 200RPM or over 1500RPM for an extended period of time the unit stops and the LED displays the failure F5 Supposed Causes Wiring mistake Faulty fan assembly Faulty fan motor Faulty PCB Y...

Page 26: ...ing Fig 22 Test Error Code E4 E5 F1 F2 F3 Malfunction decision conditions If the sampling voltage is lower than 0 06V or higher than 4 94V the LED displays the failure Supposed Causes Wiring mistake S...

Page 27: ...after the compressor starts up if T2 Tcool 35 6 F Tcool 2 C does not keep continuous 4 seconds and this situation happens 3 times the display area shows EC and AC turns off Supposed Causes T2 sensor f...

Page 28: ...ferences input voltage N references output voltage Error Code PO Malfunction decision conditions When the voltage signal that IPM sends to the compressor drive chip is abnormal the LED displays PO and...

Page 29: ...38MBR Service Manual Manufacturer reserves the right to change at any time specifications and designs without notice and without obligations 29 Fig 23 P U Fig 24 P V...

Page 30: ...38MBR Service Manual Manufacturer reserves the right to change at any time specifications and designs without notice and without obligations 30 Fig 25 P W Fig 26 P N...

Page 31: ...tage or Too Low Voltage Protection Diagnosis and Solution P1 Troubleshooting Fig 27 Test Error Code P1 Malfunction decision conditions An abnormal current rise is detected by checking the specified cu...

Page 32: ...Causes Power supply problems System leakage or block PCB faulty Power OFF Wait 10 minutes and re start the unit No Yes Check the compressor temperature Is it within acceptable parameters Yes Check th...

Page 33: ...al detection voltage detection compressor rotation speed signal detection and so on Supposed Causes Wiring mistake IPM malfunction Outdoor fan assembly fault Compressor malfunction Outdoor PCB faulty...

Page 34: ...Sensor Malfunction Diagnosis and Solution P7 Troubleshooting Error Code P7 Malfunction decision conditions If the sampling voltage is lower than 0 06V or higher than 4 94V the LED displays a failure...

Page 35: ...CB J0 displayed Evaporator high temperature protec on Is the compressor opera ng Is the connec on between T2 and the PCB in working order Has T2 and T2B been reversed Correct the connec on No Is the o...

Page 36: ...tween the temperature sensor and the PCB in working order Correct the connec on No Is the outdoor ambient temp higher than 122 F 50 C Yes Stop the unit Yes No Is the resistance of the condenser temp s...

Page 37: ...mperature sensor Faulty outdoor PCB J2 displayed Temperature protec on of condenser discharge Is the compressor temperature higher than 239 F 115 C Stop the leak and add refrigerant Are the compressor...

Page 38: ...Causes Faulty wiring Faulty IPM board Faulty outdoor fan assembly Compressor malfunction Faulty outdoor PCB J3 displayed PFC module protec on Check whether the connec ng line between the main board a...

Page 39: ...Faulty IPM Outdoor board Faulty Main Outdoor board Faulty rectifier J4 displayed Communica on error between the outdoor main chip and the compressor drive board Is there at least one LED in the compr...

Page 40: ...ol board No Is the high pressure protector broken Yes Method Disconnect the plug Measure the high pressure protector resistance If the protector is normal the value is 0 Does the problem s exist Repla...

Page 41: ...ressure protector broken Yes Method Disconnect the plug Measure the low pressure protector resistance If the protector is normal the value is 0 Does the problem s exist Replace the high pressure prote...

Page 42: ...L and N wiring is correct Measure whether the outdoor terminal voltage is normal Verify the wires are well connected No Reconnect well Measure whether the voltage between L and N is normal Yes Yes Re...

Page 43: ...s Check Temperature sensor checking Disconnect the temperature sensor from PCB measure the resistance value with a tester Temperature sensors Room temp T1 sensor Indoor coil temp T2 sensor Outdoor coi...

Page 44: ...tinuity Check Turn off the power let the large capacity electrolytic capacitors discharge completely and dismount the IPM Use a digital tester to measure the resistance between P and UVWN UVW and N PO...

Page 45: ...TEMP 75 23 89 85 29 44 95 35 105 40 56 115 46 11 BAR 70 8 2 7 8 8 1 8 6 10 1 BAR 75 8 6 8 3 8 7 9 1 10 7 BAR 80 9 3 8 9 9 1 9 6 11 2 PSI 70 119 113 117 125 147 PSI 75 124 120 126 132 155 PSI 80 135 1...

Page 46: ...3 89 47 8 33 37 2 78 27 2 78 17 8 33 BAR 55 30 3 28 5 25 3 22 8 20 8 BAR 65 32 5 30 0 26 6 25 4 23 3 BAR 75 33 8 31 5 27 8 26 3 24 9 PSI 55 439 413 367 330 302 PSI 65 471 435 386 368 339 PSI 75 489 45...

Page 47: ...handle 3 screws No Part name Procedures Remarks 1 Panel plate Remove the panel plate 1 Stop the air conditioner and turn off the power breaker 2 Remove the big handle first then remove the top cover 7...

Page 48: ...ithout obligations 48 DISASSEMBLY INSTRUCTIONS SIZE 36 CONT 1 Use procedure 1 to remove the panel plate 2 Remove the nut securing the fan then remove the fan Unfix the hooks and remove the screws Next...

Page 49: ...ithout notice and without obligations 49 DISASSEMBLY INSTRUCTIONS SIZE 36 CONT 4 Disconnect the fan motor connector from the electronic control board 5 Remove the fan motor s screws 4 then remove the...

Page 50: ...SASSEMBLY INSTRUCTIONS SIZE 36 CONT 3 Electrical parts Remove the electrical parts 1 2 Pull out the two blue wires connected with the 4 way valve 3 Pull out the condenser coil temp sensor T3 connector...

Page 51: ...s without notice and without obligations 51 DISASSEMBLY INSTRUCTIONS SIZE 36 CONT 5 6 Remove the ground wires 7 Remove the wires 1 2 3 or L1 L2 S Next remove the electronic control box 6 7 5 4 4 Disco...

Page 52: ...crew then remove the coil 4 Detach the 4 way valve s and pipe s welded parts 5 Remove the 4 way valve assembly The picture of the 4 way may differ from your actual valve 5 Compressor Remove the compre...

Page 53: ...s 53 DISASSEMBLY INSTRUCTIONS SIZE 48 58 No Part name Procedures Remarks 1 Remove the fan assembly 1 Stop the air conditioner and turn off the power breaker 2 Remove the air outlet grille screws 8 3 R...

Page 54: ...FAN2 3p white from the DC motor driver board 8 Remove the fan motor after unfastening the securing screws 2 Panel plate Remove the panel plate 1 Remove the big handle screws 2 and the water collector...

Page 55: ...INSTRUCTIONS SIZE 48 58 CONT 3 Electrical parts Remove the electrical parts 1 Complete steps 5 6 in section 1 and section 2 2 Disconnect the fan motor connector 5p white from the IPM board 3 Disconnec...

Page 56: ...5 Disconnect the connectors and wires connected from the PCB and other parts Connectors CN8 Discharge temperature sensor 2p white CN12 Heatsink temperature sensor 2p red CN9 T3 T4 temperature sensor...

Page 57: ...and section 2 2 Extract the refrigerant gas 3 Remove the sound insultation material and crankcase heating cable 4 Remove the compressor terminal cover and disconnect the crankcase electric heater wire...

Page 58: ...The 4 way valve Remove the 4 way valve 1 Complete steps 5 6 of section 1 and section 2 2 Extract the refrigerant gas 3 Remove the electrical parts in section 3 4 Remove the coil screw and remove the...

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