Lennox VOSB Series User manual

1
INSTALLATION
INSTRUCTION
VRF SYSTEMS -- Indoor Units
507896-02
06/2019
THIS MANUAL MUST BE LEFT WITH THE OWNER
FOR FUTURE REFERENCE
Shipping and Packing List
General
The VOSB outside air ducted indoor units are matched
with an outdoor heat recovery or heat pump unit to
create a VRF (variable refrigerant ow) system that uses
R-410A refrigerant. VOSB indoor units are designed for
indoor installation only.
Refer to the Product Specication bulletin (EHB) for
the proper use of these indoor units with specic heat
pumps, heat recovery units, mode switching devices,
branch pipes, line sets and controls.
VOSB Outside Air Ducted Units
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Check the components for shipping damage. If you nd
any damage, immediately contact the last carrier.
Package 1 of 1 contains the following:
1 - Assembled high-static, concealed duct unit
1 - Digital Display Panel
2 - Refrigerant piping insulation sleeves
1 - Flexible condensate connector (VOSB036-054)
1 - Hose clamp (VOSB036-054)
1 - Condensate connection pipe (VOSB072-096)
(Packed in Supply side of cabinet.)
1 - Roll tape for condensate pipe (VOSB072-096)
1 - Condensate overow connection harness
1 - 120 Ohm End of Line Resistor
1 - Installation manual
WARNING
Improper installation, adjustment, alteration, ser-
vice or maintenance can cause property damage,
personal injury or loss of life.
Installation and service must be performed by a li-
censed professional HVAC installer, service agency
or the gas supplier.
Failure to follow safety warnings and these instruc-
tions exactly could result in property damage, dan-
gerous operation, serious injury, or death.
Any additions, changes, or conversions required in
order for the appliance to satisfactorily meet the ap-
plication needs must be made by a licensed profes-
sional HVAC installer (or equivalent) using factory-
specied parts.
Do not use this system if any part has been under
water. A ood-damaged appliance is extremely dan-
gerous. Immediately call a licensed professional
HVAC service technician (or equivalent) to inspect
the system and to replace all controls and electrical
parts that have been wet, or to replace the system, if
deemed necessary.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
To ensure proper system performance and reliability,
Lennox does not recommend operation of VRF sys-
tems during any phase of construction. Construction
debris, low temperatures, harmful vapors, and opera-
tion of the unit with misplaced lters can damage the
units. Failure to follow these guidelines will result in the
warranty being voided.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting
of refrigerant (CFC’s and HCFC’s) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for non-compliance.
©2019 Lennox Industries Inc. Dallas, Texas, USA
VRF

2
Model Number Identication
Safety Requirements
ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD.
Do not touch the unit or the controller if your hands are wet.
DO NOT spray water on the indoor unit for any reason.
Do not replace a fuse with a fuse of a di󰀨erent rating. Do not use a jumper wire to replace a fuse. Do not insert
your hands, tools or any other item into the air intake or air outlet at either the indoor or outdoor unit.
Do not allow children to operate the system.
WARNING
!
V OS B 036 H4 - 3 P
Brand/Family
V = Variable Refrigerant Flow (VRF)
Unit Type
OS = Outside Air Ducted Indoor Models
Major Design Sequence
B = 2nd Generation
Cooling E󰀩ciency
H = High E󰀩ciency
Refrigerant Type
4 = R-410A
Controls Protocol
3 = Phase 3
Voltage
P = 208/230V-1 phase-60hz
Nominal Cooling Capacity - Btuh
036 = 36,000 Btuh
048 = 48,000 Btuh
054 = 54,000 Btuh
072 = 72,000 Btuh
096 = 96,000 Btuh
CAUTION
VRF system piping is customized for each installation.
The LVSS piping report is an engineered design that
must be followed. The piping diagram or diagrams
included within the LVSS report have been prepared
based on the information provided to the Lennox VRF
applications department.
When the indicated lengths change from the gures
stated within the report, it is imperative that prior to the
commencement of the refrigerant pipe work installation,
Lennox VRF applications department are informed of
these proposed changes.
Upon receipt of this new information the Lennox VRF
applications department will conrm any changes that
may be applicable to this installation. If changes are
required, a new piping diagram will be produced and will
supersede all other previously provided documents.
Failure to provide this information regarding changes
to the original design may lead to insu󰀩cient capacity,
equipment failure, warranty being made void and the
refusal to commission the system.
NOTICE
When using as part of a VRF Heat Recovery system,
refer to the specic pipe connection details located in
the Mode Selection Box installation manual and the
detailed drawing on page 16 of this manual.
System Piping
NOTE - Only Lennox VRF indoor units will work with Lennox VRF outdoor units and associated mechanical
equipment. Lennox Mini Split indoor units are similar in appearance but must not be connected to a Lennox VRF
refrigerant circuit. Please refer to model numbers to conrm compatibility. Model numbers for Lennox VRF units
start with a “V” and model numbers for Lennox Mini-Splits start with a “M”.

3
Unit Dimensions - Inches (mm)
TOP VIEW
SECTION A-A
BRACKETS FOR
SUSPENDING (4)
AUXILIARY
DRAIN
CONNECTION
(Either Side)
SECTION C-C
SECTION B-B
SECTION D-D
PRIMARY
DRAIN
CONNECTION
(Either Side)
AIR FLOW
3-5/8 (92)
45-1/4 (1149)
29-1/8
(740) 25-1/8
(638) 15-5/8
(397) GAS PIPE
LIQUID PIPE
ELECTRICAL
CONTROL
BOX
7-1/4
(184)
5-3/8
(137)
5-3/8
(137)
36-5/8 (930)
(Supply Air Duct Opening)
9-3/4
(248) 16-1/2
(419)
47-1/2 (1207)
51-1/4 (1302)
LEFT SIDE VIEW
SECTION D-D
AIR FLOW
RETURN
AIR DUCT
OPENING
SUPPLY
AIR DUCT
OPENING
RIGHT SIDE VIEW
LIQUID PIPE
GAS PIPE
AIR FLOW
SECTION B-B
SUPPLY
AIR DUCT
OPENING
AUXILIARY
DRAIN
CONNECTION
(Either Side)
PRIMARY
DRAIN
CONNECTION
(Either Side)
RETURN
AIR DUCT
OPENING
SECTION C-C
SUPPLY AIR SIDE
TOP OF UNIT
RETURN AIR VIEW
SECTION A-A
TOP OF UNIT
2-1/2 (64)
(Bottom of Unit)
(Bottom of Unit)
29-1/8 (740)
23-7/8 (606)
7-1/2
(191) 4-7/8
(124)
1 (25)
1-5/8 (41)
(Supply Air
Duct Opening)
PRIMARY
DRAIN
CONNECTION
(Either Side)
AUXILIARY
DRAIN
CONNECTION
(Either Side)
42-1/4 (1073)
(Return Air Duct Opening)
13-3/8 (340)
(Return Air
Duct
Opening)
RETURN AIR
DUCT OPENING
FACTORY-
MOUNTED
LIFT PUMP
VOSB036, 048, 054

4
Unit Dimensions - Inches (mm)
TOP VIEW
SECTION A-A
BRACKETS FOR
SUSPENDING (4)
SECTION C-C
SECTION B-B
SECTION D-D
DRAIN
CONNECTION
AIR FLOW
LIQUID
PIPE
GAS
PIPE
ELECTRICAL
CONTROL
BOX
RIGHT SIDE VIEW
GAS PIPE
LIQUID PIPE
AIR FLOW
SECTION B-B
SUPPLY
AIR DUCT
OPENING
RETURN
AIR DUCT
OPENING
6
(152) 36-7/8 (937)
(Supply Air Duct Opening)
2 (51)
14-7/8
(378)
38-1/4
(972) 34-5/8
(879)
19-7/8
(505)
2-3/4
(70)
3
(76)
44-1/8(1120)
13-1/2
(343)
38-1/4 (972)
32-7/8 (835)
56-3/4 (1441)
50 (1270)
12-1/8
(308)
5-1/2
(140)
LEFT SIDE VIEW
SECTION D-D
AIR FLOW
RETURN
AIR DUCT
OPENING
SUPPLY
AIR DUCT
OPENING
20-7/8
(530)
RETURN AIR VIEW
SECTION A-A
TOP OF UNIT
(Bottom of Unit)
(Supply Air
Duct Opening)
RETURN AIR
DUCT OPENING
SECTION C-C
SUPPLY AIR SIDE
TOP OF UNIT
(Bottom of Unit)
VOSB072, 096

5
Clearances
Refer to Figure 1 for minimum clearance requirements.
20” (508 mm) Minimum Service Clearance
24” (610 mm)
Air
Flow
24” (610 mm)
Minimum
Service
Clearance
TOP VIEW
DUCTED
UNIT
FRONT VIEW
24” (610 mm) Minimum Clearance
Ceiling
Wall
Wall
1” (25 mm) Minimum Clearance
CeilingSuspended
Minimum
Service
Clearance
Figure 1. Minimum Installation Clearances
NOTE - No part of the suspended ceiling, or other supports not directly associated with the indoor unit installation,
can be xed to, or touch the indoor unit, in any form. Minimum clearances must be observed at all times.
NOTE - Horizontal installation only.

6
Unit Placement
AVOID
Do not install the unit in the following locations:
• Areas near commercial kitchen exhaust hoods where
odors and grease may enter the air stream.
• Areas near ue and/or exhaust vents where ue
gasses, waste gasses, or debris may enter the air
stream.
• Areas exposed to petrochemicals or petrochemical
products
• Areas exposed to salt or other corrosive materials or
caustic gasses
• Areas exposed to extreme voltage variations (such as
factories
• Tightly enclosed areas that may impede service of the
unit
• Areas exposed to fossil fuels (such as oil or gas in
kitchens)
• Areas exposed to strong electromagnetic forces
• Areas exposed to acids or alkaline detergents (laundry
rooms)
DO:
• Locate the unit so that it is not exposed to direct
sunlight
• Ensure the structural ceiling can support the weight
of the unit.
• Select a location where condensate line will have the
shortest run to a suitable drain per local codes.
• Allow su󰀩cient space around unit for proper operation
and maintenance
• Install unit a minimum of 3 feet away from any antenna,
power cord (line) radio, telephone, security system, or
intercom. Electrical interference and radio frequencies
from any of these sources may a󰀨ect operation
WARNING
Do not install the unit in an area where ammable
materials are present due to risk of explosion resulting
in serious injury or death.
Check suitability of structure to which the unit support
mechanism will be xed to. If structure is not capable
of carrying the weight of the unit, unit may fall causing
personal injury or equipment damage.
Use the provided and specied components when
installing equipment. Failure to do so may result in
unit falling, water leaking or electrical shocks, causing
personal injury or equipment or property damage.
Consider the possibility of earthquakes in your area
when installing the equipment. If the unit is not correctly
secured, it may fall, causing personal injury or equipment
damage.
Safely dispose of packing materials, which include
nails, wood and other sharp objects, as well as plastic
wrapping. Children playing with plastic wrap or bags risk
the danger of su󰀨ocation.
CAUTION
Do not place items which may be damaged by water
under or around the unit.
The unit should be installed at least 8 feet above the
oor (if possible) to ensure maximum performance and
comfort.

7
Installation
It is important to locate the unit where it can be accessed
for service in the future. Refer to unit dimensions on Pages
3-5 for exact locations of suspension brackets, return air
and supply air openings.
1. Make sure that the structural ceiling or slab is able
to support the weight of the indoor unit. It may be
necessary to add extra support.
2. Install suspension rods in the structural
ceiling or concrete slab in a suitable location.
If the structural ceiling is constructed of concrete,
install anchors to accept four ⅜” threaded rods to
suspend the indoor unit. If the structural ceiling
includes wooden joists, use angle iron or Unistrut
channel xed securely in place to accept the ⅜”
threaded rods. NOTE - Threaded rod (requirement
of Lennox warranty program) is the ONLY acceptable
method of suspending the unit; do not use chains or
straps. See Figure 2.
3. Slide one nut and one washer onto each threaded rod.
Use electrical tape to keep the washer from failing o󰀨.
Position the nuts slightly above the nal resting place
of the four suspension brackets. See Figure 3.
Figure 2. Suspending Methods
ANGLE IRON
BOLTED IN
PLACE ACROSS
WOODEN JOISTS
WOODEN JOIST
⅜” THREADED
ROD
ANGLE IRON
ACROSS
WOODEN JOISTS
ANCHOR
CONCRETE CEILING
USING ANCHORS
⅜” THREADED
ROD
4. Use either a mechanical lifting device or a minimum of
two people to raise the unit and insert the threaded rods
into the suspension brackets on the unit base. Slide
a washer and then a nut onto each rod below each
suspension bracket. Use the leveling nut (beneath
suspension bracket) to adjust the unit to the correct
height. Remove the electrical tape holding the upper
washers and nuts in place and tighten each of the four
nuts above the brackets down onto the brackets. This
will ensure that the unit remains level.
5. It is recommended to install a eld-provided isolation
grommet as shown in Figure 4 to prevent transmission
of vibration from unit to structural ceiling.
6. If the unit is being installed in an application that includes
a sheet rock (plasterboard) ceiling, it is required that
an access panel be installed in a suitable location.
This will also allow access for future maintenance
(requirement of Lennox warranty program).
Access is required during the commissioning process
to test the condensate disposal system and to check
the local disconnect.
7. The unit is factory-congured for the supply air to be
delivered from the front and the return air lter at the
rear of the unit.
INSTALLATION GUIDELINES
• It is recommended to install a eld-provided isolation
grommet as shown in Figure 4 to prevent transmission
of vibration from unit to structural ceiling.
• Provide separate support for the weight of the duct
system. Duct system must not be supported by the
indoor unit.
• Use exible joints (canvas) at the point where the duct
connects to the unit on both ends. Material must meet
all local and national code requirements.
• When unit is being installed in a location where even
the slightest noise would be a problem (meeting room
or other very quiet space), design duct system to avoid
transmission of vibration to the structure to the extent
possible.
• When sizing the return air lter grille, a minimum
surface area of 200 sq. in. per ton is recommended.
LEVELING
NUT
⅜”THREADED
ROD
SUSPENSION
BRACKET
FIELD-PROVIDED
ISOLATION GROMMET
WASHER
INDOOR UNIT
LEVELING
NUT
⅜”THREADED
ROD
SUSPENSION
BRACKET
SUPPLY AIR
OPENING
FRONT VIEW
When unit is
level, tighten
nut to secure
position of
suspension
bracket on
rod.
Figure 3. Suspension Hardware
Figure 4. Isolation Grommet

8
Return Air Filter
Return Air Filter
The factory-supplied return air lter is segmented to allow
it to be separated if needed to remove it from the unit in
tight spaces. The segments are connected with hook &
loop (Velcro-style) straps. See Table 1 for lter dimen-
sions.
Figure 5. Segmented Factory-Supplied
Return Air Filter
Remove Return Air Filter Instructions
1. Loosen the screw that secures the lter retaining
bracket and slide the bracket away from the unit.
2. Grasp the lter removal tab and slide the lter out.
Figure 6. Loosen Filter Retaining Bracket
Filter
removal
tab
Figure 7. Slide Out Filter
Filter removal tab
3. Reverse these steps to reinstall the lter. Be sure
to reinstall the receiver if it was detached during the
lter removal.
Figure 8. Filter Partially Removed
Indoor Unit Model Filter Dimensions Each Section of Filter Dimensions
VOSB036, 048, 054 42-5/8 x 13-1/4 x 3/8 in.
1083 x 336 x 10 mm
14-1/8 x 13-1/4 x 3/8 in.
359 x 336 x 10 mm
VOSB072, 096 44-1/2 x 13-1/4 x 3/8 in.
1130 x 336 x 10 mm
14-3/4 x 13-1/4 x 3/8 in.
375 x 336 x 10 mm
Table 1. Filter Dimensions
Hook & Loop Strap
External Static Pressure setting on wired controller
• Use high speed air ow for selection and design.
• Set the external static pressure (ESP) on wired
controller, the setting value should not be 0.2 in.w.g
(50Pa) higher than the actual external static pressure
of the duct.
External Static Pressure

9
Refrigerant Piping Connections
IMPORTANT
The compressor in the unit this air handler is matched
with contains PVE oil (Polyvinyl ether). PVE oil is
formulated for hydrouorocarbon (HFC) refrigerants,
such as R410A, which this system contains. While it may
have some miscibility properties with mineral-based oil
and POE oil (Polyolester), it is not recommended to mix
PVE oil with any other type of refrigerant oil.
Refrigerant leaks are unlikely; however, if a refrigerant
leak occurs, open a door or windows to dilute the
refrigerant in the room. Turn o󰀨 the unit and all other
appliances that may cause a spark. Call a licensed
professional HVAC technician (or equivalent) to repair
the leak.
Use only R410A refrigerant to charge this system. Use
of other refrigerant or gas will damage the equipment.
Do not allow air or other contaminants to enter system
during installation of refrigerant piping. Contaminants
will result in lower system capacity and abnormally high
operating pressures and may result in system failure or
explosion.
Insulate all refrigerant piping.
Refrigerant pipes may be very hot during unit operation.
Do not allow contact between wiring and bare copper
pipes.
After refrigerant piping connections have been
completed, check the system for leaks per
commissioning instructions.
WARNING
WARNING
Danger of re. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing torch
to a pressurized system may result in ignition
of the refrigerant and oil mixture. Check the
high and low pressures before applying heat.
CAUTION
Brazing alloys and ux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing operations.
Perform operations only in well-ventilated areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and ux.
IMPORTANT
Refrigerant lines must be clean, dry, refrigerant-grade
copper lines. Air handler coils should be installed
only with specied line sizes for approved system
combinations.
Handle refrigerant lines gently during the installation
process. Sharp bends or kinks in the lines will cause
restrictions.
IMPORTANT
Only use brazing rods/sticks which are suitable/
recommended for air conditioning pipework installations
- Do Not Use Soft Solder.
CAUTION
Purge low pressure nitrogen [1 to 2 psig (6.0 to 12.8
kPA)] through the refrigerant piping during brazing. This
will help to prevent oxidation and the introduction of
moisture into a system.
To prevent the build-up of high levels of nitrogen when
purging be sure it is done in a well ventilated area.

10
Table 2. Refrigerant Piping Connections
• Refrigerant lines must be connected by a qualied
technician in accordance with established procedures.
• Field provided piping consists of two HVAC/R rated
copper lines connected to the indoor unit.
• Final equipment connections must be brazed
connections. Compression or other types of ttings
are not permitted for nal connections.
• All refrigerant piping shall be free of defects, debris,
and oil.
• Copper-phosphorous brazing alloys are to be used to
join all pipework connections where applicable.
• Always ow/purge nitrogen to avoid oxidation while
brazing.
• Always use an appropriate heat absorption compound
to protect the unit and internal sensors from conductive
heat while brazing.
1. The seal on the unit refrigerant piping connections
should remain in place until the last possible moment.
This will prevent dust or moisture from getting into the
refrigerant piping before it is connected.
2. Prior to brazing remove rubber air grommets from
indoor unit refrigerant line ports.
3. Slowly loosen one of the rubber plugs to release the
factory nitrogen charge. Remove the rubber plug from
both liquid and gas lines.
4. Connect the liquid and gas lines to the evaporator coil.
5. Reinstall the rubber grommets into the refrigerant
piping panel.
6. Insulate both pipes individually.
Sealing the Unit
Seal the unit so that warm air is not allowed into the
cabinet. Warm air introduces moisture, which results in
condensation problems.
This is especially important when the unit is installed in an
unconditioned area.
If installed in an unconditioned space, sealant should be
applied around the electrical wires, refrigerant tubing, and
condensate lines where they enter the cabinet.
WARNING
There must be an air-tight seal between the unit and the
return air plenum. Use berglass sealing strips, caulking,
or equivalent sealing method between the plenum and
the air handler cabinet to ensure a tight seal. Return
air must not be drawn from a room where this unit or
any gas-fueled appliance (i.e. water heater) or carbon
monoxide-producing device (i.e. wood replace) is
installed.
Indoor Unit Size
(Btuh) Liquid Line Vapor Line
36,000
48,000
54,000
3/8” 5/8”
72,000
96,000 3/8” 7/8”

11
Condensate Piping Connections
1. Use the provided hose clamp to secure the
provided exible condensate drain connector
and insulating sleeve to the drain line stub
on the side of the indoor unit. See Figure 9.
NOTE - Take care not to over-tighten the hose clamps
this may damage the drain line stub.
2. Make a water-tight connection between the eld-
provided condensate drain line and the exible
condensate connector (1” I.D.).
INSULATION
INDOOR
UNIT
CONDENSATE
LINE STUB
HOSE CLAMP
FLEXIBLE DRAIN
CONNECTOR PVC DRAIN
PIPE
1” I.D.
1” O.D.
(BOTTOM OF UNIT)
036 SHOWN
AIR FLOW
SUPPLY
AIR DUCT
OPENING
AUXILIARY
DRAIN
CONNECTION
(EITHER SIDE VOSB036-054)
RETURN
AIR DUCT
OPENING
PRIMARY
DRAIN
CONNECTION
(EITHER SIDE VOSB036-054)
(ONE SIDE VOSB072--96)
Figure 9. Condensate Drain Connection
3. See Figure 10 for applications including a single unit
and a single gravity drain. In this case, ensure that
the drain line is properly sloped (no less than 1/4 inch
per foot) and condensate lines are routed to ensure
moisture is drained away from the indoor unit.
Suspension Rods
Drain line
Structural Ceiling
3 ft.
(1 m)
Support
straps
NOTE - Drain line should be sloped 1/4 inch per foot (18 mm per m)
AWAY from unit and should be supported as needed to prevent sagging.
Do not overtighten drain fitting.
Do not operate unit without condensate drain trap.
Clean Out
Do not glue
3”
3”
Anti-siphon vent must extend above the
height of the coil drain pan by 2” (51 mm).
1 ft.
(305 mm) max
Indoor Unit
Figure 10. Sloped Condensate Gravity Drain
Single Unit
CAUTION
Make sure that drain piping is properly routed and
insulated in order to prevent both leaks and condensation.
Follow these instructions exactly to ensure proper
drainage and unit operation.
IMPORTANT
You must conrm operation of every drain and pump in
the system as part of the commissioning procedure.
IMPORTANT
Drain should have a slope of at least 1/4 inch per foot
and should be approved corrosion-resistant pipe.
4. See Figure 12 for applications including multiple units
and a single gravity drain. In this case, ensure that
the drain line is properly sloped (no less than 1/4 inch
per foot) and condensate lines are routed to ensure
moisture is drained away from the indoor unit. See
5. See Figure 11 for applications including a single unit
using the factory-mounted lift pump.
VOSB036-054 indoor units have a factory-installed
condensate lift pump capable of 28 inches (711 mm) of lift
and one gravity drain connection on each side of the unit.
If using gravity drain, select one connection to use and
leave the unused connection port sealed.
Seal and plug the lift pump connection port
when using a gravity drain connection port.
Disconnect the factory-installed lift pump that is connected
to the CN labeled PUMP..
VOSB072-096 indoor units have one gravity drain
connection.
SUSPENSION RODS
DRAIN LINE
STRUCTURAL CEILING
8 in.
(203 mm)
Max. 18 in.
SUPPORT
STRAPS
3 ft. (1 m)
Figure 11. Condensate Drain with Lift Pump
Single Unit
6. See Figure 13 for applications including multiple units
using the internal lift pump to provide lift into a single,
correctly sized main drain. In this case, ensure that
the main drain line is properly sloped, no less than
1/4 inch per foot (6 mm per 305 mm), and that each
individual drain is connected to the main drain exactly
as shown.

12
Figure 12. Sloped Condensate Gravity Drain
Multiple Indoor Units
Table 3. Condensate Pump Accessory Options
Capacity Brand Model Name Model # Cat #
Max Flow
Rate
(gal per hr)
Max
head
Max
suction
lift*
VOSB072-096
Lennox VRF Drain Pump Kit V8DRNP05 17U32 - 18 in -
Blue
Diamond MegaBlue X87-835 14T71 13.2 66.5 ft 23 ft
*Optional pump maximum suction lift is measured from the pump outlet.
Indoor Unit
2~3-15/16 in.
8 in.
2~3-15/16 in.
2~3-15/16 in.
MAIN DRAIN
INDIVIDUAL DRAIN OUTLET FROM EACH INDOOR UNIT
(Must be connected to internal pump and must be routed to
main drain as shown.)
tinUroodnItinUroodnI
(Sloped at1/4” per foot (6 mm per 305 mm) AWAY
from unit and should be supported as needed to prevent sagging.)
8 in. 8 in.
Max. 18 in.
Max. 18 in.
Max. 18 in.
Indoor Unit tinUroodnItinUroodnI
Install a trap for each indoor unit.
3”
3”
Clean Out
3”
3”
3”
3”
Suspension
Rods
3 ft.
(1 m)
Support
straps
NOTE - Drain line should be sloped 1/4 inch per foot (18 mm per m)
AWAY from unit and should be supported as needed to prevent sagging.
Do not overtighten drain fitting.
Do not operate unit without condensate drain trap.
Install an anti-siphon vent for each trap - must extend above
the height of the coil drain pan by 2” (51 mm).
1 ft.
(305 mm) max
Vent
Vent
Clean Out
Clean Out
Figure 13. Condensate Drain with Lift Pump
Multiple Indoor Units
7. In all cases, drain should be as short as possible and
should not have any droops or kinks that would restrict
condensate ow and shall be constructed using an
approved pipe. All drains should contain traps. There
must be a 2-inch space between the end of the
condensate drain and the nal termination point
(ground, open drain, etc.) to ensure that the line
will drain freely.
8. After system installation is complete, the
condensate drain line must be checked for leaks
and if a condensate pump has been tted, it must
be checked to ensure proper operation. This
check is part of the commissioning procedure.

13
Model
Condensate
Life Pump
Factory
Mounted
Condensate
Pump Lift
Measurement
Condensate Pump
Facility on Indoor
PCB Board
Condensate
Outlet of
Indoor Unit
Flexible Drain Con-
nection (supplied
with unit)
VOSB Outside Air
Ducted
Yes - 036-054
No - 072/096 18 “ Yes
1” O.D.
1-5/8” O.D.
adapter pro-
vided
1” I.D.
Table 4. Condensate Connection Sizes
Wiring Connections
In the U.S.A., wiring must conform with current local
codes and the current National Electric Code (NEC). In
Canada, wiring must conform with current local codes and
the current Canadian Electrical Code (CEC).
Refer to unit nameplate for minimum circuit ampacity and
maximum overcurrent protection size.
NOTE - Two-conductor stranded shielded cable must be
used for the communication wiring. This is necessary to
ensure proper system communication and operation.
• Indoor and outdoor unit equipment must each be on
their own a dedicated breaker.
• Indoor units must have a dedicated service disconnect.
Switches are acceptable; however it must be a double
pole switch that disconnects L1 and L2.
WARNING
Isolate the power supply before accessing unit electrical
terminals.
Install unit so that unit disconnect is accessible.
Follow all local and national codes, as well as this
installation instruction, during installation. Do NOT
overload electrical circuit, as this may lead to failure and
possible re.
Use specied wiring and cable to make electrical
connections. Clamp cables securely and make sure that
connections are tight to avoid strain on wiring. Insecure
wiring connections may result in equipment failure and
risk of re.
Wiring must be installed so that all cover plates can be
securely closed.
Do not attempt to repair a damaged power cord.
Do not modify the power cord in any way. Do not
attempt to extend the length of the power cord or use
an extension cord with this appliance. Do not share the
single power outlet with any other appliances.
CAUTION
This unit must be properly grounded and protected by a
circuit breaker. The ground wire for the unit must not be
connected to a gas or water pipe, a lightning conductor
or a telephone ground wire.
Do not connect power wires to the outdoor unit until
all other wiring and piping connections have been
completed.
Install all wiring at least 3 feet away from televisions,
radios or other electronic devices in order to avoid the
possibility of interference with the unit operation.
Do not install the unit near a lighting appliance that
includes a ballast. The ballast may a󰀨ect remote control
operation.
Using an External Water Level Switch
1. Disconnect the closed circuit loop connection
labeled WATER.
2. Connect the provided overow harness accessory to
the WATER connection. See Figure 14.
3. See unit wiring diagrams for location of the WATER
connection.
The connection has 5 VDC current, do not supply eld
voltage.
Table 3 lists available external condensate pump
accessories. See Table 4 for connection sizes.
G
L2
L1
NC
COM
NO
PUMP
CONNECTIONS
0.5A
G
L1
L2
GREEN
OPTIMAL
Cut wire here
INDOOR
UNIT
MAIN
BOARD
Connect to
pump here
using solder
or butt joints
WATER
WATER
Figure 14. External Water Level Switch Connection

14
1. Remove the screws that secure the control box cover.
Remove the cover and place it to the side where it will
not be damaged.
2. Locate the terminal strip in the control box. Connect
the power wiring (sized per NEC/CEC and local codes)
and communications cable (two-conductor shielded
cable). Refer to unit nameplate for rated voltage.
3. If the indoor unit is the nal unit in a group that is wired
in series, install the provided resistor across terminals
P and Q.
Figure 15. Typical Power Wiring Diagram (VRF Heat Recovery System Shown)
L2 L3L1
L2L1
208/230V 3Ph 60Hz
or 460V 3Ph 60Hz
Power supply
208/230V 1Ph 60Hz
Power supply
Mode Selection Box Indoor unit Indoor unit Indoor unit
Dedicated
breaker
Service
Disconnect
L1 L2
L1 L2
Fuse
Service
Disconnect
L1 L2
Fuse
Service
Disconnect
L1 L2
Fuse
Service
Disconnect
L1 L2
Fuse
Outdoor Unit (Main Unit)
L1 L2 L3
Outdoor Unit (Sub1 unit)
L1 L2 L3
Outdoor Unit(Sub2 Unit)
L1 L2 L3
L1 L2 L3
L1 L2 L3
L1 L2 L3
L1 L2 L3
L1 L2 L3
L1 L2 L3
Service
Disconnect
Service
Disconnect Service
Disconnect
Indoor units and mode selection boxes on the same
refrigeration circuit should have a common power
supply but must have an independent disconnect switch
installed adjacent to each item of equipment for servicing
and maintenance purposes. Indoor unit and mode
selection box power supply MUST not be taken from the
outdoor unit. Always follow NEC/CEC and Local Codes.

15
Figure 16. Typical Communication Wiring Diagram (VRF Heat Recovery System)
NOTE - Each communication wire from the MS box should follow the refrigerant piping for that port.
P Q
All Drain Wires will connect from outdoor unit chassis to mode selection box chassis at the end of
the signal run.
18 GA., stranded, 2-conductor, shielded control wire (polarity sensitive).
Typical Wiring Diagram, NEC/CEC and Local Codes apply.
Outdoor unit Outdoor unit
(sub1 unit)
Outdoor unit
(sub2 unit)
(PQ)
(main unit)
(PQ)
MS
Box
(PQ)
(PQ)
MS
Box
(PQ)
(PQ)
(H1 H2 ) (H1 H2 ) (H1 H2 )
Outdoor Unit Communication Terminal Block
P Q H1 H2X YO AK1 K2
MS Box Communication
Terminal Block
P Q
Indoor Unit Communication Terminal Block
HA HB 12V COM P Q
Ground drain wire or
cable shield
to MS Box
and Outdoor Unit chassis
Install a terminating resistor (Ω120) on terminals P&Q on the indoor unit
which is furthest from the outdoor unit.

16
Figure 17. Typical Communication Wiring Diagram (VRF Heat Pump System)
(PQ)
(PQ)
Outdoor unit
(mainunit)
Outdoor unit
(sub1unit)
Outdoor unit
(sub2 unit)
Install a terminating resistor (Ω120) at the last indoor unit terminals P and Q of the daisy chain.
P Q
All shields of shielded cable connect to chassis GROUND terminal at Indoor Units.
18 GA., stranded, 2-conductor,shielded control wire (polaritysensitive).
Typical Wiring Diagram, NEC/CEC and Local Codes apply.
(H1 H2 )
Outdoor Unit Communication Terminal Block
P Q H1 H2X YO AK1 K2
(H1 H2 )
(H1 H2 )
Indoor Unit Communication Terminal Block
HA HB 12V COM P Q
Ground cable shield
to Indoor Unit chassis
Tightening torque for the terminal screws
• Use the correct screwdriver for tightening the terminal
screws.
• If the terminal screws are over tightened, screws
might be damaged.
• Refer to Table 5 for the tightening torque of the
terminal screws.
Table 5. Terminal Screw Tightening Torque
Tightening torque (lb-ft)
Terminal base of
remote controller/Signal
transmission wire (X2M)
0.58-0.72
Terminal base of power
supply (X1M) 0.87-1.06
Grounding terminal (M4) 1.06-1.43
• After wiring, conrm all connections are correct; Then
turn on power supply to the unit.
IMPORTANT
DO NOT adjust DIP switch settings. Settings may only
be adjusted by a trained technician as part of the com-
missioning procedures.

17
Figure 18. VOSB036H4-3, VOSB048H4-3, & VOSB054H4-3
Typical Wiring Diagram
Typical wiring diagram. Refer to wiring diagram on the unit for actual wiring.
T2A
Outlet of evaporator sensor
Inlet of evaporator sensor
T2B
Indoor fan motor
Inlet air temperature sensor
T0
FM
Code Title
XS1-5
XP1-5 Connectors
Connectors
Main Board
CN3 CN18
CN24
CN11 CN5 CN52 CN54 CN12
CN15
CN9
CN26
CN8
EARTH
PUMP
EEV
CS
( Current range: 0-1A)
(
Voltage range: 0-24V AC/DC
)
ON/OFF
SWITCH
CN14
ALARM
POWER IN
LACKB
DER
XT1
L1 L2
G/Y
CN2{L_IN}
CN4{N_IN}
CN6
CN20
SVD
T2
TA
DC motor
drive board
CN13
CN3
“ +5V GND +12V ”
ONLY USED
FOR TESTING
To wired
controller
comm. bus
To outdoor/
indoor/MS
units
comm.bus
YELLOW
GRAY
WHITE
BLUE
XT2
RED
BLACK
HA HB 12V COM QP
CN30
Middle of evaporator sensor
EEV
Terminals
Pump motor
Water level switch
Warning lamp
Electronic expansion valve
XT1-2
PUMP
CS
ALARM
SVD Solenoid valve
Code Title
T2B
EULB
T2A
WHITE
T1/T0
RED
ACKLB
TA
CALB K
T2
Outlet air temperature sensor
To wired
controller
power
Display Board
NOTE:
Component in dash line is optional or field wiring
Error code
Error Content
E0
E1
E2
E4
E5
Mode conflict
Communication error between indoor and main outdoor unit
T0 (Inlet air temperature sensor) malfunction
TA (Outlet air temperature sensor) malfunction
T2B (Outlet of evaporator sensor) malfunction
T2A (Inlet of evaporator sensor) malfunction
Error Content
Error code
FE
Eb
U4
Ed
EE
F8
No address
EEV malfunction
MS self-inspection error
Outdoor unit fault
High water alarm
MS error
E6
DC fan motor error
E7
EC
EEPROM failure
E3
T2 (Middle of evaporator sensor) malfunction
D8
A0
Remote off
Emergency stop
NOTE:
1. Refer to manual for
communication wiring
2. Please use the 2-conductor
shielded twisted cable for
communication
XP1
XP2
XP3
XS1
XS2
XS3
XP4
XS4
XP5
XS5
N=3
N=4
HHE interface
FAN
CTON
HTON 4 5 6
CN50
FM
FAN
CO2
sensor
Vco2
COM
78
GND
Vco2

18
Figure 19. VOSB072H4-3 and VOSB096H4-3 Typical Wiring Diagram
Main Board
CN3 CN28
CN24
CN11 CN5 CN54 CN12
CN15
CN9
CN26
CN8
EARTH
EULB
WHITE
RED
PUMP1
EEV
CS
FM
( Current range: 0-1A)
(
Voltage range: 0-24V AC/DC )
FAN
CN14
ALARM
POWER IN
LACKB
DER
XT1
L1 L2
G/Y
CN2{L_IN}
CN4{N_IN}
CN6
ACKLB
CN20
SVD
TA
DC motor
drive board
CN13
CN3
“ +5V GND +12V ”
ONLY USED
FOR TESTING
CALB K
CN30
CN57+
CN58-
CN29
RED
BLACK
BLUE BLUE
~
+
-
Rectifier Bridge
CN27
DC motor
drive board
CN13
CN3
FM
FAN
XP6XS6
To wired
controller
comm. bus
To outdoor/
indoor/MS
units
comm.bus
YELLOW
GRAY
WHITE
BLUE
XT2
RED
BLACK
HA HB 12V COM QP
To wired
controller
power
Display Board
PUMP2
CN18
NOTE:
Component in dash line is optional or field wiring
NOTE:
1. Refer to manual for communication wiring
2. Please use the 2-conductor shielded twisted
cable for communication
T2A
Outlet of evaporator sensor
Inlet of evaporator sensor
T2B
Indoor fan motor
Inlet air temperature sensor
T0
FM
Code Title
XS1-6
XP1-6 Connectors
Connectors
T2
Middle of evaporator sensor
EEV
Terminals
Pump motor
Water level switch
Warning lamp
Electronic expansion valve
XT1-2
PUMP
CS
ALARM
TA
SVD Solenoid valve
Code
Title
Outlet air temperature sensor
Error code
Error Content
E0
E1
E2
E4
E5
Mode conflict
Communication error between indoor and main outdoor unit
T0 (Inlet air temperature sensor) malfunction
TA (Outlet airtemperature sensor) malfunction
T2B (Outlet of evaporator sensor) malfunction
T2A (Inlet of evaporator sensor) malfunction
Error Content
Error code
FE
Eb
U4
Ed
EE
F8
No address
EEV malfunction
MS self-inspection error
Outdoor unit fault
High water alarm
MS error
E6
DC fan motor error
E7
EC
EEPROM failure
E3
T2 (Middle of evaporator sensor) malfunction
D8
A0
Remote off
Emergency stop
T2B
T2A
T1/T0
T2
XP1
XP2
XP3
XS1
XS2
XS3
XP4
XS4
XP5
XS5
~
N=3
N=3
N=4
CO2
sensor
Vco2
GND
Vco2
COM
78
ON/OFF
SWITCH
CN52
HHE interface
FAN CTON
HTON
4 5 6
CN50
Lorem ipsum
Typical wiring diagram. Refer to wiring diagram on the unit for actual wiring.
Dip-switch setting:
See Table 6 for allowed indoor to outdoor unit combinations.
Use the SW8-1 dip switch to set whether or not the all of the indoor units in the system are VOSB units or if there is a
mix of indoor units in the system.
0 - All indoor units in the system are VOSB.
1 - VOSB and common indoor units mix in one system.
Outdoor Unit Indoor Unit IDU/ODU
Connection Ratio
VOSB/ODU
Connection Ratio
Heat Pump VOSB Only ≤100% ≤100%
Heat Pump VOSB + other indoor units ≤100% ≤30%
Heat Recovery VOSB Only NOT ALLOWED NOT ALLOWED
Heat Recovery VOSB + other indoor units ≤100% ≤30%
Table 6. VOSB Indoor Unit to Outdoor Unit Allowed Connection Ratio

19
Relocate T0 Return Air Sensor
Figure 20. Identify T0 Sensor Connection on PCB
This sensor can be extended with 18 AWG stranded
shielded cable.
1. Identify the T0 connection on the main board - CN4.
(white wires soldered to PCB)
Figure 21. Identify White Plug into Black Wire
Figure 22. Cut the Black Wire
2. Identify where the white wire is plugged into the black
wire.
3. Cut the black wire between the plug and the sensor
thermistor. Leave adequate room for making wiring
connections on each end.
4. Prepare the 18 AWG stranded shielded extension
cable.
5. Solder the extension cable to the black wire on each
end or use the VRF accessory V0SNSR00P (13G99)
to splice in the extension cable.
6. Locate the return air thermistor to the conditioned
area of which the indoor unit serves.
Figure 23. Sensor Thermistor
IMPORTANT
Avoid installing sensor in high load or heat loss areas
such as exterior walls or walls that are against uncondi-
tioned spaces, near entry doors and windows, or where
direct sunlight may be present.
Relocate the unit return air from inside the unit to a loca-
tion within the conditioned zone whenever the return is
pulling air from above the ceiling or if fresh air is being
introduced and mixed into the return. The T0 sensor can-
not accurately read the space temperature under these
conditions if the sensor remains located inside of the unit.

20
T2A
Outlet of evaporator sensor
Inlet of evaporator sensor
T2B
Indoor fan motor
Inlet air temperature sensor
T0
FM
Code Title
XS1-5
XP1-5 Connectors
Connectors
Main Board
CN3 CN18
CN24
CN11 CN5 CN52 CN54 CN12
CN15
CN9
CN26
CN8
EARTH
PUMP
EEV
CS
( Current range: 0-1A)
(
Voltage range: 0-24V AC/DC
)
ON/OFF
SWITCH
CN14
ALARM
POWER IN
LACKB
DER
XT1
L1 L2
G/Y
CN2{L_IN}
CN4{N_IN}
CN6
CN20
SVD
T2
TA
DC motor
drive board
CN13
CN3
“ +5V GND +12V ”
ONLY USED
FOR TESTING
To wired
controller
comm. bus
To outdoor/
indoor/MS
units
comm.bus
YELLOW
GRAY
WHITE
BLUE
XT2
RED
BLACK
HA HB 12V COM QP
CN30
Middle of evaporator sensor
EEV
Terminals
Pump motor
Water level switch
Warning lamp
Electronic expansion valve
XT1-2
PUMP
CS
ALARM
SVD Solenoid valve
Code Title
T2B
EULB
T2A
WHITE
T1/T0
RED
ACKLB
TA
CALB K
T2
Outlet air temperature sensor
To wired
controller
power
Display Board
NOTE:
Component in dash line is optional or field wiring
Error code
Error Content
E0
E1
E2
E4
E5
Mode conflict
Communication error between indoor and main outdoor unit
T0 (Inlet air temperature sensor) malfunction
TA (Outlet air temperature sensor) malfunction
T2B (Outlet of evaporator sensor) malfunction
T2A (Inlet of evaporator sensor) malfunction
Error Content
Error code
FE
Eb
U4
Ed
EE
F8
No address
EEV malfunction
MS self-inspection error
Outdoor unit fault
High water alarm
MS error
E6
DC fan motor error
E7
EC
EEPROM failure
E3
T2 (Middle of evaporator sensor) malfunction
D8
A0
Remote off
Emergency stop
NOTE:
1. Refer to manual for
communication wiring
2. Please use the 2-conductor
shielded twisted cable for
communication
XP1
XP2
XP3
XS1
XS2
XS3
XP4
XS4
XP5
XS5
N=3
N=4
HHE interface
FAN
CTON
HTON 4 5 6
CN50
FM
FAN
CO2
sensor
Vco2
COM
78
GND
Vco2
Figure 24. Identify T0 Sensor on Wiring Diagram
Typical wiring diagram. Refer to wiring diagram on the unit for actual wiring.
Figure 25. Typical Wiring Connections
CN4
18 AWG stranded shielded cable
White plug
White wire
Black wire Black wire
Thermistor
Solder or connect with V0SNSR00P
Setting Blower Operation
Blower cycling can be congured to determine indoor
operation.
• Default operation is indoor unit blower OFF when the
indoor unit is in thermo OFF.
• Settings can be adjusted in the -3P controller and
cannot be congured at the indoor unit PCB.
• Consult the specic controller manual for detailed
blower setting information.
NOTE - Ensure the blower is set to the ON position when
using an electrical duct heater.