Lennox MCB Series User manual

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Table of Contents
1. Safety Considerations ................................. 3
2. General Troubleshooting ............................ 4
2.1. Error Codes .......................................................4
2.2. Complaint Form .................................................5
2.3. Engineering Mode for System Query.................6
2.3.1. Engineering Mode Codes......................6
2.3.2. Engineering Mode Error Codes.............6
3. Quick Maintenance by Error Code ............. 7
4. Troubleshooting by Error Code.................. 8
4.1. TS01-IDU...........................................................8
4.2. TS01-ODU.........................................................8
4.3. TS02-S-INV .......................................................9
4.4. TS04-S-IDU .....................................................10
4.5. TS04-S-ODU ...................................................13
4.6. TS05-IDU.........................................................14
4.7. TS05-ODU.......................................................15
4.8. TS06-INV.........................................................16
4.9. TS07 ................................................................16
4.10. TS08-S.............................................................17
4.11. TS09-S.............................................................18
4.12. TS10-S.............................................................19
4.13. TS12-S.............................................................20
5. Check Procedures ..................................... 21
5.1. Temperature Sensor Check.............................21
5.2. Compressor Check..........................................21
5.3. IPM Continuity Check ......................................23
5.4. Reversing Valve Check....................................24
6. Temperature Sensor Resistance Values.. 25
6.1. Temperature Sensor Resistance Values..........25
6.2. Discharge Temperature Sensor Resistance
Values ..............................................................26
7. Pressure on Service Port .......................... 27
7.1. Cooling Chart (R-410A) ...................................27
7.2. Heating Chart (R-410A)...................................28
7.3. R-410 System Pressure...................................29
8. Wiring Diagrams ........................................ 30
8.1. MWCB Indoor Units.........................................30
8.2. MCB Outdoor Units..........................................31
8.3. MWHB Indoor Units.........................................32
8.4. MHB Outdoor Unit ...........................................33
9. Indoor and Outdoor Unit Disassembly .... 35
9.1. MWCB and MWHB Unit Disassembly .............35
9.1.1. Front Panel Removal ..........................35
9.1.2. Control Board Removal.......................37
9.1.3. Evaporator Coil Removal ....................37
9.1.4. Fan Removal.......................................38
9.1.5. Step Motor Removal ...........................38
MCB / MHB Single-Zone
Outdoor Units
MWCB / MWHB Wall Mount Single-Zone
Indoor Unit
MINI-SPLIT SYSTEMS SERVICE MANUAL
MCB/MWCB and MHB/MWHB
Series Diagnostic Information
100042 5/2022
Please refer to 100041 for indoor and outdoor unit information.

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9.1.6. Drain Hose Removal...........................39
9.2. Outdoor Unit Disassembly...............................39
9.2.1. MCB012S4S-1L, MCB009S4S-1P
and MCB012S4S-1P...........................39
9.2.2. MCB018S4S-1P, MCB024S4S-1P,
MHB009S4S-1L, MHB012S4S-1L
MHB009S4S-1P, MHB012S4S-1P
and MHB018S4S-1P...........................40
9.2.3. MHB024S4S-1P..................................41
9.3. Control Board Removal ...................................42
9.3.1. MCB024S4S-1P and
MHB024S4S-1P..................................42
9.3.2. MCB009S4S-1P, MCB012S4S-1P,
MCB018S4S-1P, MHB009S4S-1P,
MHB012S4S-1P, and
MHB018S4S-1P..................................43
9.3.3. MCB012S4S-1L, MHB009S4S-1L
and MHB012S4S-1L ...........................44
9.4. Outdoor Unit Fan and Fan Motor
Disassembly (All Models) ................................45
9.4.1. Fan Disassembly.................................45
9.4.2. Fan Motor Removal.............................45

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WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss
of life.
Installation and service must be performed by a licensed professional HVAC installer (or equivalent) or service agency
1. Safety Considerations
WARNING
Electric Shock Hazard. Can cause injury or death. Unit must be rounded in accordance with national and local codes.
Line voltage is present at all components when unit is not in operation. Disconnect all remote electric power supplies be-
fore opening access panel. Unit may have multiple power sources.
WARNING
Electricity remains in capacitors even when the power supply is off. Ensure the capacitors are fully discharged before
troubleshooting.
Test the voltage between P and
N on back of the main PCB with
multimeter. If the voltage is 36V, the
capacitors are fully discharged

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2. General Troubleshooting
2.1. Error Codes
When the indoor unit encounters detects an error condition the running LED with ash in a corresponding series, the timer
LED may turn on or begin ashing and display the error code. These error codes are described in the following tables:
Table 1. Indoor Display Alert and Status Codes and Outdoor Unit LED
Unit Error Codes
Outdoor Unit Main
Control Board
Indoor Unit
Display
Solution
MCB MWCB
System Error Codes
Indoor unit EEPROM error n/a EH 00 See “4.1. TS01-IDU” on
page 8.
Indoor unit EEPROM parameter error n/a EH 0A
Communication error between indoor unit and outdoor units n/a EL 01 See “4.3. TS02-S-INV” on
page 9.
Indoor fan speed error (DC motor) n/a EH 03 See “4.4. TS04-S-IDU” on
page 10.
Indoor room temperature sensor error (T1) n/a EH 60 See “4.6. TS05-IDU” on
page 14.
Indoor coil temperature sensor error (T2) n/a EH 61
Refrigerant leakage detection (Cooling mode only) n/a EL 0C See “4.8. TS06-INV” on
page 16.
Outdoor current overload protection n/a PC 08 See “4.10. TS08-S” on page
17.
Outdoor ambient temperature sensor error (T4) n/a EC 53
See “4.7. TS05-ODU” on
page 15.
Outdoor coil temperature sensor error (T3) n/a EC 52
Compressor discharge temperature sensor error (TP) n/a EC 54
Outdoor unit EEPROM error n/a EC 51 See “4.2. TS01-ODU” on
page 8.
Outdoor unit fan speed error (DC fan motor) n/a EC 07 See “4.5. TS04-S-ODU” on
page 13.
Inverter module IPM error n/a PC 00 See “4.11. TS09-S” on page
18.
High or Low voltage protection n/a PC 01 See “4.12. TS10-S” on page
19.
Compressor drive error n/a PC 04 See “4.13. TS12-S” on page
20.
Standby SLOW FLASH n/a
Normal operation LIT n/a
Outdoor unit error FAST FLASH n/a
Communication error between main control board and display board n/a EH 0b See “4.9. TS07” on page
16.
Operational Status Codes
46F heat mode (Heat pumps models only) n/a FP
Force Cooling n/a FC
Remote or Wired controller Lock n/a LL
Defrost (Heat pumps models only) n/a dF
Active clean n/a CL
Time On n/a On
Time Off n/a OF
Anti-cold Air Flow (Heat pumps models only) n/a cF
Remote On/Off n/a CP
ECO mode n/a On display 3
seconds
Outdoor Unit LED:
Slow ash: Flashing at 1Hz
Fast ash: Flashing at 2Hz

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2.2. Complaint Form
Request Number: Telephone Number:
Home Address:
Email:
Product Information
Indoor Unit Model: Outdoor Unit Model:
Outdoor Unit Serial #
Indoor Unit Serial #
Operation Mode: �Cooling �Heating �Fan Only �Dry
Temperature Setting: _ _ ºF Fan Speed: � Turbo � High � Medium � Low
� Auto
Temperature at Return _ _ ºF Temperature at Discharge: _ _ ºF
Installation / Condition Information
Indoor Temperature _ _ ºF Indoor Humidity _ _ % RH
Outdoor Temperature _ _ ºF Outdoor Humidity _ _ % RH
Piping Length Pipe Diameter Gas Pipe: Liq Pipe:
Wiring Length Wire Gauge
System Running Pressure MPa: _ _ Bar: _ _ PSI: _ _
Room Size (L*W*H)
Indoor Unit Installation Photo Outdoor Unit Installation Photo
Failure Descriptions
Issue Indoor Unit Error Code Outdoor Unit Error Code
Unit does not start.
Remote control does not work.
Indoor display is blank.
No cooling or heating.
Insufcient cooling or heating.
Unit Starts but stops immediately.
Excessive noise.
Excessive vibration
Wireless Remote Parameter Checking Information
Code being Displayed Description Display Value Description
T1 Room temperature
T2 Indoor coil temperature
T3 Outdoor coil temperature
T4 Ambient temperature
TP Discharge temperature
FT Target frequency
Fr Actual frequency
d1 Compressor current
Uo Outdoor AC voltage
Sn Indoor capacity test
Pr Outdoor fan speed
Lt EXV opening steps
ir Indoor fan speed
HU Indoor humidity
TT Adjusted temperature settings
oT GA algorithm frequency

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2.3. Engineering Mode for System Query
• To enter engineer mode, in power-on or standby mode
and in non-locked state, using the wireless remote
control, press the key combination ON/OFF button and
FAN button for 7 seconds.
• After entering the engineer mode, the wireless remote
control will display the following icons (Auto, Cool, Dry,
Heat and the Battery) at the same time. In addition, will
also display the numeric code of the current engineer
mode (engineer mode startup mode will display
numeric code 0).
• In engineer mode, the value of the current numeric
code can be adjusted using the Up/Down button. The
ranges of codes are O to 30.
• To exit engineer mode, using the wireless remote
control, press the key combination ON/OFF button and
FAN button for 2 seconds.
• Engineering mode will automatically end if there is no
valid key operation for 60 seconds.
ON/OFF BUTTON
FAN BUTTON
UP / DOWN BUTTON
2.3.1. Engineering Mode Codes
Table 2. Engineering Mode Codes
Display
Code
Query Content Description
0Default start code that will be displayed when going into
engineering mode.
1Room temperature T1 temperature
2Indoor coil temperature T2 temperature
3Outdoor coil temperature T3 temperature
4Ambient temperature T4 temperature
5Discharge temperature TP temperature
6Compressor Target Frequency FT Targeted Frequency
7Compressor Running Frequency Fr Actual Frequency
8Unit Current dl N/A
9Outdoor AC Voltage Uo N/A
10 Current indoor capacity test state Sn N/A
11 Reserve
12 Set Speed Pr of the outdoor fan Outdoor fan
speed=value*8
13 Opening Lr of EEV EXV opening angle-
value*8
14 Actual Running Speed ir of the
indoor fan
Indoor fan
speed=value*8
15 Indoor Humidity Hu N/A
16 Set Temperature TT after
compensation
N/A
17 - 19 Reserve
20 Indoor Target Frequency oT N/A
21 - 30 Reserve
2.3.2. Engineering Mode Error Codes
Table 3. Engineering Mode Error Codes
Coded Description Code
Indoor unit EEPROM error EH 00/EH 0A
Communication error between indoor unit and outdoor
units EL 01
Indoor fan speed error (DC motor) EH 03
Indoor room temperature sensor error (T1) EH 60
Indoor coil temperature sensor error (T2) EH 61
Refrigerant leakage detection (Cooling mode only) EL 0C
Communication error between main control board and
display board EH 0b
Outdoor current overload protection PC 08
Outdoor ambient temperature sensor error (T4) EC 53
Outdoor coil temperature sensor error (T3) EC 52
Compressor discharge temperature sensor error (TP) or
sometimes referred to as (T5) EC 54
Outdoor unit EEPROM error EC 51
Outdoor unit fan speed error (DC fan motor) EC 07
Inverter module IPM error PC 00
High or Low voltage protection PC 01
Outdoor low ambient temperature protection PC 0L
Compressor drive error PC 04
Outdoor ambient temperature too low PC 0L

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3. Quick Maintenance by Error Code
The following is a part replacement matrix based on the active error code.
Table 4. Component Replacement Based on Error Code (Part 1)
Part Requiring Replacement Error Code
EH 00 / EH 0A EL 01 EH 03 EH 60 EH 61 EH 0b EL 0C PC 08
Indoor PCB √√√√√√√X
Outdoor PCB X√XXXXX√
Display board XXXXX√X X
Indoor fan motor X X √XXXXX
T1 sensor XXX√XXXX
T2 sensor XXXX√X√X
T2B sensor XXXXXXXX
Reactor X√XXXXXX
Compressor XXXXXXX√
Additional refrigerant XXXXXX√X
Table 5. Component Replacement Based on Error Code (Part 2)
Part Requiring Replacement
Error Code
EC 53 EC 52 EC 54 EC 51 EC 07 PC 00 PC 01 PC 04
Indoor PCB √√√√√√√√
Outdoor PCB XXXXXXXX
Outdoor fan motor XXXX√ √ X√
T3 sensor X√XXXXXX
T4 sensor √XXXXXXX
TP sensor X X √XXXXX
Reactor XXXXXX√X
Compressor XXXXX√X√
IPM module board XXXXX√ √ √
High pressure protector XXXXXXXX
Low pressure protector XXXXXXXX
Additional refrigerant XXXXXXXX
NOTE: For certain models, the outdoor PCB can not be removed separately. In this case, the outdoor electric control
box should be replaced as a whole.

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4. Troubleshooting by Error Code
4.1. TS01-IDU
Description: Indoor PCB main chip is not receiving feedback from the EEPROM chip.
Possible Affected Components: Outdoor PCB
Troubleshooting and Repair:
Shu o the power supply for
two minutes.
Remarks: A read-only memory that can be erased and reprogrammed using a pulsed voltage.
NOTE: On various models the indoor PCB can not be removed separately. In this situation the entire indoor electric
control box should be replaced.
4.2. TS01-ODU
Description: Outdoor PCB main chip is not receiving feedback from the EEPROM chip or compressor driven chip.
Possible Affected Components: Outdoor PCB
Troubleshooting and Repair:
Replace the outdoor main PCB
Shut o the power supply
for two minutes.
Remarks: A read-only memory that can be erased and reprogrammed using a pulsed voltage.
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced.

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4.3. TS02-S-INV
Description: Indoor unit cannot communicate with the outdoor unit.
Possible Affected Components: Indoor PCB, Outdoor PCB, IPM PCB or short-circuited component.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced.
Remarks:
• Use a multimeter to test the DC
voltage between two terminals
(2 and 3).
• When the system is normally
running, the voltage should
alternate between -25V to 25V).
• If the outdoor unit has
malfunction, the voltage will
move alternately with positive
values.
• If the indoor unit has
malfunction, the voltage will
between a certain value.

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Description: Indoor unit cannot communicate with the outdoor unit.
• Use a multimeter to test the
resistance of the reactor which
does not connect with the
capacitor.
• The normal value should be
zero ohm. Any other reading
typically indicates the reactor
has malfunction.
4.4. TS04-S-IDU
Description: When the indoor fan speed is to low or to high undeterminate amount of time, the LED displays the failure
code and the system turns off.
Possible Affected Components: Indoor main PCB, fan motor, fan assembly or connection wires.
Troubleshooting and Repair:

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Description: When the indoor fan speed is to low or to high undeterminate amount of time, the LED displays the failure
code and the system turns off.
1. Indoor DC Fan motor (control chip is
integrated with fan motor.
Power up the system and when the unit is in standby mode, measure the
voltage of pin 1 - pin 3 and pin 4 - pin 3 on the fan motor connection. If the
value of the voltage is not in the range showing in the table below, the PCB
must have issues and needs to be replaced.
• DC motor voltage input and output (voltage: 220-240VAC~):
• DC motor voltage input and output (voltage: 115V~):

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Description: When the indoor fan speed is to low or to high undeterminate amount of time, the LED displays the failure
code and the system turns off.
2. Indoor unit Fan motor:
a. Power off and disconnect fan motor power cord from the PCB. Measure the
resistance value of each winding by using a multimeter. The normal values
are show as shown to the right.
b. Power on the system and set the unit running in fan mode at the highest fan
speed. After running for 15 seconds measure the voltage of pin 1 and pin
2. If the value of the voltage is less than 100V (208~240V power supply) or
50V (115V power supply)the indoor control PCB has an issues and will need
to be replaced.
Input Terminals

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4.5. TS04-S-ODU
Description: When the outdoor fan speed is to low or to high undeterminate amount of time, the LED displays the
failure code and the system turns off.
Possible Affected Components: Outdoor main PCB, fan motor, fan assembly or connection wires.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced.
1. Outdoor DC Fan motor (control chip
is integrated with fan motor.
• Release the UVW connector. Measure the resistance of U-V, U-W and
V-W. If the resistance is not equal to each other, the fan motor must
have an issue and will need to be replaced or the PCB has the issue
and it must be replaced.

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Description: When the outdoor fan speed is to low or to high undeterminate amount of time, the LED displays the
failure code and the system turns off.
2. Outdoor DC Fan Motor (control chip
is integrated on the PCB:
Power on the system and place the unit in standby mode. Measure the
voltage between pin 1 and pin 3, pin 4 and pin 4 on the fan motor connector.
If the value of the voltage is not in the range showing in the below table, the
outdoor PCB must issues and will need to be replaced.
4.6. TS05-IDU
Description: Open circuit or short circuit of indoor temperature sensors (T1 or T2). If the sampling voltage is lower than
0.06V or higher than 4.94V, the LED displays the failure code.
Possible Affected Components: Indoor main PCB, sensors or connection wires.
Troubleshooting and Repair:
This illustration and the value displayed is only an exampled and actual appearance and value may vary.

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4.7. TS05-ODU
Description: Open circuit or short circuit of indoor temperature sensors (T3, T4 and TP). If the sampling voltage is lower
than 0.06V or higher than 4.94V, the LED displays the failure code.
Possible Affected Components: Indoor main PCB, sensors or connection wires.
Troubleshooting and Repair:Replace the outdoor
main PCB
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced. This illustration and the value displayed is only an exampled and actual appear-
ance and value may vary.

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4.8. TS06-INV
Description: Refrigerant Leakage Detection. Evaluate abnormal operation of the refrigeration system according to the
number of compressor stops and the changes in the operating parameters caused by excessive exhaust temperature.
Possible Affected Components: Indoor main PCB or need to add refrigerant.
Troubleshooting and Repair:
4.9. TS07
Description: Indoor PCB / display board communication error. Indoor PCB does not receive feedback from the display
board.
Possible Affected Components: Indoor main PCB,display board or communication wiring.
Troubleshooting and Repair:
Turn power o to the system, then
wait two minutes before restarting.

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4.10. TS08-S
Description: Current overload protection. An abnormal current rise is detected by checking the specied current
detection circuit.
Possible Affected Components: Reactor, outdoor fan, outdoor PCB or communication wiring.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced

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4.11. TS09-S
Description: IPM malfunction or IGBT high current protection. When the IPM voltage signal to the compressor drive
chip is abnormal, the LED displays the failure code and the system will turn off.
Possible Affected Components: Outdoor PCB, compressor, outdoor fan assembly, IPM module board or connection
wires.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced

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4.12. TS10-S
Description: High or low voltage protection. Abnormal increases or decreases in voltage are detected by checking the
specied voltage detection circuit.
Possible Affected Components: Power supply wiring, IPM module board, Outdoor PCB or reactor.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced

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4.13. TS12-S
Description: Inverter compressor drive error. An abnormal inverter compressor drive is detected by a special detection
circuit that includes communication signal detection, voltage detection and compressor rotation speed signal detection.
Possible Affected Components: Connection wires, IPM module board, outdoor fan assembly, compressor or outdoor
PCB.
Troubleshooting and Repair:
NOTE: On various models the outdoor PCB can not be removed separately. In this situation the entire outdoor electric
control box should be replaced