Daikin VRV - WII User manual

SiUS30 - 604
Water Cooled Inverter Series
— Heat Pump / Heat Recovery-60Hz —

SiUS30-604
Table of Contents i
Water Cooled
Inverter Series
1. Introduction ............................................................................................... vii
1.1 Safety Cautions ...........................................................................................vii
1.2 PREFACE ....................................................................................................xi
Part 1 General Information .............................................................. 1
1. Features ......................................................................................................2
1.1 Design flexibility............................................................................................ 3
1.2 Easy installation ........................................................................................... 5
1.3 Energy saving............................................................................................... 6
1.4 Enhanced usability ....................................................................................... 7
1.5 Outside unit lineup........................................................................................ 8
2. Model Names ..............................................................................................9
2.1 Water Cooled System .................................................................................. 9
3. External Appearance.................................................................................10
3.1 Indoor Units ................................................................................................ 10
3.2 Outside Units.............................................................................................. 11
4. Combination of Outside Units ...................................................................12
5. Capacity Range.........................................................................................13
Part 2 Specifications ..................................................................... 15
1. Specifications ............................................................................................16
1.1 Outside Units.............................................................................................. 16
1.2 BS Units ..................................................................................................... 23
1.3 Indoor Units ................................................................................................ 24
Part 3 Refrigerant Circuit .............................................................. 37
1. Refrigerant Circuit .....................................................................................38
1.1 RWEYQ60MTJU / RWEYQ72MTJU / RWEYQ84MTJU............................ 38
1.2 BSVQ36, 60M ............................................................................................ 40
2. Functional Parts Layout ............................................................................41
2.1 RWEYQ60MTJU / RWEYQ72MTJU / RWEYQ84MTJU............................ 41
3. Refrigerant Flow for Each Operation Mode...............................................43
3.1 In Case of Heat Pump Connection............................................................. 43
3.2 In Case of Heat Recovery Connection
(One Outside Unit Installation) ................................................................... 45
3.3 In Case of Heat Recovery Connection
(3 Outside units Connection.)..................................................................... 49

SiUS30-604
ii Table of Contents
Part 4 Function............................................................................... 53
1. Function General.......................................................................................55
1.1 Symbol ....................................................................................................... 55
1.2 Operation Mode.......................................................................................... 56
1.3 Normal Operation ....................................................................................... 57
1.4 BS unit & Indoor unit operation mode detail............................................... 58
2. Stop...........................................................................................................59
2.1 Stopping Operation .................................................................................... 59
3. Standby .....................................................................................................61
3.1 Restart Standby.......................................................................................... 61
3.2 Crankcase Heater Control.......................................................................... 61
4. Startup Control ..........................................................................................62
4.1 Cooling Start-up Control............................................................................. 62
4.2 Heating Start-up Control............................................................................. 63
4.3 Pressure Equalizing Control....................................................................... 64
5. Normal Control ..........................................................................................65
5.1 Compressor Control ................................................................................... 65
5.2 Electronic Expansion Valve Control ........................................................... 67
5.3 Heat Exchange Mode in Heating Operation or
Simultaneous Cooling / Heating Operation ................................................ 68
6. Protection Control .....................................................................................70
6.1 High Pressure Protection Control............................................................... 70
6.2 Low Pressure Protection Control................................................................ 71
6.3 Discharge Pipe Protection Control ............................................................. 73
6.4 Inverter Protection Control ......................................................................... 74
6.5 Cooling Fan Control ................................................................................... 75
7. Special Operation......................................................................................76
7.1 Oil Return Operation .................................................................................. 76
7.2 Oil Return Operation of Water Heat Exchanger ......................................... 78
7.3 Pump-down Residual Operation Control.................................................... 79
7.4 Refrigerant Drift Prevention........................................................................ 81
8. Other Control.............................................................................................82
8.1 Outside Unit Rotation ................................................................................. 82
9. Outline of Control (Indoor Unit) .................................................................83
9.1 Drain Pump Control.................................................................................... 83
9.2 Louver Control for Preventing Ceiling Dirt.................................................. 85
9.3 Thermostat Sensor in Remote Controller................................................... 86
9.4 Thermostat Control While in Normal Operation ......................................... 88
9.5 Thermostat Control in Dry Operation ......................................................... 88
9.6 Electronic expansion Valve Control............................................................ 89
9.7 Hot Start Control (In Heating Operation Only)............................................ 89
9.8 Heater Control ............................................................................................ 90
9.9 List of Swing Flap Operations .................................................................... 91
9.10 Freeze Prevention ...................................................................................... 92

SiUS30-604
Table of Contents iii
Part 5 Test Operation .................................................................... 93
1. Test Operation ..........................................................................................94
1.1 Procedure and Outline ............................................................................... 94
2. Outside Unit PC Board Layout ..................................................................98
3. Field Setting ..............................................................................................99
3.1 Field Setting from Remote Controller ......................................................... 99
3.2 Field Setting from Outside Unit ................................................................ 110
Part 6 Troubleshooting ................................................................ 137
1. Troubleshooting by Remote Controller ...................................................140
1.1 The INSPECTION / TEST Button............................................................. 140
1.2 Self-diagnosis by Wired Remote Controller ............................................. 141
1.3 Self-diagnosis by Wireless Remote Controller ......................................... 142
1.4 Operation of the Remote Controller’s Inspection /
Test Operation Button .............................................................................. 144
1.5 Remote Controller Service Mode ............................................................. 145
1.6 Remote Controller Self-Diagnosis Function ............................................. 147
2. Troubleshooting by Indication on the Remote Controller ........................154
2.1 “A0” Indoor Unit: Error of External Protection Device ............................... 154
2.2 “A1” Indoor Unit: PC Board Defect............................................................. 155
2.3 “A3” Indoor Unit: Malfunction of Drain Level Control System (S1L) .......... 156
2.4 “A6” Indoor Unit: Fan Motor (M1F) Lock, Overload................................... 158
2.5 “A7” Indoor Unit: Malfunction of Swing Flap Motor (MA) ........................... 162
2.6 “A9” Indoor Unit: Malfunction of Moving Part of
Electronic Expansion Valve (Y1E)............................................................ 164
2.7 “AF” Indoor Unit: Drain Level above Limit.................................................. 166
2.8 “AJ” Indoor Unit: Malfunction of Capacity Determination Device .............. 167
2.9 “C4” Indoor Unit: Malfunction of Thermistor (R2T) for
Heat Exchanger........................................................................................ 168
2.10 “C5” Indoor Unit: Malfunction of Thermistor (R3T) for Gas Pipes.............. 169
2.11 “C9” Indoor Unit: Malfunction of Thermistor (R1T) for Suction Air............. 170
2.12 “CJ” Indoor Unit: Malfunction of Thermostat Sensor in
Remote Controller .................................................................................... 171
2.13 “E1” Outside Unit: PC Board Defect........................................................... 172
2.14 “E3” Outside Unit: Actuation of High Pressure Switch............................... 173
2.15 “E4” Outside Unit: Actuation of Low Pressure Sensor............................... 175
2.16 “E5”Compressor Motor Lock .................................................................... 177
2.17 “E9” Outside Unit: Malfunction of Moving Part of
Electronic Expansion Valve (Y1E, Y3E)................................................... 179
2.18 “F3” Outside Unit: Abnormal Discharge Pipe Temperature....................... 181
2.19 “F6”Refrigerant Overcharged ................................................................... 182
2.20 “HJ” Malfunction of Water system ............................................................. 184
2.21 “J3” Outside Unit: Malfunction of Discharge Pipe Thermistor (R3T)......... 186
2.22 “J4” Malfunction of Heat Exchanger Gas Pipe Thermistor (R4T) ............. 187
2.23 “J5” Outside Unit: Malfunction of Thermistor (R2T) for Suction Pipe........ 188
2.24 “J7” Malfunction of Liquid Pipe Thermistor (R6T) ..................................... 189

SiUS30-604
iv Table of Contents
2.25 “J9” Malfunction of Sub Cooling Heat Exchanger Outlet Thermistor
(R5T) ........................................................................................................ 190
2.26 “JA” Outside Unit: Malfunction of Discharge Pipe Pressure Sensor ......... 191
2.27 “JC” Outside Unit: Malfunction of Suction Pipe Pressure Sensor.............. 193
2.28 “L1” Outdoor Unit: Malfunction of PC Board .............................................. 195
2.29 “L4” Outside Unit: Malfunction of Inverter Radiating Fin
Temperature Rise (R1T) .......................................................................... 196
2.30 “L5” Outside Unit: Inverter Compressor Abnormal.................................... 197
2.31 “L8” Outside Unit: Inverter Current Abnormal ........................................... 198
2.32 “L9” Outside Unit: Inverter Start up Error .................................................. 200
2.33 “LC” Outside Unit: Malfunction of Transmission between
Inverter and Control PC Board................................................................. 201
2.34 “P1” Outside Unit: Inverter Over-Ripple Protection .................................... 203
2.35 “P4” Outside Unit: Malfunction of Inverter Radiating Fin
Temperature Sensor ................................................................................ 205
2.36 “PJ” Outdoor Unit: Faulty Field Setting after Replacing Main PC Board or
Faulty Combination of PC Board.............................................................. 206
2.37 “UO” Low Pressure Drop Due to Refrigerant Shortage or
Electronic Expansion Valve Failure.......................................................... 207
2.38 “U1”Reverse Phase, Open Phase............................................................. 209
2.39 “U2” Power Supply Insufficient or Instantaneous Failure .......................... 210
2.40 “U3”Check Operation not Executed.......................................................... 212
2.41 “U4”Malfunction of Transmission between Indoor Units........................... 213
2.42 “U5”Malfunction of Transmission between Remote Controller and
Indoor Unit................................................................................................ 215
2.43 “U7” Malfunction of Transmission between Outside Units......................... 216
2.44 “U8”Malfunction of Transmission between Master and
Slave Remote Controllers ........................................................................ 218
2.45 “U9” Malfunction of Transmission between Indoor and
Outside Units in the Same System........................................................... 219
2.46 “UA” Indoor & Outside Units and Remote Controller
Combination Failure ................................................................................. 221
2.47 “UC” Address Duplication of Centralized Controller................................... 223
2.48 “UE”Malfunction of Transmission between Centralized Controller and
Indoor Unit................................................................................................ 224
2.49 “UF” Refrigerant System not Set, Incompatible Wiring/Piping................... 226
2.50 “UH” Malfunction of System, Refrigerant System Address Undefined....... 227
3. Troubleshooting (OP: Central Remote Controller) ..................................229
3.1 “M1”PC Board Defect ................................................................................ 229
3.2 “M8” Malfunction of Transmission between Optional Controllers for
Centralized Control................................................................................... 230
3.3 “MA” Improper Combination of Optional Controllers for
Centralized Control................................................................................... 232
3.4 “MC” Address Duplication, Improper Setting .............................................. 234
4. Troubleshooting (OP: Schedule Timer)...................................................235
4.1 “UE” Malfunction of Transmission between Centralized Controller and
Indoor Unit................................................................................................ 235
4.2 “M1” PC Board Defect ................................................................................ 237

SiUS30-604
Table of Contents v
4.3 “M8” Malfunction of Transmission between Optional Controllers for
Centralized Control................................................................................... 238
4.4 “MA” Improper Combination of Optional Controllers for
Centralized Control................................................................................... 240
4.5 “MC”Address Duplication, Improper Setting .............................................. 242
5. Troubleshooting (OP: Unified ON/OFF Controller) .................................243
5.1 Operation Lamp Blinks ............................................................................. 243
5.2 Display “Under Host Computer Integrate Control” Blinks
(Repeats Single Blink).............................................................................. 245
5.3 Display “Under Host Computer Integrate Control” Blinks
(Repeats Double Blink) ............................................................................ 248
Part 7 Procedure for Mounting /
Dismounting of Switch Box............................................... 255
1. Procedure for Mounting / Dismounting of Switch Box.............................256
1.1 Procedure for Dismounting....................................................................... 256
1.2 Procedure for Mounting............................................................................ 256
Part 8 Appendix............................................................................ 259
1. Piping Diagrams......................................................................................260
1.1 Outside Units............................................................................................ 260
1.2 Indoor Unit................................................................................................ 261
1.3 BS Unit ..................................................................................................... 263
2. Wiring Diagrams......................................................................................264
2.1 Outside Unit.............................................................................................. 264
2.2 Outside Unit Field Wiring.......................................................................... 265
2.3 Indoor Unit................................................................................................ 267
2.4 BS Unit ..................................................................................................... 271
3. List of Electrical and Functional Parts .....................................................272
3.1 Outside Unit.............................................................................................. 272
3.2 Indoor Side ............................................................................................... 273
4. Option List ...............................................................................................276
4.1 Optional Accessories................................................................................ 276
5. Thermistor Resistance / Temperature Characteristics............................278
6. Pressure Sensor .....................................................................................280
7. Method of Replacing the Inverter’s Power Transistors and
Diode Modules ........................................................................................281
7.1 Method of Replacing the Inverter’s Power Transistors and
Diode Modules ......................................................................................... 281
Part 9 Precautions for New Refrigerant (R-410A) ....................... 283
1. Precautions for New Refrigerant (R-410A) .............................................284
1.1 Outline ...................................................................................................... 284
1.2 Service Tools............................................................................................ 286

SiUS30-604
vi Table of Contents
Index ................................................................................................ i
Drawings & Flow Charts ................................................................... v

SiUS30-604 Introduction
vii
1. Introduction
1.1 Safety Cautions
Cautions and
Warnings
Be sure to read the following safety cautions before conducting repair work.
The caution items are classified into “ Warning” and “ Caution”. The “ Warning”
items are especially important since they can lead to death or serious injury if they are not
followed closely. The “ Caution” items can also lead to serious accidents under some
conditions if they are not followed. Therefore, be sure to observe all the safety caution items
described below.
About the pictograms
This symbol indicates an item for which caution must be exercised.
The pictogram shows the item to which attention must be paid.
This symbol indicates a prohibited action.
The prohibited item or action is shown inside or near the symbol.
This symbol indicates an action that must be taken, or an instruction.
The instruction is shown inside or near the symbol.
After the repair work is complete, be sure to conduct a test operation to ensure that the
equipment operates normally, and explain the cautions for operating the product to the
customer.
1.1.1 Caution in Repair
Warning
Be sure to disconnect the power cable plug from the plug socket before
disassembling the equipment for a repair.
Working on the equipment that is connected to a power supply can cause an
electrical shock.
If it is necessary to supply power to the equipment to conduct the repair or
inspecting the circuits, do not touch any electrically charged sections of the
equipment.
If the refrigerant gas discharges during the repair work, do not touch the
discharging refrigerant gas.
The refrigerant gas can cause frostbite.
When disconnecting the suction or discharge pipe of the compressor at the
welded section, release the refrigerant gas completely at a well-ventilated place
first.
If there is a gas remaining inside the compressor, the refrigerant gas or
refrigerating machine oil discharges when the pipe is disconnected, and it can
cause injury.
If the refrigerant gas leaks during the repair work, ventilate the area. The
refrigerant gas can generate toxic gases when it contacts flames.
The step-up capacitor supplies high-voltage electricity to the electrical
components of the outside unit.
Be sure to discharge the capacitor completely before conducting repair work.
A charged capacitor can cause an electrical shock.
Do not start or stop the air conditioner operation by plugging or unplugging the
power cable plug.
Plugging or unplugging the power cable plug to operate the equipment can cause
an electrical shock or fire.

Introduction SiUS30-604
viii
1.1.2 Cautions Regarding Products after Repair
Caution
Do not repair the electrical components with wet hands.
Working on the equipment with wet hands can cause an electrical shock.
Do not clean the air conditioner by splashing water.
Washing the unit with water can cause an electrical shock.
Be sure to provide the grounding when repairing the equipment in a humid or wet
place, to avoid electrical shocks.
Be sure to turn off the power switch and unplug the power cable when cleaning
the equipment.
The internal fan rotates at a high speed, and cause injury.
Do not tilt the unit when removing it.
The water inside the unit can spill and wet the furniture and floor.
Be sure to check that the refrigerating cycle section has cooled down sufficiently
before conducting repair work.
Working on the unit when the refrigerating cycle section is hot can cause burns.
Use the welder in a well-ventilated place.
Using the welder in an enclosed room can cause oxygen deficiency.
Warning
Be sure to use parts listed in the service parts list of the applicable model and
appropriate tools to conduct repair work. Never attempt to modify the equipment.
The use of inappropriate parts or tools can cause an electrical shock, excessive
heat generation or fire.
When relocating the equipment, make sure that the new installation site has
sufficient strength to withstand the weight of the equipment.
If the installation site does not have sufficient strength and if the installation work
is not conducted securely, the equipment can fall and cause injury.
Be sure to install the product correctly by using the provided standard installation
frame.
Incorrect use of the installation frame and improper installation can cause the
equipment to fall, resulting in injury.
For integral units
only
Be sure to install the product securely in the installation frame mounted on a
window frame.
If the unit is not securely mounted, it can fall and cause injury.
For integral units
only

SiUS30-604 Introduction
ix
1.1.3 Inspection after Repair
Be sure to use an exclusive power circuit for the equipment, and follow the
technical standards related to the electrical equipment, the internal wiring
regulations and the instruction manual for installation when conducting electrical
work.
Insufficient power circuit capacity and improper electrical work can cause an
electrical shock or fire.
Be sure to use the specified cable to connect between the indoor and outdoor
units. Make the connections securely and route the cable properly so that there is
no force pulling the cable at the connection terminals.
Improper connections can cause excessive heat generation or fire.
When connecting the cable between the indoor and outside units, make sure that
the terminal cover does not lift off or dismount because of the cable.
If the cover is not mounted properly, the terminal connection section can cause an
electrical shock, excessive heat generation or fire.
Do not damage or modify the power cable.
Damaged or modified power cable can cause an electrical shock or fire.
Placing heavy items on the power cable, and heating or pulling the power cable
can damage the cable.
Do not mix air or gas other than the specified refrigerant (R-410A) in the refrigerant
system.
If air enters the refrigerating system, an excessively high pressure results, causing
equipment damage and injury.
If the refrigerant gas leaks, be sure to locate the leak and repair it before charging
the refrigerant. After charging refrigerant, make sure that there is no refrigerant
leak.
If the leak cannot be located and the repair work must be stopped, be sure to
perform pump-down and close the service valve, to prevent the refrigerant gas
from leaking into the room. The refrigerant gas itself is harmless, but it can
generate toxic gases when it contacts flames, such as fan and other heaters,
stoves and ranges.
When replacing the coin battery in the remote controller, be sure to disposed of
the old battery to prevent children from swallowing it.
If a child swallows the coin battery, see a doctor immediately.
Warning
Caution
Installation of a leakage breaker is necessary in some cases depending on the
conditions of the installation site, to prevent electrical shocks.
Do not install the equipment in a place where there is a possibility of combustible
gas leaks.
If a combustible gas leaks and remains around the unit, it can cause a fire.
Be sure to install the packing and seal on the installation frame properly.
If the packing and seal are not installed properly, water can enter the room and
wet the furniture and floor.
For integral units
only
Warning
Check to make sure that the power cable plug is not dirty or loose, then insert the
plug into a power outlet all the way.
If the plug has dust or loose connection, it can cause an electrical shock or fire.

Introduction SiUS30-604
x
1.1.4 Using Icons
Icons are used to attract the attention of the reader to specific information. The meaning of each
icon is described in the table below:
1.1.5 Using Icons List
If the power cable and lead wires have scratches or deteriorated, be sure to
replace them.
Damaged cable and wires can cause an electrical shock, excessive heat
generation or fire.
Do not use a joined power cable or extension cable, or share the same power
outlet with other electrical appliances, since it can cause an electrical shock,
excessive heat generation or fire.
Warning
Caution
Check to see if the parts and wires are mounted and connected properly, and if
the connections at the soldered or crimped terminals are secure.
Improper installation and connections can cause excessive heat generation, fire
or an electrical shock.
If the installation platform or frame has corroded, replace it.
Corroded installation platform or frame can cause the unit to fall, resulting in injury.
Check the grounding, and repair it if the equipment is not properly grounded.
Improper grounding can cause an electrical shock.
Be sure to measure the insulation resistance after the repair, and make sure that
the resistance is 1 Mohm or higher.
Faulty insulation can cause an electrical shock.
Be sure to check the drainage of the indoor unit after the repair.
Faulty drainage can cause the water to enter the room and wet the furniture and
floor.
Icon Type of
Information Description
Note:
Note A “note” provides information that is not indispensable, but may
nevertheless be valuable to the reader, such as tips and tricks.
Caution
Caution A “caution” is used when there is danger that the reader, through
incorrect manipulation, may damage equipment, loose data, get an
unexpected result or has to restart (part of) a procedure.
Warning
Warning A “warning” is used when there is danger of personal injury.
Reference A “reference” guides the reader to other places in this binder or in
this manual, where he/she will find additional information on a
specific topic.

SiUS30-604 Introduction
xi
1.2 PREFACE
Thank you for your continued patronage of Daikin products.
This is the new service manual for Daikin’s water cooled VRV System.
Daikin offers a wide range of models to respond to building and office air conditioning needs.
We are confident that customers will be able to find the models that best suit their needs.
This service manual contains information regarding the servicing of water cooled VRV System.
January 2007
After Sales Service Division

Introduction SiUS30-604
xii

SiUS30-604
General Information 1
Part 1
General Information
1. Features ......................................................................................................2
1.1 Design flexibility............................................................................................ 3
1.2 Easy installation ........................................................................................... 5
1.3 Energy saving............................................................................................... 6
1.4 Enhanced usability ....................................................................................... 7
1.5 Outside unit lineup........................................................................................ 8
2. Model Names ..............................................................................................9
2.1 Water Cooled System .................................................................................. 9
3. External Appearance.................................................................................10
3.1 Indoor Units ................................................................................................ 10
3.2 Outside Units.............................................................................................. 11
4. Combination of Outside Units ...................................................................12
5. Capacity Range.........................................................................................13

Features SiUS30-604
2General Information
1. Features
Cooling tower Boiler (for heating)
This unique system can perform as heat pump or heat recovery to any
suitable application.
VRV-WII
Cutting-edge technologies
The compact unit is packed with the latest technologies.
Water-pipe-less
internal structure
Heat exchanger
Evaporating/condensing ability
Reluctance DC
scroll compressor
By adoption of the Sine Wave which
smoothes rotation of motor,
operation efficiency is improved
sharply.
Smooth sine wave DC Inverter
Reluctance
DC motor
Scrolling
High thrust mechanism
A water cooled intelligent
individual air conditioning system
suitable for
tall multistoried buildings.
Water piping
Cooling tower (Closed type),
boiler
Refrigerant piping
To Indoor units

SiUS30-604 Features
General Information 3
1.1 Design flexibility
Enhanced design flexibility
Indoor installation
The system can tolerate water pressure up to 284.2psi.
VRV-WII
Cooling tower (Closed type)
Indoor installation
VRV-WII
Water cooled VRV II uses water as its heat source so is eminently suitable for tall multistory or
large buildings because the system can tolerate up to 284.2psi water pressure. Furthermore, if
the currently installed heat source water temperature is between 50°F and 113°F, it may be
possible to use the existing water pipe work and heat source. This alone makes it an ideal
system solution for building refurbishment projects.
*Prior consultation is necessary about the heat source equipment. Contact your Daikin dealer for details.
Refrigerant piping
Water piping

Features SiUS30-604
4General Information
Because the system is water cooled, the outside air temperature does not affect capacity.
Furthermore, water cooling means no defrost operation is required, so rapid starting assures
quick and comfortable heating in the coldest conditions.
Cold climate capability
General air cooled
air conditioning system
VRV-WII
Level difference
between indoor units:
up to 49 ft
Long refrigerant piping length
Within the refrigerant piping system, up to 390 ft of actual piping length and 164 ft of height
difference between the VRV-WII and indoor units are possible. Water piping does not enter
occupied spaces, so there is no worry of water leaking.
If the VRV-WII is above indoor units. 131 ft if the VRV-WII is below indoor units.
Total heating
capacity(%)
Outside air
temperature
(CDB)
-14.7
100
60
80
-12.6 -10.5 -9.5 -8.5 -7.0 -5.0 -3.0 0.0 3.0 5.0
Refrigerant piping
Water piping
VRV-WII
VRV-WII
Level difference
between
the VRV-WII units:
up to 6.5 ft
Level difference between
the VRV-WII and indoor units:
Up to 164 ft if the VRV-WII is above
Up to 130 ft if the VRV-WII is below
REFNET Joint
Actual piping length
after piping branch: up to 130 ft
Standard system (Heat pump type)
*Example only.
• Actual length up to outside unit
branch piping: up to 33 ft
• Equivalent length up to outside
unit branch piping: up to 43 ft
• Actual piping length between the VRV-WII and
indoor units: up to 390 ft
• Equivalent piping length between the VRV-WII
and indoor units: up to 459 ft
• Total piping length between the VRV-WII and
indoor units: up to 980 ft

SiUS30-604 Features
General Information 5
1.2 Easy installation
Compact and lightweight
30-3/4 inch 21-11/16 inch
0.15 ton
Stacked configuration is possible.
3200 mm
or higher
10.5 ft
or higher
(Ceiling height)
(Floor level)
(0.3–1.0 ft)
Approx. 6.6 ft
Approx.
3.3 ft
* For illustration purposes only.
IN
OUT
Adoption of a new water heat exchanger and optimization of the refrigerant control circuit has
resulted in the Industry’s most compact and lightweight equipment. A weight of 0.15 ton and
height of 39-3/8 inch make installation possible in buildings with limited space, or where no
space is available for outside units. This makes the system ideal for places that have no area
outside—such as underground malls. Stacked configuration is also possible, further
contributing to space savings.
*Unit is designed for indoor installation only.
40 HP systems28 ton systems
39-3/8 inch

Features SiUS30-604
6General Information
1.3 Energy saving
Heat recovery
In mainly cooling, partly heating mode, the system recycles
heat exhausted from the cooling operation to use for heating.
In mainly heating, partly cooling mode, the system uses cooled
post-heating operation refrigerant for cooling. Efficiency
improves the more simultaneous operation is performed.
Notes: •Operation modes (A) and (E) are applicable when the outside temperature is 95˚F and 32˚F respectively; The other modes are applicable under typical outside conditions.
• Above system configurations are for illustration purposes only.
Heat rejected
to loop
Heat rejected
to loop
Simultaneous heating and cooling operation
within the refrigerant system.
Heat recovery operation is also available between
systems connected to the same water loop, with systems
exchanging heat via water. This increases energy
efficiency.
Heat recovery operation between
the VRV-WII units.
Cooling tower (Closed type), boiler
coolingcoolingcooling
coolingcoolingcooling
The first stage: Between indoor units The second stage: Between VRV-WII units
Heat absorption
from loop
Heat absorption
from loop
A
B
C
D
E
Heat radiation operation
(all cooling operation)
Heat radiation tendency
heat recovery operation
(mainly cooling,
part heating operation)
Heat recovery operation
(cooling and heating operation)
Heat absorption tendency
heat recovery operation
(mainly heating,
part cooling operation)
Heat absorption operation
(all heating operation)
Heat rejected
to loop
Heat absorption
Heat
rejected
cooling coolingcoolingcooling
cooling heatingcoolingcooling
heating heatingcoolingcooling
heating heatingheatingcooling
heating heatingheatingheating
heatingheatingheating
heatingheatingheating
Daikin now offers 2-stage heat recovery operation.
The first stage of heat recovery operation is within the refrigerant system. By controlling the BS unit
that switches cooling and heating, simultaneous cooling and heating operation is made possible,
with heat recovery performed between indoor units.
The second stage of heat recovery operation is within the
water loop, where heat recovery is performed between
the VRV-WII units.
This 2-stage heat recovery operation substantially
improves energy efficiency and makes the system the
ideal solution to the requirements of modern office
buildings, where some areas may require cooling even in
winter, depending on the amount of sunshine received
and the number of people in the room.
Stage 1 Stage 2
VRV-WII
VRV-WII
VRV-WII
VRV-WII
VRV-WII
VRV-WII
VRV-WII
VRV-WII
VRV-WII
Heat transfer

SiUS30-604 Features
General Information 7
1.4 Enhanced usability
Centralized interlocking input is
possible using an external control
adaptor (DTA104A62).
• Features a pump interlock function that
controls the pump of the heat source
simultaneously with the starting of the
VRV-WII unit. This significantly
simplifies operation and management.
• Employs DIII-NET to enable the shared
use of the wiring between the indoor
units, the VRV-WII unit and the central
control wiring.
• Provides an auto address setting
function and check function that detects
connection errors in wiring and piping
for easier installation.
• Water piping goes only to the VRV-WII
unit, with refrigerant piping run in
occupied spaces, making the system
ideal for installing in spaces such as OA
rooms, with no worry of water leakage
or corrosion.
A variety of functions that realize easy installation
and improve reliability
DTA104A62
Interlocking
Control wiring
(external-to-external
transmission wiring)
By using one external control
adaptor circuit board,
centralized interlocking input
to multiple units within the
same water system is possible.
Easily responds to simultaneous heating
and cooling needs.
By adding suction gas piping and a BS unit (sold
separately), simultaneous heating and cooling
operation can be provided by a single system.
Standard system
(heating and cooling switching operation)
Simultaneous heating
and cooling operation system
VRV-WII unit
VRV-WII unit
Exhaust gas piping
Suction gas piping
Liquid piping
Exhaust gas piping
Liquid piping
Indoor unit Indoor unitIndoor unit
By adding suction gas piping and a BS unit...
Indoor unit
(Heating)
Indoor unit
(Cooling)
Indoor unit
(Cooling only)
Energy saving heat recovery operation!
BS unit BS unit
BS unit
Centralized interlocking function