MrCool DIY E Star Series User manual

Due to updates and constantly improving performance, the information and instructions
within this manual are subject to change without notice. Please visit
www.mrcool.com/documentation to ensure you have the latest version of this manual.
Version Date: 10-22-21
Troubleshooting &
Solutions Guide
DIY® E Star™
4th Generation
Series

Contents
1. Safety Caution .......................................................................................................3
2. General Troubleshooting......................................................................................4
3. Complain Record Form..........................................................................................6
4. Information Inquiry ...............................................................................................8
5. Error Diagnosis and Troubleshooting Without Error Code...............................11
5.1 Remote maintenance...................................................................................11
5.2 Field maintenance.......................................................................................12
6. Quick Maintenance by Error Code......................................................................17
7. Troubleshooting by Error Code...........................................................................18
7.1 EH 00 / EC 51 (EEPROM parameter error diagnosis and solution)...........18
7.2 EL 01 (Indoor and outdoor unit communication error diag. and solution).. 19
7.3 EH 02 (Zero-crossing detection error diagnosis and solution). ................... 21
7.4 EH 03 / EC 07 (Fan speed is operating outside of the normal range
diagnosis and solution) .............................................................................. 22
7.5 EH 60/EH 61/EC 53/EC 52/EC 54/EC 56 (Open circuit or short circuit of
temperature sensor diagnosis and solution)............................................... 25
7.6 EH 0b (Indoor PCB / Display board communication error diagnosis and
solution) ..................................................................................................... 26
7.7 EL 0C (Refrigerant Leakage Detection diagnosis and solution) ................ 27
Troubleshooting

Contents
7.8 PC 08 (Overload current protection diagnosis and solution) .................... 28
7.9 PC 00 (IPM malfunction or IGBT over-strong current protection diagnosis
and solution) ............................................................................................. 29
7.10 PC 01 (Over voltage or too low voltage protection diag. and solution)...... 30
7.11 PC 02 (High temperature protection of IPM module or high pressure
protection diagnosis and solution) ............................................................ 31
7.12 PC 04 (Inverter compressor drive error diagnosis and solution)............... 33
7.13 PC 03 (Low pressure protection diagnosis and solution).......................... 34
8. Check Procedures.. ............................................................................................. 36
Troubleshooting

Troubleshooting 3
1. Safety Caution
WARNING
Be sure toturn off all power supplies or disconnect all wires to avoidelectric shock.
While checking indoor/outdoor PCB, pleaseequip oneself with anti-static gloves or wrist
strap to avoid damage to the board.
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 lower than 36V, the
capacitors are fully discharged.
Note: This picture is for reference only. Actual appearance may vary.

Troubleshooting 4
2. General Troubleshooting
2.1 Error Display (Indoor Unit)
When the indoor unit encounters a recognized error, the operation lamp will flash in a corresponding series, the timer
lamp may turn on or begin flashing, and an error code will be displayed. These error codes are described in the following
table:
Operation
Lamp
Timer
Lamp
LED
Display Error Information Solution
1 time OFF EH 00 Indoor unit EEPROM parameter error TS18
2 times OFF EL 01 Indoor /outdoor unit communicationerror TS19
3 times OFF EH 02 Zero-crossing signal detection error (for some models) TS21
4 times OFF EH 03 The indoor fan speed is operating outside of the normal range TS22
5 times OFF EC 51 Outdoor unit EEPROM parameter error (for some models) TS18
5 times OFF EC 52 Condenser coil temperature sensor T3 is in open circuit or has short
circuited TS25
5 times OFF EC 53 Outdoor room temperature sensor T4 is in open circuit or has short
circuited TS25
5 times OFF EC 54 Compressor discharge temperature sensor TP is in open circuit or
has short circuited TS25
5 times OFF EC 56 Evaporator coil outlet temperature sensor T2B is in open circuit or
has short circuited (for free-match indoor units) TS25
6 times OFF EH 60 Indoor room temperature sensor T1 is in open circuit or has short
circuited TS25
6 times OFF EH 61 Evaporator coil temperature sensor T2 is in open circuit or has short
circuited TS25
12 times OFF EC 07 The outdoor fan speed is operating outside of the normal range
for some models)TS22
9 times OFF EH 0b Indoor PCB / Display board communication error TS26
8 times OFF EL 0C Refrigerant leak detected TS27
7 times FLASH PC 00 IPM malfunction or IGBT over-strong current protection TS29
2 times FLASH PC 01 Over voltage or over low voltage protection TS30
3 times FLASH PC 02 High temperature protection of IPM module or High pressure
protection (for some models) TS31
5 times FLASH PC 04 Inverter compressor drive error TS33
1 time FLASH PC 08 Current overload protection (for some models) TS28
7 times FLASH PC 03 Low pressure protection (for some models) TS34
1 times ON -- Indoor units mode conflict (match with multi outdoor unit) --

Troubleshooting 5
For other errors:
The display board may show a garbled code or a code undefined by the service manual. Ensure that this code is not a
temperature reading.
Troubleshooting:
Test the unit using the remote control. If the unit does not respond to the remote, the indoor PCB requires replacement.
If the unit responds, the display board requires replacement.
LED flash frequency:
... ...
2.2 Error Display (For Some Outdoor Units)
There are 2 LED lights (RED color and GREEN color) welded in outdoor main board. After power on, LED show different
actions when encounter different problems.
No. Problem LED(GREEN) LED(RED) Solution
1 Standby normally ON OFF -
2 Operate normally OFF ON -
3 Compressor driven chip EEPROM parameter error ON FLASH TS19
4 IPM malfunction or IGBT over-strong current protection Flash OFF TS30
5 Over voltage or too low voltage protection ON ON TS31
6 Inverter compressor drive error OFF FLASH TS34
7 Inverter compressor drive error Flash LIGHT TS34
8Communication error between outdoor main chip and
compressor driven chip flash FLASH TS19

Troubleshooting 6
3. Complain Record Form
Complain Record Form
Request No.: Date:
Installation Date: Service Date:
Customer Information
Name Telephone No.
Home Address
Email
Product Information
Indoor Unit Model Outdoor Unit Model
Serial No. of indoor unit
Serial No. of outdoor unit
Working Mode □Cooling □Heating □Fan only □Dry
Setting temperature °C / °F Fan speed □Turbo □High □Medium □Low
□Auto
Temperature of air inlet °C / °F Temperature of air
outlet °C / °F
Installation / Condition Information
Indoor temperature °C / °F Indoor humidity %RH
Outdoor temperature °C / °F Outdoor humidity %RH
Length of Connecting pipe Pipe diameter Gas pipe: Liquid pipe:
Length of Wiring wire diameter
System Running Pressure MPa or Bar or PSI
Room size (L*W*H)
Photo of Installation of In-
door unit
(Photo #1)
Photo of Installation
of Outdoor unit
(Photo #2)
Failure Description
Error Code of Indoor unit Code of Outdoor
PCB
Unit does not start
Remote control does not work
Indoor display shows nothing
No cooling or heating at all
Less cooling or heating
Unit starts but stops shortly
High noise
High vibration

Troubleshooting 7
Parameter Checking information by Remote controller
Displaying code Displaying code meaning Display value Display value meaning
T1 Room temperature
T2 Indoor coil temperature
T3 Outdoor coil temperature
T4 Ambient temperature
Tb Outlet temperature of
indoor coil
TP Discharge temperature
TH Sunction temperature
FT Targeted Frequency
Fr Actual Frequency
IF Indoor fan speed
OF Outdoor fan speed
LA EXV opening steps
CT Compressor continuous
running time
ST Causes of compressor
stop.
A0, A1, b0, b1, b2, b3, b4,
b5, b6, dL, Ac, Uo, Td, dA,
dS, dT
Reserved
Approval from Manufacturer
□Approved
□More Proof needed
□Rejected

Troubleshooting 8
4. Information Inquiry
• To enter information inquiry status, complete the following procedure within ten seconds:
• Press LED (or DO NOT DISTURB)
3 times.
• Press SWING (or AIR DIRECTION) 3 times.
• Finish 1 and 2 within 10 seconds, you will hear beeps for two seconds, which means the unit goes into parameter
checking mode.
• Use the LED (or DO NOT DISTURB) and SWING (or AIR DIRECTION) buttons to cycle through information displayed.
• Pressing LED (or DO NOT DISTURB) will display the next code in the sequence. Pressing SWING (or AIR
DIRECTION) will show the previous.
• The following table shows information codes. The screen will display this code for two seconds, then the information
for 25 seconds.

Troubleshooting 9
Displayed code Explanation Displayed
value Meaning Additional Notes
T1
T2
T3
T4
Tb
TP
TH
FT
Fr
Room temperature
-1F,-1E,-1d,-1c,-
1b,-1A
-19—99
A0,A1,…A9
b0,b1,…b9
c0,c1,…c9
d0,d1,…d9
E0,E1,…E9
F0,F1,…F9
-25,-24,-23,-22,
-21,-20
-19—99
100,101,…109
110,111,…119
120,121,…129
130,131,…139
140,141,…149
150,151,…159
1. All displayed temperatures
use actual values.
2. All temperatures are
displayed in °C regardless
of remote used.
3. T1, T2, T3, T4, and T2B
display ranges from -25 to
70 °C. TP display ranges
from -20 to 130 °C.
4. The frequency display
ranges from 0 to 159HZ.
5. If the actual values exceed
or fall short of the defined
range, the values closest
to the maximum and
minimum values will be
displayed.
Indoor coil
temperature
Outdoor coil
temperature
Ambient
temperature
Outlet temperature
of indoor coil
Discharge
temperature
Suction temperature
Targeted frequency
Actual frequency
IF Indoor fan speed
0
1,2,3,4
14-FF
OFF
Low speed, Medium
speed, High speed,
Turbo.
Actual fan speed is
equal to the display
value converted to
decimal value and
multiplied by 10. This
is measured in RPM.
N/A
Used for some large capacity
motors.
Used for some small capacity
motors.
The display value is 14-FF
(hexadecimal). The
corresponding fan speed
ranges from 200 to 2550 RPM.
OF Outdoor fan speed
LA EXV opening angle 0-FF
Actual EXV opening
value is equal to
the display value
converted to decimal
value and then
multiplied by2.
-
CT
Compressor
continuous running
time
0-FF 0-255 minutes
If the actual value exceeds
or falls short of the defined
range, the value closest to the
maximum and minimum will
be displayed.
ST Causes of
compressor stop 0-99
For a detailed
explanation, contact
technical support.
-

Troubleshooting 10
Displayed code Explanation Displayed
value Meaning Additional Notes
A0
Reserved
0-FF
2-28
5-20
5-25
- -
A1
0
1
2
3
4
5
6
L
A
U
T
A
5
T

Troubleshooting 11
5. Error Diagnosis and Troubleshooting Without Error Code
WARNING
Be sure to turn off unit before any maintenance to prevent damage or injury.
5.1 Remote maintenance
SUGGESTION: When troubles occur, please check the following points with customers before field maintenance.
No. Problem Solution
1 Unit will not start TS13 - TS14
2 The power switch is on but fans will not start TS13 - TS14
3 The temperature on the display board cannot be set TS13 - TS14
4 Unit is on but the wind is not cold (hot) TS13 - TS14
5 Unit runs, but shortly stops TS13 - TS14
6 The unit starts up and stops frequently TS13 - TS14
7 Unit runs continuously but insufficient cooling (heating) TS13 - TS14
8 Cool can not change to heat TS13 - TS14
9 Unit is noisy TS13 - TS14

Troubleshooting 12
5.2 Field maintenance
Problem Solution
1 Unit will not start TS15 - TS16
2 Compressor will not start but fans run TS15 - TS16
3 Compressor and condenser (outdoor) fan will not start TS15 - TS16
4 Evaporator (indoor) fan will notstart TS15 - TS16
5 Condenser (Outdoor) fan will not start TS15 - TS16
6 Unit runs, but shortly stops TS15 - TS16
7 Compressor short-cycles due to overload TS15 - TS16
8 High discharge pressure TS15 - TS16
9 Low discharge pressure TS15 - TS16
10 High suction pressure TS15 - TS16
11 Low suction pressure TS15 - TS16
12 Unit runs continuously but insufficient cooling TS15 - TS16
13 Too cool TS15 - TS16
14 Compressor is noisy TS15 - TS16
15 Horizontal louver cannot revolve TS15 - TS16

Troubleshooting 13
1. Remote Maintenance
Possible causes of trouble
Power failure
The main power tripped Loose connecons
Faulty transformer
The voltage is too high or too low
The remote control is powered o
Broken remote control Dirty air ter
Dirty condenser ns The seng temperature is higher/lower than the room's(cooling/heang)
The ambient temperature is too high/low when the mode is cooling/heang
Fan mode
SILENCE funcon is acvated (oponal funcon)
Frosng and defrosng frequently
Unit will not start
The power switch is on but fans will not start
The temperature on the display board cannot be set
Unit is on but the wind is not cold (hot)
Unit runs, but shortly stops
The unit starts up and stops frequently
Unit runs connuously but insucient cooling (heang)
Cool can not change to heat
Unit is noisy
Test method / remedy
Test voltage
Close the power switch
Inspect connecons - ghten
Change the transformer Test voltage
Replace the baery of the remote control
Replace the remote control
Clean or replace
Clean
Adjust the seng temperature Turn the AC later Adjust to cool mode
Turn oSILENCE funcon.
Turn the AC later
Refrigerant Circuit
Electrical Circuit

Troubleshooting 14
1. Remote Maintenance
Possible causes of trouble
Heavy load condion
Loosen hold down bolts and / or screws
Bad airproof
The air inlet or outlet of either unit is blocked
Interference from cell phone towers and remote boosters
Shipping plates remain aached
Unit will not start
The power switch is on but fans will not start
The temperature on the display board cannot be set
Unit is on but the wind is not cold (hot)
Unit runs, but shortly stops
The unit starts up and stops frequently
Unit runs connuously but insucient cooling (heang)
Cool can not change to heat
Unit is noisy
Test method / remedy
Check heat load
Tighten bolts or screws
Close all the windows and doors
Remove the obstacles Reconnect the power or press ON/OFF buon on remote control to restart operaon
Remove them
Others

Troubleshooting 15
2. Field Maintenance
Possible causes of trouble
Power failure
Blown fuse or varistor
Loose connecons
Shorted or broken wires Safety device opens
Faulty thermostat / room temperature sensor Wrong seng place of temperature sensor
Faulty transformer
Shorted or open capacitor
Faulty magnec contactor for compressor Faulty magnec contactor for fan
Low voltage
Faulty stepping motor
Shorted or grounded compressor Shorted or grounded fan motor
Unit will not start
Compressor will not start but fans run
Compressor and condenser (outdoor) fan will not start
Evaporator (indoor) fan will not start
Condenser (Outdoor) fan will not start
Unit runs, but shortly stops
Compressor short-cycles due to overload
High discharge pressure
Low discharge pressure
High sucon pressure
Low sucon pressure
Unit runs connuously but insucient cooling
Too cool
Compressor is noisy
Horizontal louver can not revolve
Test method / remedy
Test voltage Inspect fuse type & size
Inspect connecons - ghten
Test circuits with tester
Test connuity of safety device
Test connuity of thermostat / sensor & wiring
Place the temperature sensor at the central of the air inlet grille Check control circuit with tester Check capacitor with tester Test connuity of coil & contacts
Test connuity of coil & contacts
Test voltage Replace the stepping motor
Check resistance with mulmeter Check resistance with mulmeter
Electrical Circuit

Troubleshooting 16
2.Field Maintenance
Possible causes of trouble
Compressor stuck
Shortage of refrigerant
Restricted liquid line Dirty air ter
Dirty evaporator coil
Insucient air through evaporator coil Overcharge of refrigerant
Dirty or parally blocked condenser
Air or incompressible gas in refrigerant cycle
Short cycling of condensing air
High temperature condensing medium Insucient condensing medium Broken compressor internal parts
Inecient compressor
Expansion valve obstructed
Expansion valve or capillary tube closed completely
Leaking power element on expansion valve Poor installaon of feeler bulb Heavy load condion
Loosen hold down bolts and / or screws
Shipping plates remain aached
Poor choices of capacity
Contact of piping with other piping or external plate
Unit will not start
Compressor will not start but fans run
Compressor and condenser (outdoor) fan will not
start
Evaporator (indoor) fan will not start
Condenser (Outdoor) fan will not start
Unit runs, but shortly stops
Compressor short-cycles due to overload
High discharge pressure
Low discharge pressure
High sucon pressure
Low sucon pressure
Unit runs connuously but insucient cooling
Too cool
Compressor is noisy
Horizontal louver can not revolve
Test method / remedy
Replace the compressor
Leak test
Replace restricted part
Clean or replace Clean coil
Check fan Change charged refrigerant volume
Clean condenser or remove obstacle
Purge, evacuate and recharge
Remove obstrucon to air ow
Remove obstrucon in air or water ow
Remove obstrucon in air or water ow
Replace compressor
Test compressor eciency
Replace valve
Replace valve
Replace valve
Fix feeler bulb Check heat load Tighten bolts or screws Remove them
Choose AC of lager capacity or add the number of AC
Recfy piping so as not to contact each other or with external
plate
Refrigerant Circuit
Others

Troubleshooting 17
6. Quick Maintenance by Error Code
If you do not have the time to test which specific parts are faulty, you can directly change the required parts according
the error code.
You can find the parts to replace by error code in the following table.
Part requiring replacement
Error Code
EH 00 EL 01 EH 02 EH 03 EH 60 EH 61 EH 0b EL 0C PC 08
Indoor PCB x
Outdoor PCB x xxxxxx
Display board xxxxxx xx
Indoor fan motor xxx xxxxx
T1 sensor xxxx xxxx
T2 Sensor xxxxx x x
Reactor x xxxxxxx
Compressor xxxxxxxx
Additional refrigerant xxxxxxx x
Part requiring
replacement EC 53 EC 52 EC 54 EC 56 EC 51 EC 07 PC 00 PC 01 PC 02 PC 03 PC 04
Indoor PCB xxxxxxxxxxx
Outdoor PCB
Indoor fan motor xxxxxxxxxxx
Outdoor fan motor xxxxx x x
T3 Sensor x xxxxxxxxx
T4 Sensor xxxxxxxxxx
TP Sensor xx xxxxxxxx
T2B Sensor xxx xxxxxxx
Reactor xxxxxxx xxx
Compressor xxxxxx xxx
IPM module board xxxxxx x
High pressure protector xxxxxxxx xx
Low pressure protector xxxxxxxxx x
Additional refrigerant xxxxxxxxx x
Note: For certain models, outdoor PCB could not be removed separately. In this case, the outdoor electric
control box should be replaced as a whole.

Troubleshooting 18
7. Troubleshooting by Error Code
7.1 EH 00 / EC 51 (EEPROM parameter error diagnosis and solution)
Description: Indoor or outdoor PCB main chip does not receive feedback from EEPROM chip.
Recommended parts to prepare:
• Indoor PCB
• Outdoor PCB
Troubleshooting and repair:
Shut off the power supply and
turn it on 2 minutes later.
Is it still displaying
the error code?
YES
Replace theindoor main
PCB(EH00) /outdoor main
PCB(EC51).
The unit is operating normally.NO
Remarks:
EEPROM:A read-only memory whose contents can be erased and reprogrammed using a pulsed voltage.
The location of the EEPROM chip on the indoor and outdoor PCB is shown in the following two images:
Note: For certain models, outdoor PCB could not be removed separately. In this case, the outdoor electric
control box should be replaced as a whole. This pictures are only for reference, actual appearance may vary.
Troubleshooting and repair of compressor driven chip EEPROM parameter error and communication error
between outdoor main chip and compressor driven chip are same as EC 51.

Troubleshooting 19
7.2 EL 01 (Indoor and outdoor unit communication error diagnosis and solution)
Description: Indoor unit can not communicate with outdoor unit
Recommended parts to prepare:
• Indoor PCB
• Outdoor PCB
• Short-circuited component
Troubleshooting and repair:
Does the error code
disappear ?
Power off, then restart the unit after 2
minutes.
Measure the DC voltage between N/L2
and S(Black pin to N/LN, Red pin to S).
The value is fixed and close
to 0
The value is alternative
from negative to positive
The value is always positive
Check the wiring connection
between indoor and outdoor
unit, are they good?
Check the wiring connection
from outdoor terminal to
outdoor PCB and wiring
between PCBs if there is
more than 1 PCB
Check the wiring connection
from indoor terminal to indoor
PCB, are they good?
Turn on the unit, check if W
and 1(L) is connected?
Check if the power LED is
on?
Yes
Yes
Yes
Unplug all the high voltage
components connected to main
PCB such as 4 way valve, heater,
AC fan one by one to check their
resistance. Is there any component
short circuit?
Unplug electronic expansion valve.
Check if power LED is on ?
No
No
Check the AC voltage of L,N
output to IPM board, is it same
as power input?
Check the DC5V, 12V
from IPM board to main
PCB, are they normal?
Unplug all the high voltage
components connected to main
PCB such as 4 way valve, heater,
AC fan one by one to check their
resistance. Is there any component
short circuit?
Yes
No
Unplug electronic expansion valve.
Check if the DC5V, 12V to main
PCB are OK
Replace short-circuited
component and main
PCB
Replace coil of electronic
expansion valve
Replace outdoor PCB
Replace short- circuited
component and outdoor
PCB
Yes
Yes
Yes
Replace main PCBNo
No
Replace IPM board
No
Replace indoor PCB
No
Solved
Correct the connection or
change wires
No
No
Yes
For units with main PCB and IPM board
both
For units with only one
PCB
For units
with W wire
For units without W
wire
No
Yes
Yes
Note: For certain models, outdoor PCB could not be removed separately. In this case, the outdoor electric
control box should be replaced as a whole.