Lennox VRF V33B Series User manual

1
©2018 Lennox Industries Inc. Dallas, Texas, USA
INSTALLATION
INSTRUCTION
VRF SYSTEMS -- Indoor Units
507890-02
01/2019
THIS MANUAL MUST BE LEFT WITH THE OWNER
FOR FUTURE REFERENCE
Shipping and Packing List
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 indoor cassette unit base
8 - Nuts
8 - Washers
4 - Cover panel screws
5 - Wire ties
1 - Condensate drain exible pipe
1 - Condensate drain insulation sleeve
1 - Clasp
1 - Cable
2 - Refrigerant pipe insulation
2 - Brass are nuts
1 - Template
1 - Installation manual
NOTE - Assembled indoor unit cover panel is required for
complete installation and must be ordered separately.
The V33B 360º cassette indoor units are matched with an
outdoor heat recovery or heat pump unit to create a VRF
(variable refrigerant ow) system that uses HFC-410A
refrigerant. V33B 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.
These instructions are intended as a general guide and
do not supersede local or national codes in any way.
Authorities having jurisdiction should be consulted before
installation.
V33B 360º Cassette Units
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause property damage, personal
injury or loss of life.
Installation and service must be performed by a licensed
professional HVAC installer, service agency or the gas
supplier.
Failure to follow safety warnings and these instructions
exactly could result in property damage, dangerous
operation, serious injury, or death.
Any additions, changes, or conversions required in order
for the appliance to satisfactorily meet the application
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 (CFCs, HCFCs and HFCs) as of July
1, 1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarceration
may be levied for noncompliance. These units must be
installed as a part of a matched system as specied in
the Product Specications (EHB) bulletin.
General
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 33 B 012 H4 - 3 P
Brand/Family
V = Variable Refrigerant Flow (VRF)
Unit Type
33 = High E󰀩ciency 360° Cassette 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
Nominal Cooling Capacity - Btuh
009 = 8,500 Btuh
012 = 12,000 Btuh
015 = 15,000 Btuh
018 = 18,000 Btuh
024 = 24,000 Btuh
030 = 30,000 Btuh
036 = 36,000 Btuh
048 = 48,000 Btuh
Voltage
P = 208/230V-1 phase-60hz
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”.
Caution
VRF system piping is customized for each installation.
The Lennox VRF Selection Software (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.

3
Unit Dimensions - inches (mm)
A
BOTTOM VIEW
TOP VIEW
26-3/4 (679) 37-3/8 (949)
30-3/4 (781)
37-3/8 (949)
33-1/8 (841)
33-1/8 (841)
2-3/4 (70)
GAS
PIPE
LIQUID
PIPE
DRAIN
CONNECTION
1-1/4 (32)
4-1/8
(105)
6 (152) dia.
SECONDARY
SUPPLY
DUCT
CONNECTION
3/4 (19)
5-3/4
(146)
GAS
PIPE
LIQUID
PIPE
1-3/4 (44)
SIDE VIEW
34-5/8 (879)
(Ceiling Opening)
AIR
OUTLET
AIR
INLET
AIR
OUTLET
LEVELING
ADJUSTMENT
NUT(4)
INSTALLATION
HANGERS (4)
DIFFUSER
PANEL
CEILING
DRAIN PIPE
BOTTOM (PANEL) VIEW
SIDE VIEW
LIQUID
PIPE
GAS
PIPE
DRAIN
CONNECTION
2-3/4 (70) dia.
FRESH AIR
INTAKE
4 (102) dia.
SECONDARY
SUPPLY
DUCT
CONNECTION
4 (102) dia.
SECONDARY
SUPPLY
DUCT
CONNECTION
RECEIVER
Size A
in. mm
009, 012 9 229
015, 018, 024, 030, 036, 048 11-7/8 302
NOTE - Horizontal installation only.

4
Clearances
36
(914)
36
(914)
36
(914)
36
(914)
Minimum Vertical Clearances:
Minimum Clearance from Structural Ceiling to Drop Ceiling:
10-1/4 inches (260 mm) - 007, 009, 012, 015 models
13 inches (330 mm) - 015, 018, 024, 030, 036, 048 models
Minimum Clearance to Floor: 90 inches (2286 mm)
Maximum Clearance to Floor: 160 inches (4064 mm)
Minimum Service Clearance for refrigerant and drain lines - 24 inches (610 mm)
Typical cassette body shown, actual unit may vary.

5
Indoor Unit Placement
AVOID
Do not install the unit in the following locations:
• Areas exposed to salt or other corrosive materials or
caustic gases
• Areas exposed to extreme voltage variations (such as
factories)
• Tightly enclosed areas that may impede service of the
unit.
• Areas exposed to strong electromagnetic forces
• Areas exposed to acids or alkaline detergents (laundry
rooms)
DO:
• Locate the unit so that it is central to the area being
conditioned.
• Locate the unit so that it is not exposed to direct
sunlight.
• Locate the indoor unit so that the room can be
uniformly cooled. Install unit at least 90 inches (2286
mm) above the oor, if possible, for best performance.
• Select a structural location that can support the
suspended weight of the unit’s chassis.
• 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 (lter must able to be removed from
the bottom of the unit).
• Install the indoor 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 between 90 in. (2286
mm) and 156 in. (3962 mm) above the oor to ensure
maximum performance.

6
Cassette Base Installation
It is important to locate the cassette unit in the center of
the area that is being conditioned. This will provide the
best air distribution.
1. If the unit is to be installed in an application that
includes a drop-down tile ceiling, remove the ceiling
tiles necessary to accommodate installation of the
four-way cassette. Before removing the drop ceiling
support grid, use a plumb line or laser device to
identify the center point of the structural ceiling. Make
sure that the ceiling is supported before removing
any of the support grid. It may be necessary to add
extra support to maintain the structural integrity
of the drop ceiling.
2. If the unit is to be installed in an application that
includes a sheet rock (plasterboard) ceiling, the
installation site must be carefully measured and the
sheet rock must be cut to accommodate the cassette
unit. First, identify the center point of the installed
cassette. Use a plumb line to transfer the center mark
to the oor for future use. Use the provided template
to mark the area of the required opening. Carefully cut
the required opening. Make sure that the removal
of the required ceiling support does not a󰀨ect
the structural integrity of the ceiling. It may be
necessary to add extra support.
3. Use the unit as a template or use the provided paper
template to mark the location of the hanging brackets
on the oor. Use a plumb line or a laser to transfer the
bracket positions to the main structural ceiling.
4. Make sure that structure within ceiling void
such as a sub-oor or crawl space is able
to support the weight of the cassette unit.
It may be necessary to add extra support.
If the structural support is constructed of
concrete, install anchors to accept four ⅜”
threaded rods to suspend the cassette base.
If the structural support includes wooden joists,
use angle iron or a 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 1.
5. 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 cassette
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 cassette
base 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.
Figure 1. 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
L
⅜” to ½”
UNIT CHASSIS
DROP CEILING
LEVELING NUT
⅜” THREADED
ROD
SUSPENSION
BRACKET
STRUCTURAL
SUPPORT
Figure 2. Suspension Hardware
6. Iftheunit is being installed in an applicationthat 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).
7. Access is required during the commissioning process
to test the condensate disposal system (See Figure
9), to check the electronic expansion valve and
associated are nuts (See Figure 3), and to check the
local disconnect. Ceiling framing should not restrict
access.

7
Refrigerant Piping Connections
WARNING
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.
Field piping consists of two copper lines connected to the
indoor unit. Table 1 lists the connection sizes at the indoor
unit. The connections are made using the provided brass
are nuts at the end of the refrigerant piping connections.
Both lines must be individually insulated.
1. The seal on the unit refrigerant piping connections
should remain in place until the last possible moment.
This will prevent dust or water from getting into the
refrigerant piping before it is connected.
2. Slowly loosen one of the are nuts to release the
factory nitrogen charge.
3. Remove the are nuts from the connections on the
unit and discard the seal from each of the piping
connections.
4. Slide the are nuts onto the ends of the eld-provided
refrigerant piping before using a suitable aring tool
to are the end of the copper pipe.
5. Apply recommended HFC-410A refrigerant lubricant
to the outside of the ared refrigerant lines (Figure
3-A).
6. Align the threaded connections with the ared
refrigerant lines. Tighten the are nuts lightly at rst to
obtain a smooth match (Figure 3-B).
7. Once snug, continue another half-turn on each nut
which should create a leak-free joint. A torque wrench
may be used to tighten are nuts using Table 2
recommendations. See Figure 4. Do not over-tighten
a ared joint. Flared connections should always
be accessible and must be insulated to prevent
condensation.
IMPORTANT!
The compressor in this unit contains PVE
oil (Polyvinylether). PVE oil is formulated for
hydrouorocarbon (HFC) refrigerants, such as R-410a,
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.
Nominal
Capacity
(Btuh)
Liquid Line
in.
Vapor Line
in.
9000
12000
15000
1/4 1/2
18000
24000
30000
36000
48000
3/8 5/8
Table 1. Refrigerant Piping Connections
A
B
APPLY REFRIGERANT LUBRICANT
ON THE OUTSIDE OF THE FLARE
MALE FLARE
CONNECTION
Figure 3. Making Connections
(Male to Female Connection)
8. After refrigerant piping has been installed and
checked for leaks, apply insulation over all ared joints
ensuring an air tight seal has been made between unit
connections and eld supplied insulated piping. All
eld piping connections shall be insulated and air tight
to prevent unwanted condensation build-up. Figure 5.

8
Flared connections should always be accessible
and must be insulated to prevent condensation.
See Figure 5.
Always use two wrenches when tightening are
nuts to avoid twisting refrigerant piping. DO NOT
over-tighten are nuts.
Outside
Diameter
Recommended
Torque
No torque wrench
available
Finger tighten and
use an appropriately
sized wrench to turn an
additional:
Inches U.S.
1/4” 15 ft.-lb. 1/4 turn
3/8” 26 ft.-lb. 1/2 turn
1/2” 41 ft.-lb. 7/8 turn
5/8” 48 ft.-lb. 1 full turn
Table 2. Flare Nut Torque Recommendations
IMPORTANT
UNIT
BASE
INSULATE ALL FLARED CONNECTIONS
TO PREVENT CONDENSATION
Figure 5. Insulate Flared Connections
IMPORTANT!
Figure 4. Tighten Flare Nut
To Indoor Unit
Torque Wrench
Backup
Wrench
To Outdoor Unit
IMPORTANT
Support ALL piping within 12 in. (305 mm) of any
mechanical tting such as a ared connection.

9
IMPORTANT!
Drain should have a slope of at least ¼ inch per foot
and should be approved corrosion-resistant pipe. You
must conrm operation of every drain and pump in the
system as part of the commissioning procedure.
Figure 8. Test Condensate Drain
Drain Plug
Drain Pan
Cassette Base
Pour water
here for test
Cap
(Remove for test)
1. Use the provided hose clamp to secure the provided
exible condensate drain connector to the drain line
stub on the side of the cassette base. Wrap the exible
connector with the provided insulation. NOTE - Take
care not to over-tighten the hose clamp as 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. Use 1-1/4” OD PVC pipe for
the drain line.
3. See Figure 6 for applications including a single unit
and a single 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.
4. See Figure 7 for applications including multiple units
using the internal 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) and that each individual drain is
connected to the main drain exactly as shown.
5. Drain should be as short as possible and should
not have any droops or kinks that would restrict
condensate ow and shall be approved resistant pipe.
Cassette
Unit
2~3-15/16 in.
Max. 28 in.
2~3-15/16 in.
2~3-15/16 in.
MAIN DRAIN
(slope of at least ¼ inch per foot)
INDIVIDUAL DRAIN OUTLET
FROM EACH INDOOR UNIT
(Must be connected to internal
pump and must be routed to
main drain as shown.)
Cassette
Unit
Cassette
Unit
8 in.8 in.8 in.
Max. 28 in.
Max. 28 in.
Figure 7. Using a Main Drain to Serve Multiple Indoor Units
Condensate Piping Connections
CAUTION
Make sure that drain piping is properly routed
and insulated in order to prevent both leaks and
condensation.
Supports
Drain Line
Drop Ceiling
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.
3 ft.
(1 m)
1 ft.
(305 mm)
max
Figure 6. Sloped Condensate Drain -- Single Unit
6. After system installation is complete, the condensate
drain line must be checked for leaks and the
condensate pumps must be checked to ensure proper
operation. This check is part of the commissioning
sequence. Pour water into the evaporator drain pan
to ensure proper condensate drainage. See Figure 8.
If a leak is found, shut down power to the unit at once
and do not restore power to the unit until the problem
has been resolved.

10
Wiring Connections
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.
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.
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.
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.
2. Locate the terminal strip in the control box. Connect
the power wiring (sized per NEC/CEC and local
codes) and communications cable (per Figures 10, 11
and 12. Refer to unit nameplate for rated voltage.
Figure 9. Typical Wiring Diagram V33B Wiring Diagram
Typical wiring diagram. Refer to wiring diagram on the unit for actual wiring.
Main board
HA
HB
To wired
controller
comm. bus
T2B
T1T2A
XS1-XS4
XP1-XP4
BLUE WHITE
RED
XS7
XP7
XS6
XP6
XS5
XP5
CN2
POWER IN
Attention:
For the convenience of
wiring, the
communication
terminals can be pulled
out from the main board.
CS
CN12
To outdoor/
indoor/MS
units comm. bus
BLUE RED
CN3 CN18
XT1
FM
ALARM
CN24 CN52
CN9
EEV
CN21 CN5
CN8
CN51
CN50
CN51
HHE interface
T2A
Outlet pipe temp. sensor
Inlet pipe temp. sensor
T2B
Indoor fan motor
Room temp. sensor
T1
FM
Code Title
XS1-7
XP1-7
EEV
Connectors
Terminal
Pump motor
Water level switch
Swing motor
Warning lamp
Electronic expansion valve
XT1
PUMP
CS
ALARM
Connectors
GM
Error code
Error Content
E0
E1
E2
E4
E5
Mode conflict
Comm. error with outdoor unit
Temp. sensor (T1) error
Temp. sensor (T2B) error
Temp. sensor (T2A) error
Error Content
Error code
FE
Eb
U4
Ed
EE
F8
No address when first time power on
EEV error
MS error in auto system-check mode
Outdoor unit error
Water level alarm
MS error
E6
DC fan error
E7
EEPROM error
PUMP
GM GM
Display board
CN15
L1 L2
Y/G
FAN
CTON HTON
AUXH
( Current range: 0-1A)
( Voltage range: 0-24V AC/DC)
CN54
ON/OFF
SWITCH
Occupancy
sensor
“ +5V GND +12V ”
ONLY USED
FOR TESTING
CN11
P (COM) Q HA (12V) HB
P
Q
12V
COM
BLACK
CN26
T2
T2
Midlet pipe temp. sensor
E3
Temp. sensor (T2) error
D8
A0
Remote OFF
Emergency stop
CN22
CN14
To wired
controller
power
NOTE:
1. Refer to manual for com-
munication wiring
2. Please use the 2-conductor
shielded cable

11
Figure 10. 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.

12
Figure 11. 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 shields of shielded cable connect to chassis GROUND terminal at MS Boxes and Indoor Units.
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 cable shield
to MS Box
and Indoor Unit chassis
Install a terminating resistor (Ω120) on terminals P&Q on the indoor unit
which is furthest from the outdoor unit..

13
Figure 12. Typical Communication Wiring Diagram (VRF Heat Pump System)
Tightening torque for the terminal screws
• Use the correct screwdriver for ghting the terminal
screws. If the screwdriver blade is too small, the head
of the screw might be damaged, and the screw will
not be properly tightened.
• If the terminal screws are over tightened, screws
might be damaged.
• Refer to the table below for the tightening torque of
the terminal screws.
• After wiring, conrm all connections are correct; Then
turn on power supply to the unit.
Table 3. 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
(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

14
Outside Air Connection Supply Air Congurations
A limited amount of ltered outside air can be brought into
the cassette unit [through the 3 inch (76 mm)] outside air
knockout to be conditioned and mixed into the supply air.
Figure 14. Typical Outside Air Supply Channel
Figure 13. Typical Outside Air Knockout
Outside
Air
Knockout
Outside
Air
Supply
Channel
1. Knock out the outside air supply opening. See Figure
13.
2. Remove any insulation.
3. Make sure the outside air supply channel is clear of
styrofoam and debris. See Figure 14.
4. Connect the outside air duct to cassette body using
the four screw holes shown in Figure 13.
Supply air is typically provided from all four sides of the
cassette unit. See Figure 15.
If needed for the application, one or two sides of the
cassette supply air can be blanked o󰀨 to prevent air ow
from that side. See Figures 16 and 17 for possible air ow
congurations.
Use eld-provided blocking and sealing materials.
Materials must be listed ANSI/UL and ASTM E 84
approved.
NOTE - A maximum of two sides can be blanked o.
1. Remove the decorative cover panel if installed.
2. Identify and measure the supply air opening that will
be blanked o󰀨. See Figure 15.
3. Prepare the blocking material. Cut a piece of
styrofoam or other non-conductive material to t the
supply air opening.
4. Insert the blocking material into the supply air opening.
5. Prepare the sealing material. Cut a piece of tape or
other non-conductive sealing material to cover and
secure the blocking material.
6. Seal the supply air opening using the sealing material.
7. Install the decorative cover panel.
5. Relocate the indoor unit’s return air sensor to either
the controller (electronically) or physically by using
the remote sensor accessory.
6. The outside air supply duct length must be 10 feet or
less.
7. Use a eld-supplied booster fan to increase static
pressure.
Figure 15. Typical Supply Air Conguration
Typical cassette body shown, actual unit may vary
in size and location of supply air openings.
Typical cassette body shown, actual unit may vary in
size and location of supply air channel.
Duct
Screw
Holes (4)

15
Figure 16. Three-way Outlet Possible Flow Patterns
Figure 17. Two-way Outlet Possible Flow Patterns
Typical cassette body shown, actual unit may vary.

16
Installation of Secondary Supply Duct
Figure 18. Typical Duct Knockout
A limited amount of conditioned air can be diverted
through a small duct to a location outside of the zone. For
example, a common application is for the cassette unit to
serve an o󰀩ce that has a small attached bathroom. Air
can be supplied to the bathroom from the cassette unit by
following these instructions.
NOTE - Secondary supply duct knockouts are located on
all four sides of the V33B cassette body. If the knock out
is used, the supply air opening of the same side should be
blocked and sealed.
1. Decide which side of the cassette body will be ducted.
2. Seal the supply air outlet on the side to which the duct
will be attached. See the Supply Air Congurations
section for detailed instructions.
3. Knockout the secondary supply duct opening. See
Figure 18.
4. Remove any insulation.
5. Connect the secondary supply duct to the cassette
body using the eight screw holes shown in gure 18.
6. A eld-supplied duct transition may be required. Be
sure there is an air-tight seal between the transition
and the cassette body and between the transition and
the secondary supply duct.
7. The secondary supply duct must be 4 or 6 inches
in diameter and 10 feet or less in length (including
transitions).
NOTE - A eld-supplied volume control damper can be
used to control the amount of air supplied to the space,
however, the area being conditioned by the secondary
supply duct will not have control over the temperature of
the air being supplied.
Duct Knockouts
Supports
Drop Ceiling
NOTE - The secondary supply duct must be 4 or 6 inches in diameter and 10 feet or less
in length (including transitions).
Supply Duct
10 feet maximum
Seal supply air outlet on duct side
Typical cassette body shown, actual unit may vary in
size and location of secondary duct knockouts.
Figure 19. Supply Duct Maximum Length

17
Cassette Cover Panel Installation
1. Carefully remove the cassette cover panel from its
protective packaging and place the panel di󰀨user-
side-out on a clean, level surface.
CORNER ACCESS
COVER
Remove screws andloosen
straps to remove corner
covers from panel.
LATCH RELEASE
BUTTONS
45º
Press latch release
buttons at the same
time to release latch.
Tilt return air grille outward,
then, lift to remove grille
from panel.
Figure 20. Remove Return Air Grille
CAUTION
Do not place the cover panel with the di󰀨users face
down on the oor or other surface. Louvers will be
damaged if pressure is applied to them.
2. Press the two grille latch release buttons at the same
time to release the grille. See Figure 20. Tilt the return
air grille outward at a 45º angle and lift the grille away
from the panel. Carefully place the return air grille o󰀨
to the side.
3. Remove access covers from each corner of the panel.
See Figure 21.
Figure 21. Remove Corner Covers
4. Position the ceiling panel so that the arrow on the panel
is aligned with the arrow sticker on the cassette base
(both arrow stickers should be on the same side of the
cassette base). NOTE - If the panel and the base are
not properly aligned, the airow will be blocked and
the harness plugs from the panel to the cassette base
will not be long enough to plug together.
5. Locate the cover panel hangers on the two corners
with the louver swing motors. Place these two
hangers on the corresponding hooks on the corners
of the cassette base. See detail A in Figure 22. Then,
place the other hangers from the other two corners
over their corresponding hooks on the cassette base
as shown in detail B in Figure 22.
6. Connect the six-pin harness plugs from each of the
two swing motors to the matching six-pin plugs from
the control box in the cassette base.
7. Connect the black harness from the display on the
cover panel to the corresponding black plug from the
control box in the cassette base.
NOTE - Cover panel must be ordered as a separate accessory.

18
air out
5/32-1/4 (4-6 mm)
CASSETTE BASE
CEILING
FOAM
INSULATION
COVER PANELSUPPLY AIR
LOUVER
FOAM
INSULATION
Side View Cutaway
3/8”
≥3/4(19)
1-3/4
(44)
5-3/4
(146)
CASSETTE
BASE
COVERPANEL
CEILING
LEVELING
NUT
THREADED
ROD
REFRIGERANT
PIPING CONNECTIONS
CONDENSATE
CONNECTION
DRAIN
CASSETTE BASE
HOOK
HANGER
DETAIL A
PHILLIPS
SCREWDRIVER
COVER PANEL
SECURING
SCREW
DETAIL B
DETAIL C
COVER PANEL
LOUVER SWING
MOTORS
Figure 22. Install Cover Panel
Figure 23. Cover Panel in Place
8. Tighten the provided screws in the bracket in the
cover panel immediately below each panel hanger.
See detail C in Figure 22. Adjust the cover panel by
turning slightly clockwise, if necessary, to make sure
that the panel is properly aligned with the cassette
base.
9. Continue to tighten the cover panel securing screws
until the insulation between the cover panel and the
cassette base has been compressed to approximately
¼”. The cover panel must form a seal with the ceiling
and the cassette base around the entire perimeter of
the unit. See Figure 23.
10. If it is necessary to adjust the cassette height after the
cover panel has been installed, access the leveling
nut through the removable access cover on each
corner. See Figure 24.
11. The return air grille must be reinstalled on the cover
panel. Align the four tabs on the grille with the four
slots in the cover panel. Tilt the panel back into place.
Press the opposite side of the cover gently until the
latches engage.
CORNER PANEL
LOOSEN UPPER NUT
TIGHTEN LOWER NUT
Figure 24. Adjust Unit Height Through Corner Panel

19
Network Address and Commissioning
After the system has been installed, each indoor unit must
be assigned an address as part of the commissioning
procedure.
Use the Spot Check Performance tables below and the
Manual button on the unit receiver to view diagnostic
information the indoor unit.
Table 4. Spot Check Performance Identication Table
Spot Check Instructions
This Spot Check Performance table is located on the unit service panel.
The diagnostic information can also be obtained using the wired remote controller.
Digital Display
The indoor unit is equipped with a receiver that has a digital
display that provides an error code. Refer to the table
below to view the error codes. The error code will replace
the temperature setting displayed on the receiver. If more
than one error has occurred, the codes will alternate so
that all codes are shown.
Make note of the code (E1, EE, etc.), then reset the display
by pressing the ON/OFF button on the unit controller.
Press the ON/OFF button a second time to reapply power
to unit. If the code is still displayed, disconnect and restore
power at the unit disconnect switch or circuit breaker. If
the problem was temporary, the code will not reappear.
If the error code reappears after power has been broken
and restored at the disconnect switch or circuit breaker,
call VRF Technical Support 1-844-438-8731.
Troubleshooting
Figure 25. Cover Panel
Receiver/Display
No. Content Recorded Value/Date
0 Normal display
1 Communication address of indoor unit
2Indoor unit capacity (horsepower)
3 Network address of indoor unit
4 The actual setpoint temperature
5 The actual indoor temperature T1
6 The middle coil temperature T2
7 The coil inlet temperature T2A
8 The coil outlet temperature T2B
9 The actual superheat temperature
10 The actual subcool temperature
11 Error Code
12 Indoor software version
13 End (--)

20
Technical Support
1-844-GET-VRF1
(1-844-438-8731)
[email protected]
www.LennoxVRF.com
Download the app
from the Apple App Store or the Google Play store.
Error Code Description
FE No address
E0 Mode conict
E1 Communication error between indoor and main outdoor unit
E2 T1 (Room temperature sensor) malfunction
E3 T2 (Middle of evaporator sensor) malfunction
E4 T2B (Outlet of evaporator sensor) malfunction
E5 T2A (Inlet of evaporator sensor) malfunction
E6 DC fan motor error
E7 EEPROM failure
Eb EXV malfunction
Ed Outdoor unit Fault
EE High Water Alarm
A0 Emergency stop
D8 Remote o󰀨
U4 MS self-inspection error
F8 MS error
Table 8. Fault Code Display on Controller
Error Code Description
F0 Communication/Address error between indoor units and wired controller
F1 Communication/Wiring error between indoor units and wired controller
E2 Controller temperature sensor error
Table 7. Fault Code Display on Indoor Unit Receiver