Toyotomi KURO User manual

Mini Service Manual
v.2-2020

41

41
KURO
IZURU
HIRO
FLOOR STANDING

37
Display method of indoor unit
Malfunction
name AC status Possible causes
Error
code
Indicator display
Power
indicator
Cool
indicator
Heat
indicator
Flash
15
times
Malfunction of
jumper cap
The complete unit stops operation 1. Jumper cap is not installed in control panel;
2. Poor contact of jumper cap;
3. Jumper cap is damaged;
4. The tested circuit of jumper cap on control panel is abnormal.
Flash 6
times
Communication
malfunction
between indoor
unit and outdoor
unit
Cool: compressor stops
operation, while indoor fan
operates;
Heat: all loads stops operation.
See Page 46 “Communication malfunction”
Flash 5
times
IPM protection Cool/Dry: compressor stops
operation, while indoor fan
operates.
Heat: all loads stops operation.
See Page 48 “IPM protection, over-phase current of
compressor”
Malfunction of
outdoor fan/
malfunction of
DC motor
Cool/Dry: all loads stops
operation except indoor fan.
Heat: all loads stops operation.
1. Outdoor condenser, air inlet and air outlet are blocked by lth
or dirt;
2.Fan is blocked or loosened;
3.Motor or connection wire of motor is damaged;
4.Main board of outdoor unit is damaged;
(As for dual-outdoor fan, L3 indicates fan 1; LA indicates fan 2)
Flash 3
times
Overload
protection of
compressor
Cool/Dry: compressor stops
operation, while indoor fan
operates.
Heat: all loads stops operation.
1. Overload wire of compressor is loose;
2. The overload protector is damaged. Under normal
circumstances, the resistance between both ends of terminal is
less than 1ohm.
3.See Page 49 “Overload protection of compressor , High
discharge temperature protection of compressor”
Refrigerant
insufcient
protection, cut-
off protection of
refrigerant
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates;
Heat: Compressor, outdoor fan
and indoor fan stops operation.
1. Is system cooling under high humidity environment, thus
temperature difference of heat transfer is small;
2. Check whether the big valve and small valve of outdoor unit
are opened completely;
3. Is the temperature sensor of evaporator of indoor unit loose?
4. Is the temperature sensor of condenser of outdoor unit
loose?
5. Is the capillary or the electronic expansion valve blocked?
6. Is refrigerant leaking?
Flash
once
Indoor ambient
temperature
sensor is open/
short-circuited
Cool/Dry: indoor fan operates,
while compressor and outdoor fan
stops operation;
Heat: all loads stops operation.
1. Temperature sensor is not well connected;
2. Temperature sensor is damaged
(refer to Page 69 “Table 1”)
3. Main board of indoor unit is damaged.
Flash
twice
Indoor
evaporator
temperature
sensor is open/
short-circuited
Cool/Dry: indoor fan operates,
while compressor and outdoor fan
stops operation;
Heat: all loads stops operation.
1. Temperature sensor is not well connected;
2. Temperature sensor is damaged
(refer to Page 69 “Table 2”)
3. Main board of indoor unit is damaged.
Flash
11
times
No feedback
from indoor
unit’s motor
The complete unit stops operation 1. Is the fan blocked?
2. Is the motor terminal loose?
3. Is the connection wire of motor damaged?
4. Is the motor damaged?
5. Is the main board of indoor unit damaged?
Indoor unit and
outdoor can be
matched with
each other
Heat: compressor, outdoor unit
and indoor fan stops operation.
Capacity of indoor unit and outdoor unit can’t be matched.
Malfunction of
jumper cap of
outdoor unit
Heat: all loads are stopped;
other modes: outdoor unit stops
operation.
Jumper cap of outdoor unit hasn’t been installed.
Flash
22
times
Gas valve
temperature
sensor is ON /
short-circuited
1. Temperature sensor is not well connected or damaged; (refer
to Page 69 “Table 2”)
2. The wire of temperature sensor is damaged, causing short
circuit to copper pipe or outer casing;
3. Main board of outdoor unit is damaged.
Error Code List
Applicable model: SPLIT TYPE and FLOOR STANDING

38
Display method of indoor unit
Malfunction
name AC status Possible causes
Error
code
Indicator display
Power
indicator
Cool
indicator
Heat
indicator
Flash
19
times
Liquid valve
temperature
sensor is ON /
short-circuited
1. Temperature sensor is not well connected or damaged; (refer
to Page 69 “Table 2”)
2. The wire of temperature sensor is damaged, causing short
circuit to copper pipe or outer casing;
3. Main board of outdoor unit is damaged.
Flash
once
High pressure
protection of
system
Cool/Dry: all loads stops
operation except indoor fan;
Heat: all loads stops operation.
1. Heat exchange of outdoor unit is too dirty, or it blocked the
air inlet/outlet;
2. Ambient temperature is too high;
3. Is power voltage normal; (three-phase unit)
4. Refrigerant is too much.
5. Wiring of high pressure switch is loose or high pressure
switch is damaged;
6. The internal system is blocked; (dirt blockage, ice blockage,
oil blockage, angle valve is not completely opened)
7. Main board of outdoor unit is damaged;
Flash 3
times
Low pressure/
low system
pressure
protection/
compressor
low pressure
protection
Cool: compressor, outdoor fan
and indoor fan stop operation;
Heat: compressor and outdoor
fan stop operation at rst. About
1min later, indoor fan stops
operation; 2mins later, the 4-way
valve stop operation.
1. Low pressure switch is damaged;
2. Refrigerant inside the system is insufcient.
Flash 4
times
High discharge
temperature
protection of
compressor
Cool/Dry: compressor and
outdoor fan stops operation, while
indoor fan operates;
Heat: all loads stops operation.
See Page 49 “Overload protection of compressor , High
discharge temperature protection of compressor”
Fixed speed unit:
1. System abnormality; (e.g.: blockage)
2. Rotate speed of outdoor motor is abnormal; (cooling)
3. Outdoor air inlet is abnormal; (cooling)
4. System is normal, but the resistance of compressor
exhausting temperature sensor is abnormal or poorly
connected.
Flash 5
times
AC overcurrent
protection
Cool/Dry: compressor and
outdoor fan stops operation, while
indoor fan operates;
Heat: all loads stops operation.
1. Power voltage is unstable;
2. Power voltage is too low;
3. System load is too high, which leads to high current;
4. Heat exchange of indoor unit is too dirty, or it blocked the air
inlet/outlet;
5. Fan motor operation is abnormal; the fan speed is too low or
not functioning;
6. Compressor is blocked;
7. The internal system is blocked; (dirt blockage, ice blockage,
oil blockage, angle valve is not completely opened)
8. Main board of outdoor unit is damaged.
See Page 60 “AC overcurrent protection”
Flash 7
times
Mode shock/
sysmte mode
shock
Load of indoor unit stops
operation (indoor fan, E-heater,
swing)
Malfunction of one-to-more system; there may be two indoor
units which has set the shock mode, such as one is cooling
and the other is heating.
Flash 8
times
High
temperature
prevention
protection
Cool: compressor stops operation
while indoor fan operates;
Heat: all loads stops operation.
See Page 53 “High temperature prevention protection; high
power; system isabnormal”
Flash
15
times
Malfunction of
EEPROM
Cool/Dry: compressor stops
operation, while indoor fan
operates;
Heat: all loads stops operation.
Main board of outdoor unit is damaged.
Flash
once
Flash
once
Refrigerant-
recovery mode
Cool/Dry: compressor and
outdoor fan stops operation, while
indoor fan operates.
Refrigerant recovery. The maintenance personnel operate it
when he is maintaining the unit.
Flash 3
times
Outdoor
ambient
temperature
is open/short-
circuited
Cool/Dry: compressor and
outdoor fan stop operation, while
indoor fan operates;
Heat: all loads stops operation.
1. Temperature sensor is not connected well or damaged; (refer
to Page 69 “Table 1”)
2.Temperature sensor wire of outdoor unit is damaged; short
circuit between the temperature sensor and copper pipe or
outer case
3.Main board of outdoor unit is damaged;
Flash 4
times
Outdoor
condenser
temperature
sensor is open/
short-circuited
Cool/Dry: compressor and
outdoor fan stop operation, while
indoor fan operates;
Heat: after operating for 3mins,
all loads stops operation.
1. Temperature sensor is not connected well or damaged; (refer
to Page 69 “Table 2”)
2. Temperature sensor wire of outdoor unit is damaged; short
circuit between the temperature sensor and copper pipe or
outer case;
3. Main board of outdoor unit is damaged.

39
Display method of indoor unit
Malfunction
name AC status Possible causes
Error
code
Indicator display
Power
indicator
Cool
indicator
Heat
indicator
Flash 5
times
Outdoor air
discharge
temperature
is open/short-
circuited
Complete unit stops operation;
motor of sliding door is cut off
power.
1. The exhaust temperature sensor is not connected well or
damaged. (refer to Page 69 “Table 3”)
2.Temperature sensor wire of outdoor unit is damaged; short
circuit between the temperature sensor and copper pipe or
outer case
3.Main board of outdoor unit is damaged;
Malfunction of
micro switch
Cool/Dry: compressor stops
operation, while indoor fan
operates;
Heat: all loads stops operation.
1. The sliding door is blocked;
2. Malfunction of the photoelectric inspection panel of sliding
door;
Flash 4
times
System is
abnormal
Cool/Dry: all loads stops
operation except indoor fan;
Heat: all loads stops operation.
See Page 53 “High temperature prevention protection; high
power; system isabnormal”
Flash 7
times
Desynchronizing of
compressor
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
See “Page 55 “Desynchronization diagnosis for compressor”
Flash 6
times
PFC protection Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. The power grid quality is bad; AC input voltage uctuates
sharply;
2. Power plug of air conditioner or wiring board or reactor is not
connected reliably;
3. Indoor and outdoor heat exchanger is too dirty, or air inlet/
outlet is blocked;
4. Main board of outdoor unit is damaged.
Flash
14
times
Demagnetization
protection of
compressor
Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The main board of outdoor unit is damaged;
2. Compressor is damaged;
Communication
malfunction
between indoor
unit and inspection
board
Normal operation 1. Poor connection between the indoor unit and the inspection
board.
2.The main board of indoor unit is damaged;
3. The inspection board is damaged;
Malfunction of
humidity sensor
Compressor, outdoor fan and
indoor fan stop operation;
The inspection board is damaged.
High power
protection
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates.
See Page 53 “High temperature prevention protection; high
power; system isabnormal”
Flash
11
times
Start-up failed Cool/Dry: compressor stops,
while indoor fan operates; Heat:
all loads stops operation.
See Page 56 “Malfunction diagnosis for failure startup”
Lost phase Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The main board of outdoor unit is damaged;
2. The compressor is damaged;
3. The connection wire of compressor is not connected well.
Undened
outdoor unit
error
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan stop
operation.
1. Outdoor ambient temperature exceeds the operation range
of unit (eg: less than-20oC or more than 60oC for cooling; more
than 30oC for heating);
2. Are wires of compressor not connected tightly?
3. Failure startup of compressor?
4. Is compressor damaged?
5. Is main board damaged?
Flash
15
times
Over-phase
current
protection of
compressor
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
See “Page 49 “Overload protection of compressor , High
discharge temperature protection of compressor”
Flash
16
times
Communication
malfunction
between the
drive board and
the main board
Cool: compressor and outdoor
fan stops operation; Heat:
compressor and outdoor fan stop
at rst; about 1min later, indoor
fan stops operation;
1. The drive board is damaged;
2. The main board of outdoor unit is damaged;
3. The drive board and the main board is not connected well.
Flash
18
times
Circuit
malfunction
of module
temperature
sensor
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
Replace outdoor control board

40
Display method of indoor unit
Malfunction
name AC status Possible causes
Error
code
Indicator display
Power
indicator
Cool
indicator
Heat
indicator
Flash
19
times
Module
overheating
protection
Cool: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. Air inlet / air outlet of outdoor unit are blocked by lth or dirt;
2. Condenser of outdoor unit is blocked by lth or dirt;
3. IPM screw of main board is not tightened;
4. Main board of outdoor unit is damaged;
Malfunction
of ambient
temperature sensor
of drive board
Cool: compressor, outdoor fan
and indoor fan stop operation;
Heat: compressor and outdoor
fan stop operation at rst; about
1min later, indoor fan stops
operation.
1. The ambient temperature sensor of the drive board is not
connected well;
2. Malfunction of the ambient temperature sensor of drive
board.
Flash
11
times
DC bus voltage is
too high
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. Measure the voltage between position L and position N on
the wiring board (XT). If it’s higher than 265 VAC, please turn
on the unit until the power voltage is decreased to the normal
range;
2. If the AC input is normal, please replace the outdoor control
board.
Flash
21
times
DC bus voltage
is too low
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
1. Measure the voltage between position L and position N on
the wiring board (XT). If it’s lower than 150 VAC, please turn
on the unit until the power voltage is increased to the normal
range;
2. If the AC input is normal, please replace the outdoor control
board.
Flash
17
times
Charging
malfunction of
capacitor
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
See “Page 57 “Charging malfunction of capacitor”
Malfunction of RF
module
Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The connection wire of RF module is not connected well.
2. Malfunction of RF module;
Flash
13
times
Phase current
detection circuit
malfunction of
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan stops
operation.
The control board is damaged
Flash
12
times
Lost phase
protection of
compressor
Cool: compressor and outdoor fan
stop operation; Heat: compressor
and outdoor fan stop operation at
rst; about 1min later, indoor fan
stops operation.
1. The main board of outdoor unit is damaged;
2. The compressor is damaged;
3. The connection wire of compressor is not connected well.
Flash
20
times
DC bus
voltage drop
malfunction
Cool/Dry: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
The power voltage is unstable.
Current
detection
malfunction of
unit
Cool: compressor and outdoor
fan stops operation, while indoor
fan operates; Heat: compressor,
outdoor fan and indoor fan stops
operation.
1. Is the complete unit lacking of refrigerant?
2. There’s malfunction for the circuit of control board of outdoor
unit. Replace the control board of outdoor unit.
4-way valve is
abnormal
This malfunction occurs when
the unit is heating. All loads stops
operation.
1. Power voltage is lower than AC175V;
2. Wiring terminal of 4-way valve is loose or broken;
3. 4-way valve is damaged. Replace the 4-way valve.
Flash
17
times
Malfunction of
zero-crossing
signal of indoor
unit
Compressor, outdoor fan and
indoor fan stop operation.
1. The power is abnormal;
2. Main board of indoor unit is damaged.
Zero-crossing
malfunction of
outdoor unit
Cool: compressor stops
operation, while indoor fan
operates; Heat: all loads stops
operation.
Replace the control board of outdoor unit.

41
Note:
1. As for the models with “ ” display, when there’s malfunction, the dual-8 nixie tube displays the error code, while the
2. The AC status may be different for different models. Please refer to the corresponding manual for the model.
Display method of indoor unit
Malfunction
name AC status Possible causes
Error
code
Indicator display
Power
indicator
Cool
indicator
Heat
indicator
Evaporator
anti-freezing
protection
Not error code, it is the status code in cooling process
Anti cold air
protection
Not error code, it is the status code in heating process
Flash
once/
10s
Defrosting Not error code, it is the status code in heating process

45
Flow Chart of Troubleshooting for Main Malfunctions
1. Troubleshooting for jumper cap
Main check points:
(1) jumper cap (2) control board of indoor unit
N
Y
N
Y
Y
N
NY
N
Y
Display shows “C5”
Check whether the main
board of controller is inserted with
jumper cap.
Insert the equipped
jumper cap
Insert the jump cap
tightly again
Check whether the
jumper cap is not inserted
well.
Replace the jumper
cap with a new one
Eliminate
malfunction
Eliminate
malfunction
Eliminate
malfunction
It's the malfunction of
main board. Replace
the main board with
the a new one.
End

46
2. Communication malfunction
2.1 Communication error of indoor and outdoor unit
Main check points:
(1) Connection wire between indoor unit and outdoor unit
(2) Wiring inside the unit
(3) Communication circuit of control board of indoor unit
(4) Communication circuit of control board of outdoor unit
Y
N
Y
N
N
Y
N
N
Y
N
Y
N
Y
Y
Check whether the
unit has operated normally before
the malfunction occurs.
Check the connection wire of
indoor unit and outdoor unit
according to the wiring diagram.
Check whether the connection
wire of controller inside the
electric box of indoor/outdoor
unit is loose.
Is the
connection correct?
Connect the connection
wire of indoor/outdoor unit
correctly according to the
wiring diagram.
Connect the connection wire of
indoor/outdoor unit correctly
according to the wiring diagram.
Is the connection
wire of electric box is
normal?
Check the communication
circuit of outdoor unit
Is there's problem
for the communication
circuit?
Replace the control
board of outdoor unit.
Replace the control board
of indoor unit.
Start
End
Eliminate
malfunction
Eliminate
malfunction
Eliminate
malfunction
Note: method for checking the communication circuit of inverter split type and floor standing unit: cut off the
communication wires of indoor/outdoor unit, and then measure the voltage between COM and N of the control board
of outdoor unit (DC notch, about 56V)