1. TECHNICAL TRAINING INVERTER-Y
5LCY Series I, Series II & 5MSY
ALGORITHM

2. INDOOR BASIC FUNCTIONS

3. OPERATING MODES
The system has 5 operating modes. The mode selection is done from indoor using handset.
The operating modes are:
Cool
Heat
Fan
Auto
Dry

4. COOL MODE When Tr ≥ Ts - 1.5°C When Tr ≤ Ts - 2°C
Comp, ID Fan and OD Fan ON.
When Tr ≤ Ts - 2°C
Comp and OD Fan OFF.
ID Fan remain ON.
Tr = Room Temperature
Ts = Set Temperature

5. COOL MODE When will Compressor Stop?
When cooling load is too small, even with lowest operation frequency and the room temperature still falling below compressor cut off point, compressor will stop.
Compressor Capacity
Lowest Freq
Time
Tr <= Ts - 2°C
Comp will stop

6. HEAT MODE When Ts > Tr - 1.0°C When Tr ≥ Ts + 1.5°C
Comp, ID Fan and OD Fan ON.
When Tr ≥ Ts + 1.5°C
Comp and OD Fan OFF.
ID Fan remain ON at lowest speed if ID coil ≥ 27°C.
Tr = Room Temperature
Ts = Set Temperature

7. HEAT MODE When will Compressor Stop?
When heating load is too small, even with lowest operation frequency and the room temperature still rising above compressor cut off point, compressor will stop.
Compressor Capacity
Lowest Freq
Time
Tr - Ts ≥ 1.5°C
Comp will stop

8. FAN MODE Only High, Medium and Low fan speeds are allowed.
When changing cool mode to fan mode, the compressor will stop and OD fan stops based on fan OFF control.
Compressor will only ON if the minimum stop time is > 3 minutes and the user change back to cool mode.
Fan speed will maintain same as during fan mode.

9. AUTO MODE For heat pump only Mode switching point:
Heating  Cooling
Tr ≥ Ts + 2.5
Cooling  Heating
Tr ≤ Ts – 2.5
During initial operation
Cooling operation: Tr > Ts
Heating operation: Tr < Ts

10. AUTO MODE – 5MSY Without Priority Room Setting
When more than 1 indoor is operating, priority is given to the first unit that was turned on.
If units that are turned on later to the same operating mode* as the first unit, all units will operate as normal.
Otherwise, they will enter into Standby Mode.
With Priority Room Setting
Unit operation subjected to priority room operating mode.
* - COOL, DRY and FAN mode may be used at the same time
- AUTO mode automatically selects COOL mode or HEAT mode based on Tr.  AUTO mode is available
when selecting the same operation mode as that of the first room to be turned on.

11. ID-OD COMMUNICATION Master by outdoor unit.
Indoor controller board will transmit signal to outdoor controller board every 0.5s. Outdoor unit will response to indoor once the valid data is received.
Indoor
Outdoor
Send Signal
Acknowledge

12. ID-OD COMMUNICATION
If the data communication line between indoor and outdoor disrupted for 15s continuously, compressor will stop, OD fan stop with fan OFF timer. ID LED blinks error.
If the communication resumes within 15s, error code is clear and compressor restarts after 3 minutes.
If the communication does not resume after 15s, unit unable to restart and the error keep blinking.

13. OUTDOOR BASIC FUNCTIONS

14. GENERAL FUNCTIONS

15. THERMISTORS Discharge pipe  Outdoor coil Outdoor air Heat sink
5LCY Series I
5LCY Series II
5MSY
Discharge pipe 
Outdoor coil
Outdoor air
Heat sink
Suction pipe
Gas pipe *
Liquid pipe
* Multiply by number of indoor.

16. THERMISTORS IN 5LCY Series I

17. THERMISTORS IN 5LCY Series II
OD heat exchanger thermistor
OD air thermistor
Suction pipe thermistor
Discharge pipe thermistor

18. THERMISTORS IN 5MSY Liquid pipe thermistor
OD heat exchanger thermistor
Discharge pipe thermistor
Gas pipe thermistor

19. FUNCTIONS OF THERMISTOR
Discharge pipe
Used for discharge superheat (SH) & EXV control. Also used for crankcase heater/ preheating control in 5LCY Series II.
Outdoor coil
Used for defrost control. Also used for inverter current protection control in 5LCY Series II.
Outdoor air
Used for defrost & outdoor fan speed control. Also used for PMV, overall current protection & preheating operation control.
Heat sink
Used for capturing heat sink temperature.
Suction pipe
Used for EXV (SH) & suction pipe SH protection control in heating.
Gas pipe
Used for gas pipe isothermal control in cooling. EXV opening is controlled so that accurate cooling capacity is achieved in each room.
Liquid pipe
Used for sub-cooling control in heating. Actual sub-cooling will be calculated with liquid pipe & max. heat exchanger temperature among all rooms. EXV opening is then adjusted to reach the target sub-cooling.

20. MINIMUM RUN CONTROL To prevent frequent compressor ON/OFF & to
allow pressure equalization
The compressor will be on 3 minutes stand-by after turning OFF before it is allowed to turn ON.
OD fan OFF delay to improve pressure equalization & to prevent refrigerant from entering into evaporator.
Applicable for the whole range

21. AUTO RESTART Factory pre-set.
Allow unit to automatically resume the same operating mode it was in before a power failure.
Note:
Do not use as daily ON/OFF of the unit.
Make sure to turn OFF unit using handset first, before turning OFF power supply to perform maintenance.
Applicable for the whole range

22. 4-WAY VALVE CONTROL
Change over switching is only carried out during operation.
OFF delayed is applied when the coil switches from ON to OFF, i.e. 5LCY Series I - 45 second, 5MSY – 150 second.
Operating mode
4-way valve is
Heat, except for defrost ON
Cool
Dry
Defrost
OFF
Applicable for the whole range

23. DEFROST CYCLE During defrost 5LCY Series I 5LCY Series II 5MSY
Compressor ON
4-way valve
OFF
EXV in operation room
Fixed opening
EXV in operation stop room -
Fixed opening*
Outdoor fan
Indoor fan
Applicable for the whole range

24. DEFROST CONTROL Condition for entering defrost
Compressor minimum run time – 6 minutes OR
Compressor accumulated run time of 45 minutes if OD coil < 3C.
When OD coil < 0C AND OD coil < OD air - 10C.
Condition for terminating defrost
OD coil > 12C or
Total defrost timer of 650 seconds.
Applicable for 5LCY Series I

25. DEFROST CONTROL Condition for entering defrost
Compressor accumulated run time > 25 minutes since the completion of the previous defrost cycle AND
Defrost timer A is met OR outdoor coil temperature is within the defrost request area.
Outdoor ambient,
Ta (C)
Outdoor coil, Tb (C)
-20
-15
-10 -5 15 10 5
Defrost
request area
permit area -1 -3 -7 -9
-11
OD air temperature
A value
> -5 C
2 hours
 -5 C
6 hours
Applicable for 5LCY Series II

26. DEFROST CONTROL Condition for terminating defrost
Defrost time > 10 seconds when Hp > 24.5 bar or
Defrost time > 60 seconds when Tb > 12C or
Defrost time > 540 seconds when Tb > 10C or
Total defrost time of 600 seconds is met.
Applicable for 5LCY Series II

27. DEFROST CONTROL Condition for entering defrost
Compressor minimum run time – 6 minutes OR
Compressor accumulated run time > 38 minutes.
Based on OD coil temperature, output frequency & OD air temperature.
Condition for terminating defrost
Minimum run time of 120 seconds, THEN
Determine based on OD ambient, in the range of 4C ≤ OD coil ≤ 12C OR
Total defrost timer of 650 seconds.
Applicable for 5MSY

28. OUTDOOR FAN CONTROL This control is carried out according to:
When compressor stops, fan OFF delay cut in to expedite pressure equalization & to prevent refrigerant from entering in evaporator.
During defrost.
During cooling/heating operation.
In 5MSY, when no. of indoor decreases.
Applicable for the whole range

29. OUTDOOR FAN CONTROL Determine from
Compressor target rotation: higher fan speed with higher rotation.
Outdoor air temperature.
Cool mode: Higher fan speed with higher outdoor air temperature.
Heat mode: Higher fan speed with lower outdoor air temperature.
When compressor stops, fan OFF delay 30 seconds is carried out
Applicable for 5LCY Series I

30. OUTDOOR FAN CONTROL Control in the function of
Actual outdoor air temperature.
Condensation pressure.
Compression ratio: pressure difference between low & high pressure.
Model
No. of fan
5LCY30ER
Single
5LCY40-60ER
Twin
Applicable for 5LCY Series II

31. OUTDOOR FAN CONTROL Step Cooling Heating 5LCY30ER 5LCY40-60ER M1F M2F
0 rpm 1
200 rpm
250 rpm 2
400 rpm
285 rpm 3
300 rpm
335 rpm 4
360 rpm
325 rpm
395 rpm 5
430 rpm
445 rpm
410 rpm
470 rpm
435 rpm 6
515 rpm
545 rpm
510 rpm
560 rpm
525 rpm 7
620 rpm
660 rpm
625 rpm 8
830 rpm
850 rpm
815 rpm
745 rpm
842 rpm
807 rpm
Applicable for 5LCY Series II

32. OUTDOOR FAN CONTROL
When compressor stops, fan OFF delay 60 seconds is carried out.
When no. of heating room decreases, fan OFF delay 30 seconds applied if outdoor ambient > 10C.
Applicable for 5MSY

33. PMV CONTROL Factory pre-set to be ON. Only active in auto mode.
Minimize excessive cooling and heating based on the predicted mean values (PMV) index specified in ISO7730  reduces annual power consumption without affecting the overall room comfort.
The set point will be moved 1 or 2 C, depending on the actual ID & OD temp. & actual set point, subject to condition changes. The PMV value is calculated every 5 seconds.
Applicable for 5LCY Series II

34. PREHEATING OPERATION CONTROL
Model: 5LCY30ER
Activate after compressor has cut out to avoid refrigerant from dissolving into the compressor oil.
Entering condition:
Compressor stops AND
Power ON for < 6 hours OR > 1 hour after compressor stops, OD ambient temp. is not decreasing & discharge pipe temp. < 70C.
Ending condition:
Thermostat cut in AND
Power ON for > 6 hours OR < 1 hour after compressor stops, ambient temp. is not decreasing & discharge pipe temp. > 75C.
Applicable for 5LCY Series II

35. PREHEATING OPERATION CONTROL
Model: 5MSY
Entering condition:
OD ambient < 10.5C AND
Discharge pipe temp. < 10.5C.
Ending condition:
OD ambient > 12C AND
Discharge pipe temp. < 12C
Applicable for 5MSY

36. CRANKCASE HEATER CONTROL
Model: 5LCY40-60ER
Activate after compressor has cut out to avoid refrigerant from dissolving into the compressor oil. ON
OFF
70 C
75 C
Discharge pipe temperature
Applicable for 5LCY Series II

37. INDOOR COIL FREEZE PREVENTION
Only available in cooling mode.
When the indoor coil temperature < 2°C, the compressor starts to drop the frequency.
This protection will cut in when:
Indoor coil temperature < 0°C for more than 180s. Compressor will stop, OD fan stop after 30s and indoor fan can only run at lowest fan speed.
The unit can only be restarted after 3 minutes.
When the indoor coil temperature > 13°C, the compressor frequency will be reset based on the OD ambient, room and set temperature.
Applicable for the whole range

38. ROTATION REGULATING FUNCTIONS

39. OVERVIEW Upper limit rotation Command Rotation Limit Rotation
Target Rotation
Starting Rotation T
Defrost*
Lower limit rotation
* Defrost control for heat pump model only

40. STARTING ROTATION

41. STARTING CONTROL
To avoid excessive oil discharge from compressor or to promote oil lubrication during startup.
To prevent liquid flood back to the compressor.
To limit starting current.
When compressor starts to rotate from OFF to ON, compressor rotation is set to run gradually to each upper limit at a specific timer setting.

42. STARTING CONTROL Model Max. f 5LCY10DR 68 Hz 5LCY15DR 74 Hz 5LCY20CR
Compressor
rotation, f
Max 55 35 20
Time (min) 1 2 6
Applicable for 5LCY Series I

43. STARTING CONTROL
Normal starting control time is 2-3 minutes & is limited to maximum of 10 minutes. Hz A
Model A
5LCY30ER
79 Hz
5LCY40-60ER
112 Hz
Step 1 1
2-3
Time (min)
Terminating when low pressure < 6 bar OR when the maximum starting time of 10 minutes has been reached if low pressure stays > 6 bar.
Applicable for 5LCY Series II

44. STARTING CONTROL Applicable for 5MSY Compressor rotation, R R3 R2 R1
5MSY20BR
5MSY25/30BR R3 85 80 R2 70 65 R1 55 T1
150
120 T2
180
200 T3
300
470
Compressor
rotation, R R3 R2 R1
Time (seconds) T1 T2 T3
Applicable for 5MSY

45. COMMAND ROTATION

46. COMMAND ROTATION Cut in upon termination of Starting Control.
Achieve capacity control by controlling the compressor rotation based on :
Temperature difference between set and room temperature, T.
Limit Rotation.
Defrost control.

47. COMMAND ROTATION Fuzzy Control
Based on temperature difference, T, current fan speed setting & current indoor operating mode at every 30 seconds interval.
Temperature Difference
Condition 1 T
Condition 2
dT
Tt = Troom - Tset
dT = Tt – Tt-1
Use to set target for compressor frequency change
Compressor frequency is increased or decreased
Applicable for 5LCY Series I

48. COMMAND ROTATION
Compressor frequency is controlled to ensure a constant evaporation temperature in cooling and condensing temperature in heating.
In cooling, target rotation is determined by T& evaporating temperature, Te.
T cool = set temperature – room temperature
Depending on the cooling load, 2C  Target Te  20C
In heating, target rotation is determined by T& condensing temperature, Tc.
T cool = room temperature – set temperature
Depending on the heating load, 42C  Target Tc  54C
Frequency changes at every 20 seconds, maximum at 2 steps/change (6 steps/min)
During abnormal condition, frequency changes at 2 steps but may be at < 20 seconds interval.
Applicable for 5LCY Series II

49. COMMAND ROTATION
The operating frequency will be chosen from a list of fixed frequency settings programmed in the unit’s memory:
Step no.
5LCY30ER
5LCY40-60ER
(Hz) 1
48.0 32 2
52.5 36 3
57.0 41 4
61.5 44 5
66.0 48 6
72.0 52 7
78.0 57 8
85.5 62 9
93.0 67
Step no.
5LCY30ER
5LCY40-60ER
(Hz) 10
100.5 72 11
109.5 78 12
118.5 84 13
127.5 90 14
136.5 94 15
145.5 98 16
154.5
102 17
163.5
107 18
174.0
112
Step no.
5LCY30ER
5LCY40-60ER
(Hz) 19
183.0
117 20
192.0
123 21
201.0
131 22
211.5
139 23
222.0
147 24
232.5
155 25
243.0
164 26
253.5 - 27
265.5
: Max. frequency in cooling
Applicable for 5LCY Series II

50. COMMAND ROTATION PI CONTROL Based on P control, I control & S value.
P control: T of each indoor is calculated at every sampling time of 20s and compressor rotation is adjusted according to the difference from the previously calculated rotation.
I control: if the operating frequency is not changed more than a certain fixed time, a total value of T (T) is obtained:
If T is small  lower frequency.
If T is large  increase frequency.
Applicable for 5MSY

51. COMMAND ROTATION S value:
Indoor unit capacity value which is used for frequency command.
Total S value of each room is used to determine the upper and lower frequency limits.
Indoor capacity
S value
1.0 hp 25
1.5 hp 35
2.0 hp 50
2.5 hp 60
Applicable for 5MSY

52. LIMIT ROTATION

53. LIMIT ROTATION Determine from Upper limit rotation
A minimum value is determine among the upper limits rotation, i.e. protection controls.
Lower limit rotation
A maximum value is determine among the lower limits rotation, i.e. protection controls.

54. OVERVIEW Generally, compressor rotation is controlled within 4
zones: stop, drop, keep, up and reset subjected to a
particular operating temperature/current/pressure.
Zone
Control
Stop
Compressor is stopped when a certain limit reaches the stop zone for abnormality correction.
Drop
Frequency will be dropped with a timer setting.
Keep
Frequency is maintained at lower/upper limit. Up
Frequency will be increased with a timer setting.
Reset
Frequency lower/upper limit is canceled and returned to command rotation.

55. LOW PRESSURE PROTECTION
To prevent abnormal low pressure in the system.
Detected by low pressure sensor.
Mode
Activation
Compressor stop
Reset
5LCY30ER
Cooling
LP < 1.2bar
LP < 1.2bar & after 5 min elapsed
LP > 1.5bar & 30 sec elapsed OR
 10 times stopping in 200 min
Heating
LP < 1.2bar AND
Within 10 min after defrost OR LPS activates continuously for 5 min
LP > 1.5bar & 60 sec elapsed OR
5LCY40-60ER
LP < 4.9bar
LP < 0.5bar OR LP < 1bar for 5 min
LP > 5.9bar & after 30 second elapsed OR
LP < 1.5bar AND
Within 5 min after startup OR within 10 min after defrost OR *
*Within 10 min after defrost & LP < 1bar 5 min continuous & LP < 0.5bar
Applicable for 5LCY Series II

56. HIGH PRESSURE PROTECTION
To prevent high pressure in the system.
Compressor operating frequency is adjusted based on upper limit of coil temperature (5SLY series I & 5MSY) or system pressure (5LCY series II).
Applicable for the whole range

57. HIGH PRESSURE PROTECTION
Applicable for 5LCY Series I

58. HIGH PRESSURE PROTECTION
The compressor frequency is adjusted based on coil temperature:
During cooling mode – outdoor coil temperature.
During heating mode – indoor coil temperature.
This protection is activated when the coil temperature > 64°C, the compressor stop and OD fan stop after 30s.
The unit can only be restarted after 3 minutes.
Applicable for 5LCY Series I

59. HIGH PRESSURE PROTECTION
During cooling operation
Stop zone
> 1 min or HPS activates I
> D: compressor rotation set to A D
Frequency
drop zone C F
Up zone
+ 1 step/5 min H
+ 1 step/min G
Reset zone A C D F G H I
5LCY30ER
118.5 Hz
32.2 bar
33.2 bar
31.8 bar
29.4 bar
30.8 bar
39.2 bar
5LCY40-60ER
62 Hz
36.8 bar
37.7 bar
36.3 bar
34.3 bar
35.8 bar
Applicable for 5LCY Series II

60. HIGH PRESSURE PROTECTION
During heating operation
OR HPS activates
Stop zone I
> D: compressor rotation set to B C
32.4 bar
30 seconds elapsed
Reset zone B C I
5LCY30ER
118.5 Hz
32.2 bar
39.2 bar
5LCY40-60ER
62 Hz
36.8 bar
Applicable for 5LCY Series II

61. HIGH PRESSURE PROTECTION
The compressor rotation is adjusted based on calculated high pressure (HP) value from the low pressure, power input & compressor frequency.
This protection is activated when HP > C. HP switch (HPS) will be activated or HP > I (cooling for 1 min)  compressor stops.
HP switch opens at 40 bar (tolerance +0/-0.15)
HP switch closes at 30 bar (tolerance +/-0.15)
Error code indication (E3) will cut in when compressor stops 16 (cooling) /15 (heating) times in 300 min.
Applicable for 5LCY Series II

62. HIGH PRESSURE PROTECTION
Drop zone
59C
Remain zone
Reset zone
56C
Based on coil temperature:
During cooling mode – outdoor coil temperature.
During heating mode – indoor coil temperature.
This protection is activated when coil temperature among the operating rooms > 60°C.
The system stops after staying in the frequency reduce zone for 2 minutes.
Applicable for 5MSY

63. DISCHARGE PIPE TEMPERATURE CONTROL
Used as a measure of the compressor’s internal temperature.
Compressor frequency is control to keep this temperature from going up further when it rises above a certain level.
Applicable for the whole range

64. DISCHARGE PIPE TEMPERATURE CONTROL
Discharge temperature
Stop zone
(120C)
(111C)
Drop zone
(109C)
Frequency
keep zone
(107C)
Reset zone
Note: 5LCY (5MSY)
Applicable for 5LCY Series I & 5MSY

65. DISCHARGE PIPE TEMPERATURE CONTROL
If compressor discharge temperature >102°C (111°C) for the first time, this control starts and set the current frequency as upper limit. At the same time, running frequency start to reduce by 1 step and so on, until temperature falls between 99°C (109°C)and 90°C (107°C) – at the maintain zone.
This protection is activated when the compressor discharge temperature > 110°C (120°C). The compressor will stop and considered trip.
If the compressor discharge temperature < 90°C (107°C), the compressor frequency will be reset based on the OD ambient, set and room temperature.
Applicable for 5LCY Series I & 5MSY

66. DISCHARGE PIPE TEMPERATURE CONTROL
Normal operation
- 1 step/20 second
Set to H Hz
Compressor stop
Td > BC
Td  CC 5 min continuous & 300 second elapsed
OR Td > DC
Td  EC G min continuous
OR Td  FC
+ 1 step/60 second
Td  BC
 10 times in 200 min
Td < AC OR
Td  B C & 5 min elapsed
Td < BC & Upper limit f = max f A B C D E F G H
5LCY30ER
100C
105C
110C
120C
125C
15min
118.5Hz
5LCY40-60ER
115C
135C
10min
62Hz
Applicable for 5LCY Series II

67. OVERALL CURRENT CONTROL
To monitor the overall current and to restrict the compressor upper limit rotation in order to prevent circuit breakers from exceeding the rated capacity.
Detected during compressor running.
Applicable for the whole range

68. OVERALL CURRENT CONTROL
Current (A)
Model L1
5LCY10DR
9.5A
5LCY15DR
10.0A
5LCY20CR
12.0A
5LCY25CR
5MSY20BR
20.0A
5MSY25BR
19.5A
5MSY30BR
Stop zone L1
Frequency
reduce zone L2
Frequency
remain zone L3
Reset zone
Applicable for 5LCY Series I & 5MSY

69. OVERALL CURRENT CONTROL
When the input current for running compressor exceeds L2, running frequency will be reduced by 1 step. If current still exceeds L2, frequency will be reduced by another 1 step until total current falls between L2 and L3.
This protection cut in when the input current exceeds L1 for 2 seconds – 5LCY series I or 2.5 seconds – 5MSY. Compressor will stop and it is considered total current overload.
If input current <L3, the compressor frequency is reset based on the OD ambient, set and room temperature.
Applicable for 5LCY Series I & 5MSY

70. OVERALL CURRENT CONTROL
To monitor overall current and restrict the compressor upper limit (CULR)
rotation to prevent circuit breakers from exceeding the rated capacity.
Normal operation
- OD unit current  A AND f = max. rotation
OD unit current > A
OD unit current < A
f -1 step/10s
f +1 step/120s
OD unit current > A
Upper Limit Current (A) A
5LCY30ER
5LCY40-60ER U
16.5
24.0 B C
13.4
23.0 D
10.0
16.0 U B C D 25 28 43 50
OD air temperature
Applicable for 5LCY Series II

71. OIL RECOVERY CONTROL
When the compressor operates for a certain duration at low frequency, the oil level in the compressor may become low due to incomplete oil return.
To prevent damage to the compressor or compressor lock due to low oil lever.
To promote refrigerant flow to carry the oil back to the compressor.
Applicable for the whole range

72. OIL RECOVERY CONTROL Entering condition: OR
Compressor rotation < 35 Hz, at the end of a 20 minutes timer: set lower limit rotation to 35 Hz & EXV opening is fixed at current opening + 50 pulse. This control is reset when rotation > 35 Hz. OR
Compressor rotation > 35 Hz, for every 120 minutes: current rotation is remained & EXV is fixed at current opening + 50 pulse. This control is reset after 5 minutes.
Applicable for 5LCY Series I

73. OIL RECOVERY CONTROL
This operation only cut in during cooling mode, compressor frequency will be increased to a certain level for a duration of 5 minute.
Enter condition: f  63Hz for 5 minute continuously and system will calculate the oil discharge amount.
During heating mode, oil return is guaranteed by the defrost operation.
Applicable for 5LCY Series II

74. OIL RECOVERY CONTROL
When one of the cooling room stops, the EXV opening will be set to open for a certain time at a specified interval so that the oil may not accumulate in the cooling stopped room.
During cooling operation, for every 1 hour of continuous operation, the EXV in the operation stopped room will be set to opened for 80 pulses for a specified time.
Applicable for 5MSY

75. THANK YOU
&
Q & A