The document provides detailed installation instructions for DC inverter VRF systems, covering procedures for indoor and outdoor unit installation, piping, electrical wiring, and drainage systems. Key steps include proper placement for maintenance, ensuring gas-tightness, and setting up electrical wiring in compliance with regulations. The document emphasizes careful practices in each stage to prevent future issues and enhance system performance.

1. Installation instruction
ON DC Inverter VRFDEK

2. Installation procedures
Confirm project Check drawing
Install indoor unit Install outdoor unitInstall drainage pipes
Flushing
Install ducts
InsulationVacuum system
Electrical wiring
Commissioning
Welding Pipes laying
Pressure test
Refrigerant charge
Check and hand over

3. 1. Indoor unit installation
2. Outdoor unit installation
3. Piping installation
4. Electrical wiring
5. Commission
6. Main tools
VRF system installation

4. Indoor unit installation
VRF system installation

5. Indoor unit 1.Location
Use plumb bob to determine the location of indoor unit.
Plummet
Plumb bob

6. Indoor unit 2.Hoisting
Use level meter to keep the indoor unit horizontally .
Reduce the running noise
Avoid the condensate water spill from the water collector
Level meter

7. Indoor unit 2.Hoisting
Supports must be strong enough.
The supports should be full thread
booms, and their diameters should
be ≥ 10mm.
Full thread booms
4 Supports
for indoor
unit

8. Indoor unit 2.Hoisting
Dual nuts should be adopted to fix the indoor unit under the ceiling.
Dual nuts Single nut

9. Indoor unit 2.Hoisting
Pack the indoor unit with plastic bag after hoisting to protect them from dust
entering.

10. Outdoor unit installation
VRF system installation

11. The outdoor unit should be placed neatly, and reserve enough space for
maintenance.
The outdoor unit should be installed in the place that is dry, well-ventilation
and close to the indoor units .
Outdoor unit 1.Location

12. ≥1000mm
≥1000mm
150-500mm
≥1000mm
150-500mm
Installation space is shown as below:
Outdoor unit 1.Location

13. If 2 rows of ODUs:
Outdoor unit 1.Location
We suggest: face to face
 Easy maintenance
 No air short-circuit

14. Good duct installation
If the outdoor unit need to side out of the wind by ducting work , it is essential to
remove out the wind grille.
Outdoor unit 1.Location

15. All the outdoor units in one combination should be installed within 5 meters
height difference.
We recommend all the outdoor units installed on the same level if the project
site conditions permit.
Outdoor unit 1.Location

16. The foundation can be made of channel steel or concrete.
Outdoor unit 2.Foundation making
Reserve the space for discharging condensate water from outdoor units.

17. Rubber anti-vibration pads are necessary to avoid vibration.
Rubber Pads
Outdoor unit 2.Foundation making

18. Piping installation
VRF system installation

19. Piping 0.Pipe storing
 For storing the copper pipes:
1. If pipes will be used soon, nozzle should be sealed by plastic bag or tape.
2. If pipes will be stored for a long time, the pipes should be charged into
0.2~0.5MPa Nitrogen and the nozzle should be sealed by welding.

20. Piping 1.Procedures
Piping check
Pipes connection
Flushing
Drainage pipe installation
Gas-tightness test
Insulation
Vacuum dry
Additional refrigerant charge

21. Piping 2.Piping check
 The permitted length and drop difference
Permitted length Pipe
Pipe
length
Pipe total length (Equivalent length)
≤20HP ≤800 m L1+L2+L3+…+
L8+L9
+A+B+C+…+I+J> 20HP ≤1000 m
Max. pipe length（m
）
Actual length ≤175m
L1+L6+L7+L8+L9+J
Equivalent
length
≤190m
Equivalent length from the first branch
to the farthest indoor unit ≤40m L6+L7+L8+L9+J
Drop
height
Drop height between indoor unit and
outdoor unit ≤90m
——
Drop height between indoor units ≤15m

22. Piping 2.Piping check
LdLcLbLa
LBLA
L1
L6
L2
L7 L8 L9
f g h i j
L3 L4 L5
a b c d e
 The longest pipe length ≤ 190 m
Ld+LA+LB+L1+L2+L3+L4+L5+e ≤ 190 m

23. Piping 2.Piping check
LdLcLbLa
LBLA
L1
L6
L2
L7 L8 L9
f g h i j
L3 L4 L5
a b c d e
 The longest pipe length from 1st branch to farthest indoor unit ≤ 40 m
L2+L3+L4+L5+e ≤ 40 m

24. Piping 2.Piping check
LdLcLbLa
LBLA
L1
L6
L2
L7 L8 L9
f g h i j
L3 L4 L5
a b c d e
 Height difference between outdoor unit and indoor unit≤ 90 m
 Height difference between indoor units ≤ 15 m
≤ 15m≤ 90m

25. Piping 2.Piping check
 Select the correct branch joints according to the installation requirement.

26. Piping 3.Pipe hanging
 The distance between the supports of the copper pipes.
 When the liquid pipe and gas pipe are hung up together, it is determined by
the diameter of liquid pipe.
Diameter (mm) ≤ 20 20 ~ 40 ≥ 40
Distance (m) 1 1.5 2
 Record the actual liquid pipe length for future reference when charging
additional refrigerant.

27. Vertically
Horizontally Horizontally
Vertically
Piping 3.Pipe connection
The branch joint of outdoor side must be installed horizontally.
The branch joint of indoor side can be installed horizontally or vertically.

28. Piping 3.Pipe connection
 When install the branch joint horizontally
A
15
°
15
°
A direction
Wrong
Correct
Horizontal
Avoid refrigerant distribution
unbalance.

29. Piping 3.Pipe connection
 Keep enough distance:
1. Between two branch joints ≥1m
2. Between branch joints and indoor unit ≥0.5m
3. From the inlet or outlet of branch joint, there should be straight pipe
with length at least 0.5m
0.5m

30. Piping 3.Pipe connection
 Why?
If the distance is not big enough, it maybe cause unwanted noise
The distribution of the refrigerant is not well balanced in this case

31. Piping 3.Pipe connection
Two branch joints are too close!
There must be no sharp bend (90ºangle )
within 0.5m away from the branch joint.

32. Piping 3.Pipe connection
Do not replace branch joint with T pipe or use the branch joint from other suppliers
->DEKON branch joint is necessary

33. Piping 3.Pipe connection
 Requirement of welding:
 When welding the copper pipe, nitrogen is necessary to protect the copper pipe.
The pressure of the nitrogen is 0.02 MPa
Charge the nitrogen to the copper pipe at the beginning of welding and only
when the copper is fully cooled down, the nitrogen can be removed

34. Piping 3.Pipe connection
2Cu + O2 CuO
High temp.
 Why the Nitrogen is necessary?

35. Piping 3.Pipe connection
 How to charge Nitrogen.
Pressure regulating valve

36. Piping 3.Pipe connection
 How to charge Nitrogen.
N2 will leak from here!

37. Piping 4.Flushing
 Purpose: eliminating dust, water vapor and oxides caused when welding.
 Note: the solid can not be eliminated, so please store the pipes carefully to
prevent the solid entering.
 Method:
1. Flush the pipe with 0.5 MPa Nitrogen
2. Block all the nozzles of the pipes
3. Use your hand to block one of the nozzles
4. When the pressure is too high to block, then
remove your hand
5. Repeat the step 3 and 4 to each nozzle
6. After flushing, seal all the nozzles
Eliminate
Oxid
es
Mois
ture
Dust

38. Piping 4.Flushing
②
⑥ ⑤ ④ ③ ①
 Procedures
From far to near (sequence: ①-②-③-④-⑤-⑥ )
 Note
1. When flushing one pipe, the other pipes need to be sealed.
2. After flushing, remember to seal all the pipes.

39. Piping 5.Gas-tightness test
Before test, gas/liquid
stop valves of outdoor
unit should be closed
well
Exhaust the air in the
system by vacuum
pump
Charge Nitrogen
slowly from both gas
and liquid side at the
same time
 Purpose: check the gas leakage of the system
 Procedures:
 Caution: the gas used must be Nitrogen, but Nitrogen is forbidden to charge
to the outdoor unit’s stop valve directly.

40. Piping 5.Gas-tightness test
 Sequence of pressure test:
Small leakage check: 4.0
MPa more than 24 hours
3rd stage
Big leakage check: 1.5 MPa
more than 3 minutes
2nd stage
Large leakage check: 0.3
MPa more than 3 minutes
1st stage

41. Piping 6.Insulation
Prevent condensate
water adhere to the
gas pipe
Protect people from
hurt of high temp.
Avoid energy loss.
 Purpose:
 Caution: After finish the gastight test, we go on the insulation work of the
refrigerant pipe.

42. Piping 6.Insulation
Pipe diameter Thickness
Φ6.4~15.9mm ≥15mm
Φ15.9~38.1mm ≥20mm
Φ38.1~54.1mm ≥25mm
 Insulation material
The insulation need to be thicker if the ambient is high temperature and
humidity.

43.  The insulation of liquid pipe and gas pipe must be separate
 The insulation work must be done to every part of the refrigerant pipes
Piping 6.Insulation

44. Piping 6.Insulation
Wrong Avoid the dust entering the pipe
 Block the nozzle of the pipe when crossing the insulation material.

45. Piping 6.Insulation
 The gap between two parts should be well insulated by additional insulation
material.
Insulation
Copper pipe
Wrong

46. Piping 7.Vacuum
 Purpose：remove the air and water in the system.
 Necessary tools：vacuum pump (displacement: 4L/s or more)
 Vacuum degree: less than -755mmHg(-0.1MPa)
 Caution: Do not open the valves of outdoor unit when vacuuming ,
and Vacuum dry from liquid side and gas side simultaneously
With check
valve

47. Piping 7.Vacuum
Connect to vacuum pump
When vacuum degree reach to
-0.1MPa(-755mmHg) , continue
vacuuming for another 1 hour
Observe whether the pressure changes
or not (more than 1 hour)
Stop vacuuming
Vacuum the system at least 2h
Outdoor unit
OFF OFF
Gas side
Liquid side
 Vacuum steps:

48.  Additional refrigerant charging procedures:
 Note:
1. Charging excessive refrigerant will cause liquid harmer.
2. Record the actual amount of additional refrigerant for further reference.
Piping 8.Charge refrigerant
Calculate necessary amount of additional refrigerant according to
the diameter and length of liquid pipes1
Make sure the gastight test, vacuum dry, pipe installation has
been finished
2
Charge additional refrigerant to the outdoor unit from gas side
according to the calculation result in the 1st step
3
R410A
UP

49.  Additional refrigerant charged volume:
 Calculate the additional refrigerant according to the diameter and the length
of all liquid pipes connecting to outdoor and indoor units.
Piping 8.Charge refrigerant
Liquid pipe Size
R410A
kg/m
Φ 6.4 0.022
Φ 9.5 0.059
Φ 12.7 0.120
Φ 15.9 0.180
Φ 19.1 0.260
Φ 22.2 0.370
Φ 25.4 0.450

50. Piping 9.Drainage pipe
Condensate water volume (L/h) =
Indoor unit capacity (HP) × 2L/h
Select the diameter
according to the below table
Condensate water volume : V (L/h) I.D (mm) Thickness (mm)
V ≤ 14 Φ 25 3.0
14 ＜ V ≤ 88 Φ 30 3.5
88 ＜ V ≤ 175 Φ 40 4.0
175 ＜ V ≤ 334 Φ 50 4.5
334 ＜ V Φ 80 6.0
 Selection steps:

51.  Caution：the lean of main drainage pipe must be bigger than 1%
 Note
1. If the lean ＜ 1%，then select drainage pipe with bigger diameter
2. The drainage pipe should be independent with other water pipe
3. Never put the drainage pipe together with dirty water pipe
Piping 9.Drainage pipe
Exhaust outlet
Condensate pipe
≥ 1%

52.  Discharge drainage water naturally (without drainage pump):
 If the pressure at the connection of the drain pipe is negative, it needs to be
fixed a drainage trap.
 A plug should be designed to make cleanning easily
Piping 9.Drainage pipe
50mm
50mm
plug
Main drainage pipe

53. Piping 9.Drainage pipe
Increase the height
for easy discharge
 Discharge with drainage pump:
1. 4-way cassette indoor unit has built-in with drainage pump, its pumping
head is 1200mm at most
2. Drainage trap is not necessary when using the drainage pump

54. Piping 9.Drainage pipe
 Note: with drainage pump
Height can not beyond the pump head of drainage pump
Well fixed for this part

55. Piping 9.Drainage pipe
 Typical mistake:
CorrectIncorrect Correct
Drain pipe 3-way pipe
Drain pipe
3-way pipe
Drain pipe
3-way pipe
Avoid horizontal confluence

56. Piping 9.Drainage pipe
Correct wayExhaust outlet should not be upward

57. Piping 9.Drainage pipe
The thickness of insulation material for condensing water pipe is 10mm.
Thin insulation Section of the insulation is too tight

58. Piping 9.Drainage pipe
 Water leakage test
 Check leakage of water pipe
After finished installation of drainage pipe, filled the pipe with water,
waiting for 24 hours to check whether there’s any leakage.
 Check leakage from the indoor unit
Charge water from the check hole of indoor unit to check whether the
water can be exhausted smoothly or not

59. Electrical wiring
VRF system installation

60. Wiring 0.Procedures
Address setting
Power Supply
(Strong power)
Signal wire
(Weak power)

61. Wiring 1.DIP switch setting
 Outdoor address setting
Setting address of outdoor unit through DIP switch SW01
1 2 Description
OFF OFF Master unit
OFF ON Slave 1
ON OFF Slave 2
ON ON Slave 3
SW01
14Hp
Slave 2
16Hp
Slave 1
18Hp
Master

62. Wiring 1.DIP switch setting
 Check the Condensing Fan type setting DIP switch “SW02”
1 2 Definition
OFF OFF Dual DC Fan
OFF ON DC fan left, AC fan right
ON OFF AC fan right, DC fan left
ON ON Dual AC Fan
SW02

63. Wiring 1.DIP switch setting
 Outdoor unit capacity setting
Check the unit capacity setting match the nameplate through DIP switch“ SW03”
SW03
1 2 3 Capacity
OFF OFF OFF 8HP
OFF OFF ON 10HP
OFF ON OFF 12HP
OFF ON ON 14HP
ON OFF OFF 16HP
ON OFF ON 18HP
ON ON OFF 20HP

64. Wiring 1.DIP switch setting
 Outdoor unit type setting
SW04
1 2 3 Definition
OFF OFF OFF DRV Ⅲ
(Factory default)

65. Wiring 1.DIP switch setting
 the quantity of outdoor and indoor unit lock setting
Lock the quantity of outdoor and indoor unit through DIP switch “SW05”
SW05
1 2 3 Definition
OFF OFF OFF Unlock
(Factory default)
ON OFF ON Lock

66. Wiring 1.Address setting
 Indoor address setting by Remote controller
Indoor unit address
NO.
Methold
Press [Sleep] button 8 times within 5
seconds to enter into the interface of
remote parameter change;
Select “parameter NO.” as “1” to enter
the indoor unit addressing mode;
set “Indoor unit address NO.” as
required on site；
press “sending button” to send order;
When hearing buzzer once, it indicates
successful setting

67. Wiring 2.Power supply
Basic requirement
All wires, and electric devices must
be conformed to local standards
All wiring work must be done by
qualified person
Voltage range:
rated voltage
±10%
Independent
power supply
Capacity of
power device is
bigger enough
Well and
reliable PE line

68. Power supply box
Wiring 2.Power supply
Creepage breaker
/Manual switch
3-Phase
380/400/415V
 Power supply for outdoor units

69. Wiring 2.Power supply
 Power supply for indoor units
Notice:
All the indoor units which connected to one outdoor system must be connected to
the same power supply

70. Wiring 2.Power supply
Why should all the indoor units which combined in one system have same power
supply?
→ System is normally running.
→ Some indoor units lose power (plug out or power supply failure) .
→ These indoor units stop, but built-in expansion valves still keep former
opening degree, they can’t close.
→ The outdoor units and other indoor units are still running.
→ The liquid refrigerant flow into the stopped indoor units.
→ This unit’s evaporator will freeze, because their fans are stopped .
→ And the other indoor units can not get enough refrigerant distribution, so the
cooling performance drop down.
Even worse, the liquid refrigerant will directly suck back the compressor, which
cause liquid hammer, damage the compressor.

71. Wiring 2.Power supply
 Creepage breaker selection
According to 1.5-2 times of the total rated current.
 Manual switch selection
As the power is supplied independently, selecting the manual switch and
fuse capacity according to the total capacity.
Total capacity of outdoor units (HP) Manual switch (A) Fuse (A)
10~14 100 75
15~18 100 100
19~28 150 150
29~36 200 200
37~47 300 250
48~50 300 300
52～64 400 400

72. Wiring 2.Power supply
The spec. of the wire is selected
according to the max. total current of
outdoor units
The spec. of the
wire is selected
according to the
max. total current
of indoor units
L N
Indoor unit
Controller
L1L2L3N

73. Wiring 3.Signal wire
 Between outdoor units in one combination
 Between outdoor unit and indoor unit
A,BA,B
Master unit Slave unitSlave unit
A,B A,B

74. Wiring 3.Signal wire
1. Signal wire should be two core shielded twisted pair
2. Keep away from the strong power
3. Non-polar communication
4. Series connection
 Key points

75. Wiring 3.Signal wire
 Key points
5.Signal wire and refrigerant pipe should not be tied together.

76. Commission
VRF system installation

77. Commission 1.Check before start
Power wire / Signal wire
Refrigerant pipe & insulation
Gastight & vacuum dry
1. All the electric wiring is finished?
2. Wire specification are correct?
3. Power wire are well insulation?
4. Well connection?
Additional refrigerant charge
Check valves

78. Commission 1.Check before start
1. Pipes diameters are correct?
2. Pipes are well insulation?
Power wire / Signal wire
Refrigerant pipe & insulation
Gastight & vacuum dry
Additional refrigerant charge
Check valves

79. Commission 1.Check before start
1. Gastight test has been passed?
2. Vacuum dry has been done?
Power wire / Signal wire
Refrigerant pipe & insulation
Gastight & vacuum dry
Additional refrigerant charge
Check valves

80. Commission 1.Check before start
Refrigerant has been charged correctly?
Power wire / Signal wire
Refrigerant pipe & insulation
Gastight & vacuum dry
Additional refrigerant charge
Check valves

81. Commission 1.Check before start
1. Stop valves of outdoor unit are opened?
2. All the fans rotate normally?
Power wire / Signal wire
Refrigerant pipe & insulation
Gastight & vacuum dry
Additional refrigerant charge
Check valves

82. Commission 2.Check Operation
At least 6 hoursPreheat
Error check
Trial operation
Operation test
Hand to user

83. Commission 2.Check Operation
Check if there’s any error code display
on the IDU or ODU?
Preheat
Error check
Trial operation
Operation test
Hand to user

84. Commission 2.Check Operation
Turn-on all indoor units
Preheat
Error check
Trial operation
Operation test
Hand to user

85. Commission 2.Check Operation
1. Check indoor units:
Preheat
Error check
Trial operation
Operation test
Hand to user
Setting 17℃ in cooling mode
 High speed
 Running more than 4 hours
 Check Temp.
-> Temp. difference between air intake
and outlet of each indoor unit should be
bigger than 8℃。

86. Commission 2.Check Operation
2. Check outdoor unit:
 Discharge and suction
temperature of compressors
 Pressure of systems
 Running current
3. Any abnormal noise, vibration
4. Record the operation parameter
Preheat
Error check
Trial operation
Operation test
Hand over to user

87. Commission 2.Check Operation
System pressure and temperature check
R410A
OD35/-,ID27/19 OD43/-,ID32/23
High pressure (MPa) 2.8~3.0 3.4~3.8
Low pressure (MPa) 0.85~1.0 1.0~1.45
Discharge temp.(℃) 70～80 /
Suction temp.(℃) 11～14 /
Indoor air outlet (℃) 12~15 degree (T1 is around 21~27)
temp. difference
between return and
outlet (ΔT)
8~12

88. Commission 2.Check Operation
Daily operation and maintenance
explanation
Preheat
Error check
Trial operation
Operation test
Hand to user

89. Main tools
VRF system installation

90. Outlook Name Scope
Copper pipe cutter R410A
Copper pipe bender R22, R410A
Main tools

91. Outlook Name Scope
Flaring tool R22, R410A
Expander R22, R410A
Main tools

92. Outlook Name Scope
Pressure gauge R410A
Vacuum pump R410A
Main tools
5/16″
Check
valve

93. Outlook Name
Anemometer
acoustic meter
Main tools

94. Outlook Name
Infrared thermometer
Clamp meter
Main tools

95. Outlook Name
Torque spanner
Cutter
Main tools

96. Outlook Name
Electrodrill
Manual hydraulic
crimper
Main tools

97. Thank you!