INSTALLATION
E2011 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.
Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.
CAUTION
Physical contact with metal edges and corners while
applying excessive force or rapid motion can result in
personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.
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.
INSTRUCTIONS
Elite® Series CBX27UH
Units
MULTI−POSITION AIR HANDLERS
506294−01
07/11
Supersedes 05/11
Table of Contents
CBX27UH Up−flow/Down−flow Unit Dimensions 2. . .
CBX27UH Horizontal LH/RH Unit Dimensions 3. . . .
General Information 4. . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . .
Requirements 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing the Unit 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brazing Connections 6. . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing the Condensate Drain 7. . . . . . . . . . . . . . . . .
Inspecting and Replacing Filters 8. . . . . . . . . . . . . . . . .
Sealing the Unit 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measuring Static Pressure 9. . . . . . . . . . . . . . . . . . . . .
Adjusting the Blower Speed 9. . . . . . . . . . . . . . . . . . . .
Making Electrical Connections 11. . . . . . . . . . . . . . . . . .
Repairing or Replacing Cabinet Insulation 15. . . . . . . . .
Litho U.S.A.
IMPORTANT INFORMATION TO INSTALLER
BLOWER HOUSING
SUPPORT PAD
HORIZONTAL DRAIN PAN (SEE PAGES 4
AND 6)
CHECK FOR AND REMOVE THE FOLLOWING ITEMS BEFORE OPERATING UNIT.
TOP CAP SHIPPING
BRACKET (REPLACE
SCREWS IN TOP CAP
AFTER REMOVAL)
REFRIGERANT LINE PLUGS
D
(SEE PAGE 6)
DRIP SHIELD FOR −060 UNITS ONLY
HORIZONTAL APPLICATIONS (SEE
PAGE 5).
D
07/11 506294−01
*2P0711* *P506294-01*
Page 1
CBX27UH Up−flow and Down−flow Unit Dimensions − Inches (mm)
3/4 (19)
SUPPLY AIR
OPENING
D
11-1/16 (281)
LINE VOLTAGE
INLETS (TOP
AND LEFT SIDE)
TOP VIEW
3/4 (19)
LOW VOLTAGE
INLETS (TOP AND
RIGHT SIDE)
5/8 (16)
BC
AIR
FLOW
G
OPTIONAL
ELECTRIC HEAT
(FIELD−INSTALLED)
A
SUCTION
H
RETURN AIR
5/8 (16) 1 (25)
F
FRONT VIEW
FILTER ACCESS
5/8 (16)
UP−FLOW POSITION
LINE
LIQUID
LINE
FILTER
2
COIL
E
2-3/4
(70)
5/8 (16)
PIPING PLATE DETAIL
1-3/4 (44)
FILTER
SUCTION
LINE
LIQUID
LINE
OPTIONAL
ELECTRIC HEAT
(FIELD−INSTALLED)
LOW VOLTAGE
(RIGHT SIDE)
LINE VOLTAGE
(LEFT SIDE)
4-3/8 (111)
SUCTION LINE
CONDENSATE DRAINS
(2) (HORIZONTAL)
LIQUID LINE
CONDENSATE DRAINS
(2) (UP−FLOW AND
DOWN−FLOW)
3-1/2 (89)
11-1/16 (281)
(FOR UP−FLOW AND DOWN−FLOW POSITIONS)
1-1/8 (29)
(51)
5-3/8
(137)
BLOWER
RETURN AIR
SIDE VIEW
C
COIL
BLOWER
SUPPLY
AIR
SIDE VIEW
5/8 (16)
5/8 (16)
5/8 (16)
DOWN−FLOW POSITION
5/8 (16)
F
Air Opening
E
1 (25)
TOP VIEW
B
AIR FLOW
SUPPLY AIR
D
FRONT VIEW
5/8 (16)
Return
FILTER ACCESS
H
A
G
5/8 (16)
CBX27UH Common Dimensions − Inches (mm)
Dim. −018/−024 −030/−036 −042/−048 −060
A
B
C
D
E
F
G
H
49−1/4 (1251) 51 (1295) 58−1/2 (1486) 62-1/2 (1588)
21−1/4 (540) 21−1/4 (540) 21-1/4 (540) 21-1/4 (540)
20−5/8 (524) 22-5/8 (575) 24−5/8 (625) 24−5/8 (625)
19−3/4 (502) 19−3/4 (502) 19-3/4 (502) 19-3/4 (502)
19 (483) 21 (533) 23 (584) 23 (584)
20 (508) 20 (508) 20 (508) 20 (508)
24−5/8 (625) 26-3/8 (670) 27-7/8 (708) 27-7/8 (708)
24−5/8 (625) 24−5/8 (625) 30−5/8 (778) 34-5/8 (879)
Page 2
506294−01
CBX27UH Horizontal Left− and Right−Hand Unit Dimensions − Inches (mm)
5-3/8
(137)
CONDENSATE
DRAINS (2)
(UP−FLOW
AND
DOWN−FLOW)
CONDENSATE
DRAINS (2)
(HORIZONTAL)
PIPING PLATE
DETAIL
5/8 (16)
5/8 (16)
5/8 (16)
5-3/4
(46)
E
RETURN AIR
OPENING
F
END VIEW
Horizontal Position
(Left-Hand Air
Discharge)
1-3/4
(44)
(51)
2
1-1/2
(38)
1 (25)
FILTER ACCESS
LIQUID
LINE
SUCTION
LINE
1-1/8
(29)
4-3/8
(111)
FILTER
Horizontal Position
(Right-Hand Air
Discharge)
Coil
LIQUID
SUCTION
LINE
LINE
TOP VIEW
A
H
AIR
FLOW
FRONT VIEW
C
BLOWER
BLOWER
OPTIONAL ELECTRIC
HEAT (FIELD−INSTALLED)
G
Coil
5/8 (16)
B
INLETS (BOTTOM
C
LINE VOLTAGE
INLETS (TOP
AND RIGHT
SIDE)
LOW VOLTAGE
AND RIGHT
SIDE)
FOR DIMENSIONS A" THROUGH
H", SEE CHART ON PAGE 2.
11-1/16
3/4 (19)
(281)
Supply
4-3/8
(111)
1-1/8
(29)
Air
Opening
END VIEW
D
3/4 (19)
3/4 (19)
SUCTION LINE
PIPING PLATE
DETAIL
LIQUID
LINE
1 (25)
Return
Air Opening
END VIEW
2
5-3/8
(51)
(137)
5/8 (16)
E
F
5/8 (16)
5/8 (16)
3/4 (19)
3/4 (19)
LOW VOLTAGE
3/4 (19)
11-1/16
(281)
Supply
D
Air Opening
LINE VOLTAGE INLETS
(BOTTOM AND LEFT SIDE)
END VIEW
INLETS (TOP AND
LEFT SIDE)
OPTIONAL ELECTRIC
HEAT (FIELD INSTALLED)
5/8 (16)
B
CONDENSATE DRAINS (2)
(HORIZONTAL)
G
Air Flow
FILTER
TOP VIEW
A
FRONT VIEW
SUCTION
LINE
H
1-3/4
(44)
LIQUID
LINE
5-3/4
(146)
FILTER ACCESS
1-1/2 (38)
WARNING
This product and/or the indoor unit it is matched with may contain fiberglass wool.
Disturbing the insulation during installation, maintenance, or repair will expose you to fiberglass wool dust. Breathing this
may cause lung cancer. (Fiberglass wool is known to the State of California to cause cancer.)
Fiberglass wool may also cause respiratory, skin, and eye irritation.
To reduce exposure to this substance or for further information, consult material safety data sheets available from address
shown below, or contact your supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
Page 3
CBX27UH SERIES
General Information
The Elite® CBX27UH series air handler is designed for
installation with optional field−installed electric heat and a
matching HFC−410A outdoor unit
This instruction is intended as a general guide and does
not supersede local or national codes in any way. Consult
authorities having jurisdiction before installation. Check
equipment for shipping damage; if found, immediately
report damage to the last carrier.
Shipping and Packing List
Package 1 of 1 contains the following:
1
Assembled air handler unit
Horizontal drip shield (CBX27UH−60 only)
1
NOTE − For down−flow applications, order kit number
83M57.
Requirements
IMPORTANT
This unit must be matched with an indoor coil as specified in Lennox Engineering Handbook. Coils previously charged with HCFC−22 must be flushed.
In addition to conforming to manufacturer’s installation
instructions and local municipal building codes, installation
of Lennox air handler units (with or without optional electric
heat), shall conform with the following National Fire
Protection Association (NFPA) standards:
To disassemble:
1. Remove access panels.
2. Remove both blower and coil assemblies. This will
lighten the cabinet for lifting.
3. Remove one screw from the left and right posts inside
the unit. Remove one screw from each side on the
back of the unit. Unit sections will now separate.
To reassemble:
1. Align cabinet sections together.
2. Reinstall screws.
3. Replace blower and coil assemblies.
4. Replace access panel.
UP−FLOW APPLICATION
Use the following procedures to configure the unit for
up−flow operations:
1. Remove access panels.
2. Remove and discard the horizontal drip shield (−060
model, used only on horizontal applications) and the
corrugated padding between the blower and coil
assembly.
3. The horizontal drain pan must be removed when the
coil blower is installed in the up−flow position.
Removing horizontal drain pain will allow proper
airflow and increase efficiency.
4. After removing horizontal drain pan, place the unit in
desired location. Set unit so that it is level. Connect
return and supply air plenums as required using sheet
metal screws as illustrated in figure 1.
5. Install units that have no return air plenum on a stand
that is at least 14" from the floor to allow for proper air
return. Lennox offers an optional up−flow unit stand as
listed in table 1.
S NFPA No. 90A − Standard for Installation of Air
Conditioning and Ventilation Systems
S NFPA No. 90B − Standard for Installation of Residence
Type Warm Air Heating and Air Conditioning Systems
This unit is approved for installation clearance to
combustible material as stated on the unit rating plate.
Accessibility and service clearances must take
precedence over combustible material clearances.
Installing the Unit
These units are factory−configured for up−flow and
horizontal right−hand discharge installation. For down−flow
or horizontal left−hand discharge, certain field
modifications are required.
DISASSEMBLE/REASSEMBLE AIR HANDLER UNITS
The air handler units consists of two factory-assembled
sections. It may be necessary to disassemble the sections
when positioning the unit for installation.
506294−01
Page 4
HORIZONTAL DRAIN PAN
(MUST BE REMOVED)
UP−FLOW/
DOWN−FLOW
DRAIN PAN
Figure 1. Up−flow Configuration
Table 1. Optional Unit Side Stand (Up−Flow Only)
Model Kit Number
−21, −26, and −31 45K31
−41 through −65.
45K32
HORIZONTAL RIGHT−HAND DISCHARGE
APPLICATION
Use the following procedures to configure the unit for
horizontal right−hand discharge operations:
NOTE − For horizontal applications, a secondary drain pan
is recommended. Refer to local codes.
1. Before operating the unit, remove access panels and
the horizontal drip shield (−060 model) and the
corrugated padding between the blower and coil
assembly. Discard the corrugated padding.
2. Install the horizontal shield on the front edge of the
horizontal drain pan as illustrated in figure 2.
3. No further adjustment is necessary. Set unit so that it is
sloped 1/4" towards the drain pan end of the unit.
4. If the unit is suspended, the entire length of the cabinet
must be supported. If you use a chain or strap, use a
piece of angle iron or sheet metal attached to the unit
(either above or below) to support the length of the
cabinet. Use securing screws no longer than 1/2" to
avoid damaging the coil or filter as illustrated in figure
3. Use sheet metal screws to connect the return and
supply air plenums as required.
UPLOAD / DOWN−FLOW
DRAIN PAN
HORIZONTAL DRIP SHIELD (−060 MODELS)
IMPORTANT
When removing the coil, there is possible danger of
equipment damage and personal injury. Be careful when
removing the coil assembly from a unit installed in right−
or left−hand applications. The coil may tip into the drain
pan once it is clear of the cabinet. Support the coil when
removing it.
HORIZONTAL LEFT−HAND DISCHARGE
APPLICATION
NOTE − For horizontal applications, a secondary drain pan
is recommended. Refer to local codes.
TOP CAP ROTATED TO
CORRECT POSITION
TOP CAP SCREWS
CABINET
SUPPORT
DRIP
SHIELD
90º
BEND
HORIZONTAL DRAIN
PAN
No Adjustment Is Necessary
DOWN−FLOW RAIL
Figure 2. Right−Hand Discharge Configuration
HORIZONTAL RIGHT−HAND DISCHARGE
APPLICATION IN HIGH HUMIDITY AREAS
For horizontal applications in high humidity areas remove
the down−flow rail closest to the drain pan.
To remove rail:
1. Remove the screws from the rail at the back of unit and
at the cabinet support rail.
2. Remove the down−flow rail then replace screws.
3. Seal around the exiting drain pipe, liquid line, and
suction line to prevent humid air from infiltrating into
the unit.
1/2 in. Screws Maximum
ANGLE IRON OR
SHEET METAL
electrical inlet clearance 4 in.
(102 mm)
DRAIN PAN
reinstalled here
DRAIN plugs
reinstalled here removed from here
Coil shown in upload position for easy conversion
TOP
CAP
90º
BEND
DRAIN PAN
SHIPPING
LOCATION
Align holes
with holes in
coil end plate.
back coil end
seal
Figure 4. Field Modification for Left−Hand Discharge
Use the following procedures to configure the unit for
horizontal left−hand discharge operations:
1. Before operating the unit, remove access panels and
the horizontal drip shield (−060 model) and the
corrugated padding between the blower and coil
assembly. Discard the corrugated padding.
2. Pull the coil assembly from unit. Pull off the horizontal
drain pan.
3. Remove the drain plugs from back drain holes on
horizontal drain pan and reinstall them on front holes.
FRONT VIEW END VIEW
Figure 3. Suspending Horizontal Unit
IMPORTANT
After removal of drain pan plug(s), check drain hole(s) to
verify that drain opening is fully open and free of any
debris. Also check to make sure that no debris has fallen
into the drain pan during installation that may plug up the
drain opening.
Page 5
CBX27UH SERIES
4. Rotate drain pan 180º front-to-back and install it on the
opposite side of the coil.
5. Remove screws from top cap. Remove horizontal drip
shield screw located in the center of the back coil end
seal as illustrated in figure 4 on page 5.
6. Rotate horizontal drip shield 180º front to back.
7. Remove plastic plug from left hole on coil front end
seal and reinstall plug in back hole. Reinstall horizontal
drip shield screw in front coil end seal. Drip shield
should drain downward into horizontal drain pan inside
coil.
HORIZONTAL DRIP SHIELD (−060 MODEL)
DOWN−FLOW
RAIL
Figure 5. Left−Hand Discharge Configuration
8. Rotate top cap 180º front-to-back and align with
unused screw holes. Holes must align with front and
back coil end plates. The top cap has a 45º bend on
one side and a 90º bend on the other. The 90º bend
must be on the same side as the horizontal drain
pan as illustrated in figure 4 on page 5.
NOTE − Be very careful when you reinstall the screws into
coil end plate engaging holes. Misaligned screws may
damage the coil.
9. From the up−flow position, flip cabinet 90º to the left
and set into place. Replace blower assembly. Secure
coil in place by bending down the tab on the cabinet
support rail as illustrated in figures 4 and 5.
10. Install the horizontal shield (−060 model) on the front
edge of the horizontal drain pan as illustrated in figure
5 on page 6.
NOTE − For horizontal applications in high humidity
areas, remove the down−flow rail closest to the drain pan.
To remove rail, remove screw from rail at back of unit and
at cabinet support rail. Remove down−flow rail then replace
screws. Also, seal around the exiting drain pipe, liquid and
suction lines to prevent infiltration of humid air.
11. Knock out drain seal plate from access door. Secure
plate to cabinet front flange with screw provided.
12. Flip access door and replace it on the unit.
13. Set unit so that it is sloped 1/4" toward the drain pan
end of the unit. Connect return and supply air plenums
as required using sheet metal screws.
FRONT EDGE OF HORIZONTAL
DRAIN PAN
14. If suspending the unit, it must be supported along the
entire length of the cabinet. If using chain or strap, use
a piece of angle iron or sheet metal attached to the unit
(either above or below) so that the full length of the
cabinet is supported. Use securing screws no longer
than 1/2" to avoid damage to coil or filter. as illustrated
in figure 3 on page 5. Connect return and supply air
plenums as required using sheet metal screws.
DOWN−FLOW APPLICATION
NOTE − If down−flow application is required, separately
order kit number 83M57 and install per kit’s instructions.
Also use metal or class I supply and return air plenums.
Use the installation instruction provided with the downflow
kit.
IMPORTANT
If electric heat section with circuit breakers
(ECB29/ECB31) is applied to down−flow and CBX27UH
units, the circuit breakers must be rotated 180° to the UP
position. See ECB29/ECB31 installation instructions for
more details.
Brazing Connections
IMPORTANT
To prevent the build up of high levels of nitrogen when
purging, be sure it is done in a well ventilated area. Purge
low pressure nitrogen (1 to 2 psig) through the refrigerant
piping during brazing. This will help to prevent oxidation
and the introduction of moisture into a system.
All coils are equipped with a factory−installed, internally
mounted check/expansion valve.
The air handler’s coil line sizes are listed in table 2. Use
Lennox L15 (sweat) series line sets (refer to the outdoor
unit Engineering Handbook for proper size, type and
application). For field−fabricated refrigerant lines, see the
piping section of the Lennox Unit Information Service
Manual.
WARNING
Danger of explosion!
Can cause equipment damage, injury, or
death.
When using a high pressure gas such as
dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator
that can control the pressure down to 1 or
2 psig (6.9 to 13.8 kPa).
506294−01
Page 6
AIR HANDLER UNIT
Model
−018
−024
−030
−036
−042
−048
−060
Table 2. Refrigerant Line Sizes
Liquid
Line
3/8"
(10mm)
3/8"
(10mm)
3/8"
(10mm)
Vapor
Line
3/4"
(19mm)
7/8"
(22mm)
7/8"
(22mm)
Line Sets
L15 line set sizes are dependent on unit match−up. See
Engineering Handbook for
outdoor unit to determine correct line set sizes.
Field-fabricated
SUCTION LINE
LIQUID LINE
Figure 6. Brazing Connections
NOTE − CBX27UH series air handlers use nitrogen or
dry air as a holding charge. If there is no pressure when
the rubber plugs are removed, check the coil for leaks
before installing. After installation, pull a vacuum on the
line set and coil before releasing the unit charge into the
system.
NOTE − See outdoor unit instructions on how to flow
nitrogen through line sets.
1. Remove access panel.
2. Remove the refrigerant line caps from the refrigerant
lines.
3. Use a wet rag to protect TXV sensing bulb (or remove
it) when brazing suction line connections.
4. Place a wet rag against piping plate and around the
suction line connection. The wet rag must be in place
to guard against damage to the paint.
5. With the wet rag in place, position a field provided
elbow fitting to the air handler’s suction line and line
set. Start nitrogen flow before brazing.
6. After the procedure is completed then remove the wet
rag.
7. Place wet rag against piping plate and around the
liquid line connection. Position liquid line elbow to air
handler’s suction line and to line set. Start nitrogen flow
and begin brazing both connections and after
procedure is completed then remove both wet rags.
8. Refer to instructions provided with outdoor unit for leak
testing, evacuating and charging procedures.
9. Install access panel.
Installing the Condensate Drain
IMPORTANT
After removal of drain pan plug(s), check drain hole(s) to
verify that drain opening is fully open and free of any
debris. Also check to make sure that no debris has fallen
into the drain pan during installation that may plug up the
drain opening.
MAIN DRAIN
Connect the main drain and route downward to drain line or
sump. Do not connect drain to a closed waste system. See
Figure 8 for typical drain trap configuration.
OVERFLOW DRAIN
It is recommended that the overflow drain is connected to a
overflow drain line for all units. If overflow drain is not
connected, it must be plugged with provided cap.
For downflow orientation, the overflow drain MUST be
connected and routed to a overflow drain line. See Figure 8
for main and overflow drain locations based on coil
orientation.
LEFT−HAND AIR
DISCHARGE
OVERFLOW
DRAIN ON LEFT
Figure 7. Main and Overflow Drain Locations based
UPFLOW OR
DOWNFLOW
on Coil Orientation
RIGHT−HAND AIR
DISCHARGE
MAIN DRAIN ON
RIGHT
Page 7
CBX27UH SERIES
ABOVE
FINISHED
SPACE?
OVERFLOW DRAIN LINE
ALWAYS RUN AN OVERFLOW DRAIN LINE. IF NOT POSSIBLE TO
ROUTE OVERFLOW DRAIN LINE, INSTALL LOW VOLTAGE
OVERFLOW SWITCH KIT. WIRE KIT TO SHUT DOWN
COMPRESSOR PER INSTRUCTIONS.
LENNOX #
X3169
COMPACT OVERFLOW SWITCH WITH 3/4" FEMALE SLIP INLET
NO
AND MALE ADAPTER, TWO PART DESIGN FOR USE WHERE
OBSTRUCTIONS PREVENT DIRECT THREADING
CLEAN OUT
PRESS IN
(DO NOT GLUE)
VENT MUST EXTEND
ABOVE HEIGHT OF
COIL DRAIN PAN BY
TWO INCHES (51MM)
VENT
AIR HANDLER DRAIN PAN
OVERFLOW
DRAIN
YES
NOTE WHEN A AIR HANDLER IS LOCATED ABOVE A FINISHED SPACE THE SECONDARY
DRAIN PAN MUST HAVE A LARGER FOOTPRINT THAN THE AIR HANDLER.
SECONDARY
DRAIN PAN
OPTIONAL
MAIN
DRAIN
SAFETY
PAN
WHEN A COIL IS LOCATED ABOVE A FINISHED SPACE, A 3/4" (19.1MM) SECONDARY DRAIN
LINE MUST BE:
S CONNECTED TO SECONDARY DRAIN PAN
OR
S CONNECTED TO THE OVERFLOW DRAIN OUTLET OF THE AIR HANDLER DRAIN PAN.
TRAPS MUST BE DEEP ENOUGH TO OFFSET MAXIMUM STATIC DIFFERENCES
GENERALLY, TWO INCHES (51MM).
*LENNOX P−TRAP 49P66 REQUIRES A LARGER INSTALLATION SPACE THAN THE J−TRAP 91P90.
Figure 8. Typical Main and Overflow Drain
1" X 3/4" X 3/4"
REDUCING
TEE WITH
PLUG
LENNOX* P−TRAP
49P66, J−TRAP #
91P90 OR ANY
PVC SCH 40 P− OR
J−TRAP 3/4"
TRAP DEPTH
FOR NEGATIVE PRESSURE COILS (BLOWER
AFTER COIL) TRAPS ARE REQUIRED ON ALL
DRAIN LINES CONNECTED TO COIL.
2"
(51MM)
DRAIN LINE SHOULD
SLOPE A MINIMUM OF
ONE INCH PER 10
FEET (25MM PER 3
METERS)
TO APPROVED
DRAIN
BEST PRACTICES
The following best practices are recommended to ensure
better condensate removal:
S Main and overflow drain lines should NOT be smaller
than both drain connections at drain pan.
S Overflow drain line should run to an area where
homeowner will notice drainage.
S It is recommended that the overflow drain line be
vented and a trap installed. Refer to local codes.
Inspecting and Replacing Filters
IMPORTANT
Filter access panel must be in place during unit
operation. Excessive warm air entering the unit may
result in water blow−off problems.
506294−01
Filters may be duct−mounted or installed in the cabinet. A
filter is installed at the factory. Note that filter access door
fits over access panel. Air will leak if the access panel is
placed over the filter door.
Filters should be inspected monthly and must be cleaned
or replaced when dirty to assure proper air handler
operation.
Reusable filters supplied with some units can be washed
with water and mild detergent. Some units are equipped
with standard throw−away type filters which should be
replaced when dirty.
To remove filter:
1. Loosen the thumbscrews holding the filter panel in
place.
2. Insert new filter and replace panel.
Page 8
Table 3. Filter Dimensions
CBX27UH Filter Size − In. (mm)
−018, −024, −030, and −036
−042, −048, and −060 20 x 24 (508 x 610)
20" x 20" (508mm x
508mm)
4. For best air performance external static pressure
drop must not exceed 0.5" W.C. (1.2 kPa). Refer to
blower data tables for cfm and external static.
5. Seal around the hole when the check is complete.
Adjusting Blower Speed
Sealing the Unit
WARNING
There must be an airtight seal between the bottom of the
air handler and the return air plenum. Use fiberglass
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 air handler or any gas−fueled appliance
(i.e., water heater), or carbon monoxide−producing
device (i.e., wood fireplace) is installed.
Seal the unit so that warm air is not allowed into the
cabinet. Warm air introduces moisture, which results in
water blow−off problems. This is especially important when
the unit is installed in an unconditioned area.
Make sure the liquid line and suction line entry points are
sealed with either the provided flexible elastomeric thermal
insulation, or field provided material (e.g. Armaflex,
Permagum or equivalent). Any of the previously mention
materials may be used to seal around the main and
auxiliary drains, and around open areas of electrical inlets.
Measuring Static Pressure
1. Measure tap locations as shown in figure 9.
MANOMETER
SUPPLY
UNIT SHOWN IN
HORIZONTAL DISCHARGE LEFT POSITION
Figure 9. Static Pressure Test
2. Punch a 1/4" (6mm) diameter hole in supply and return
air plenums. Insert manometer hose flush with inside
edge of hole or insulation. Seal around the hose with
permagum. Connect the zero end of the manometer
to the discharge (supply) side of the system. On
ducted systems, connect the other end of manometer
to the return duct as above. For systems with
non−ducted returns, leave the other end of the
manometer open to the atmosphere.
3. With only the blower motor running and the
evaporator coil dry, observe the manometer
reading. Adjust blower motor speed to deliver the air
desired according to the job requirements.
RETURN
MOTOR SPEED TAPS
NOTE − Motor is programmed for a 45-second delay off on
all speed taps except TAP #1 (continuous fan speed).
Table 4 lists the recommended factory blower speed tap
selections for CBX27UH series units.
Table 4. Recommended Blower Speed Tap Selection
Operation CBX27UH Outdoor Unit Ta p
Cooling
ALL SIZES
Heating*
* Minimum setting for heat
Condensing unit 3
Heat pump 3
Condensing unit with electric heat only
Heat pump with electric heat 4
These settings are for nominal tonnage match−ups with the
CBX27UH units. When matched with other sizes, it is
recommended that the CFM be adjusted to approximately
400 CFM per ton.
To change blower motor speed tap remove the speed tap
from Y2 on the terminal strip and insert the desired speed
tap. See table 6 on page 10 for the desired CFM setting.
IMPORTANT
The high-efficiency programmable motor (e.g. X13)
features programmed electronic braking. The integral
control brakes the motor near the end of the supply
blower operation, allowing the motor to maintain a more
controlled ramping shut−down.
Table 5. Motor Speed Taps
Tap Operation Remarks
Continuous fan speed is energized (24
volt input to G) when either G or Y1
has a 24 volt signal (24 volt input from
Y1 passes through the room
thermostat’s Fan Automatic contacts
to the G terminal).
CFM set at 1/2 ton less than nominal
of unit (e.g. 3-ton set at 1000 CFM).
CFM set at 400 cfm per nominal ton at
ARI minimum static allowed, as follows:
1.5 to 2.0 ton − 0.10
2.5 to 3.5 ton − 0.15
4 to 5 ton − 0.20
CFM set at 400 cfm per nominal ton at
.4 static. Energized when electric heat
element has a call for heat.
CFM set at 400 cfm per nominal ton at
.8 static.
Page 9
Continuous or low
speed fan (for
1
two−speed heat
pumps or A/C units)
Low-speed
operation on high
2
static system
Cooling speed
3
setting
Heat pump with
4
electric heat
High static
5
applications
4
CBX27UH SERIES
Table 6. CB(X)27UH Air Handler Performance
[in. w.g. − external static pressure expressed in inches water gauge; cfm − cubic feet/minute; W − watts]
Air Volume with Motor Watts at 208V Air Volume with Motor Watts at 230V
Size
.in.
w.g.
.00 815 80 810 77 835 86 855 89 1010 137 820 82 815 77 835 84 850 91 1010 140
.10 720 71 700 68 735 76 790 89 980 142 710 71 715 71 735 77 795 89 975 144
.20 580 59 560 58 665 76 755 99 950 153 570 59 580 60 660 77 755 99 950 154
.30 500 63 450 55 610 78 710 101 905 157 505 64 440 58 615 80 715 102 910 160
.40 400 65 350 59 580 87 685 111 870 166 415 67 355 60 575 89 680 112 875 170
018
.50 365 74 290 60 505 96 640 11 4 835 176 355 77 300 64 510 99 630 11 8 850 179
.60 315 75 280 68 445 100 580 124 800 179 320 77 270 71 450 102 575 129 805 183
.70 N/A N/A 210 71 390 102 515 128 755 187 N/A N/A 220 72 395 106 525 137 780 192
.80 N/A N/A 170 71 355 109 470 136 710 194 N/A N/A 175 76 365 11 2 485 144 725 200
.00 885 89 885 89 930 97 1035 130 1185 184 890 91 895 90 920 99 1040 130 1190 189
.10 755 77 760 77 850 98 995 139 1140 193 785 82 770 78 855 100 1000 142 1145 200
.20 665 73 670 72 820 106 970 148 1100 203 675 76 670 76 820 111 960 152 111 0 207
.30 605 77 600 77 775 112 920 154 1070 213 605 80 605 80 780 114 930 156 1085 219
.40 560 84 515 88 725 121 885 165 1025 219 570 88 555 88 745 123 890 166 1035 225
024
.50 445 95 445 95 675 124 835 171 1000 228 465 99 465 99 670 131 850 172 1010 235
.60 400 98 395 96 570 137 810 179 960 232 405 101 405 101 595 142 815 183 975 246
.70 N/A N/A 345 101 520 143 705 193 920 242 N/A N/A 350 106 530 151 710 197 935 248
.80 N/A N/A 320 106 460 148 625 201 835 254 N/A N/A 330 11 2 485 155 660 207 895 260
.00 1130 128 1175 142 1230 158 1270 177 1345 208 1145 130 1180 142 1235 161 1280 179 1365 212
.10 1045 11 8 1065 126 1140 151 1240 183 1345 219 1030 11 8 1085 130 1155 154 1245 183 1345 223
.20 910 103 950 11 3 1105 160 1205 193 1305 231 915 105 955 11 6 1120 164 1205 195 1310 237
.30 730 89 870 11 7 1050 169 1165 202 1250 238 755 91 885 11 8 1060 171 1170 207 1265 242
.40 605 93 825 120 1020 176 1115 209 1205 248 655 92 830 124 1030 180 1125 213 1230 254
030
.50 540 101 725 136 980 181 1085 218 1180 257 550 102 745 136 985 184 1090 223 1195 265
.60 470 106 670 145 930 191 1035 224 1140 262 475 107 670 149 945 195 1050 230 1145 270
.70 N/A N/A 605 154 835 207 995 235 1105 273 N/A N/A 620 159 860 213 1005 242 1110 280
.80 N/A N/A 545 159 785 217 950 245 1055 284 N/A N/A 560 163 805 223 915 258 1050 295
.00 1185 136 1225 149 1320 184 1430 234 1545 293 1180 139 1230 152 1330 191 1440 238 1555 299
.10 1070 125 1125 137 1280 196 1395 244 1515 303 1085 129 1125 141 1195 201 1405 251 1520 313
.20 960 113 1010 130 1240 201 1360 255 1475 314 955 114 1025 132 1260 213 1365 264 1485 325
.30 815 101 970 136 1195 214 1310 265 1430 322 805 105 975 142 1210 219 1330 275 1445 337
.40 750 106 915 148 1155 225 1275 273 1385 334 770 114 930 153 1170 231 1285 283 1405 345
036
.50 670 119 870 153 111 0 231 1240 284 1345 345 670 128 870 159 1120 243 1250 295 1365 357
.60 605 130 825 163 1160 242 1190 290 1315 355 605 134 810 173 1080 249 1210 307 1330 367
.70 555 137 725 177 1125 251 1145 301 1270 359 565 142 725 185 1040 260 1160 313 1285 378
.80 515 142 670 282 970 262 1100 312 1225 369 525 146 675 195 980 276 1120 324 1245 391
.00 1475 198 1530 218 1610 251 1705 295 1805 349 1475 200 1530 222 1615 254 1705 300 1815 350
.10 1370 183 1420 207 1545 251 1660 307 1780 364 1360 184 1435 207 1545 255 1665 310 1775 368
.20 1255 172 1305 189 1515 266 1635 322 1750 378 1245 172 1305 190 1515 269 1630 326 1750 384
.30 1090 153 1250 200 1470 278 1600 336 1705 390 1090 155 1255 203 1470 278 1605 343 1715 395
.40 1010 164 1190 210 1430 295 1560 346 1685 407 1020 165 1200 213 1420 300 1565 351 1680 408
042
.50 955 177 1145 225 1385 310 1510 373 1640 428 955 178 1150 229 1385 314 1520 373 1650 430
.60 885 183 1090 242 1330 319 1475 384 1590 443 915 183 1095 243 1330 324 1480 390 1595 453
.70 N/A N/A 1005 248 1255 341 1430 401 1565 457 N/A N/A 1000 254 1265 344 1440 408 1565 468
.80 N/A N/A 990 260 1200 355 1365 419 1510 473 N/A N/A 1000 255 1200 362 1375 429 1515 481
.00 1440 200 1515 233 1670 304 1690 313 1850 413 1440 202 1525 237 1680 309 1700 319 1860 422
.10 1370 188 1455 224 1650 318 1670 329 1825 421 1370 189 1465 224 1665 324 1685 331 1840 431
.20 1260 173 1425 231 1635 327 1660 337 1825 436 1255 177 1425 235 1650 331 1675 342 1840 443
.30 1120 166 1380 242 1605 343 1630 351 1800 447 1125 167 1380 243 1625 349 1645 358 1815 461
.40 1055 172 1335 260 1565 352 1595 367 1770 462 1055 177 1335 262 1585 358 1605 373 1780 471
048
.50 960 190 1295 273 1530 372 1555 377 1735 479 970 194 1290 278 1535 378 1570 385 1745 490
.60 895 195 1230 285 1490 389 1510 401 1695 489 890 201 1230 296 1500 396 1525 408 1720 506
.70 N/A N/A 1145 304 1445 407 1470 418 1650 513 N/A N/A 1140 308 1455 415 1490 425 1665 533
.80 N/A N/A 1095 317 1385 416 1430 432 1605 530 N/A N/A 1075 325 1405 435 1430 445 1630 551
.00 1490 207 1765 331 1970 455 2010 494 2365 799 1505 212 1775 337 1980 461 2025 497 2365 822
.10 1395 194 1740 344 1930 466 1985 507 2328 810 1400 198 1745 352 1950 475 1990 514 2345 839
.20 1320 192 1700 354 1900 480 1955 522 2300 827 1325 196 1705 361 1910 490 1965 532 2310 850
.30 1275 206 1670 367 1875 487 1915 531 2265 842 1270 211 1675 374 1890 507 1930 540 2285 863
.40 1220 214 1620 378 1825 504 1890 544 2235 850 1230 224 1635 390 1840 516 1905 556 2255 882
060
.50 1170 226 1575 395 1795 519 1850 555 2205 861 1185 231 1590 402 1815 532 1875 573 2225 891
.60 1135 241 1535 409 1750 529 1810 569 2175 872 1140 239 1545 419 1785 550 1825 585 2190 908
.70 N/A N/A 1490 417 1720 543 1775 585 2135 885 N/A N/A 1510 426 1735 562 1795 602 2155 922
.80 N/A N/A 1470 429 1685 557 1730 592 2085 893 N/A N/A 1480 442 1700 574 1760 619 2120 940
Tap 1 Tap 2 Tap 3 Tap 4 Tap 5 Tap 1 Tap 2 Tap 3 Tap 4 Tap 5
cfm W cfm W cfm W cfm W cfm W cfm W cfm W cfm W cfm W cfm W
506294−01
Page 10
Making Electrical Connections
WARNING
Run 24V Class II wiring only through specified low voltage opening. Run line voltage wiring only through specified high voltage opening. Do not combine voltage in one
opening.
CAUTION
USE COPPER CONDUCTORS ONLY.
This unit is provided with knock-outs for conduit. Refer to
figure 12 on page 13 for unit wiring diagram, which includes
all field wiring. Separate openings have been provided for
24V low voltage and line voltage. Refer to the dimension
illustration on page 2 or 3 for specific location.
Wiring must conform to the current National Electric Code
ANSI/NFPA No. 70, or Canadian Electric Code Part I, CSA
Standard C22.1, and local building codes. Refer to
following wiring diagrams. See unit nameplate for
minimum circuit ampacity and maximum overcurrent
protection size.
2. Ground unit at unit disconnect switch or to an earth
ground.
NOTE Connect conduit to the unit using a proper
conduit fitting. Units are approved for use only with
copper conductors. A complete unit wiring diagram is
located on the back side of the unit’s access panel.
3. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit.
NOTE For proper voltages, select thermostat wire
gauge per the following chart:
Table 7. Run Length (Class II Rated Wiring)
Wire Run Length AWG # Insulation/Core Types
Less than 100’ (30m) 18
More than 100’ (30m) 16
Install room thermostat (ordered separately) on an inside wall
approximately in the center of the conditioned area and 5 feet (1.5m)
from the floor. It should not be installed on an outside wall or where it
can be affected by sunlight or drafts.
THERMOSTAT
Color−coded, temperature
rating 95ºF (35ºC) minimum,
solid core.
Select the proper supply circuit conductors in
accordance with tables 310−16 and 310−17 in the
National Electric Code, ANSI/NFPA No. 70 or tables 1
through 4 in the Canadian Electric Code, Part I, CSA
Standard C22.1.
The motor speed is set by the speed tap connection to the
low voltage terminal strip in the control section. The speed
can be increased by swapping wires as shown in figure 10.
WIRING CONNECTIONS
1. Install line voltage power supply to unit from a properly
circuit breaker.
5 FEET
(1.5M)
NOTE 24VAC, Class II circuit
connections are made in the control panel.
NOTE Units are approved for use only with copper conductors.
Ground unit at disconnect switch or to an earth ground.
Page 11
CBX27UH SERIES
MOTOR SPEED
TAPS 1 AND 2
Figure 10. Motor Speed Taps (208/230V, Single Phase)
TO INCREASE MOTOR
SPEED, DISCONNECT GRN
WIRE AND CONNECT YEL
WIRE.
MOTOR SPEED
TAPS 1 AND 2
Figure 11. Motor Speed Taps 460V, 3−Phase, 60Hz Single Phase (−036, −048 and −060 only)
506294−01
Page 12
TO INCREASE MOTOR
SPEED, DISCONNECT GRN
WIRE AND CONNECT YEL
WIRE.
Figure 12. Typical System Wiring Diagram (208/230V, Single and Three Phase)
Page 13
CBX27UH SERIES
Figure 13. Typical System Wiring Diagram 460V, Single and Three Phase (−036, −048 and −060 only)
506294−01
Page 14
Repairing or Replacing Cabinet Insulation
IMPORTANT
DAMAGED INSULATION MUST BE REPAIRED OR
REPLACED before the unit is put back into operation.
Insulation loses its insulating value when wet, damaged,
separated or torn.
Matt- or foil−faced insulation is installed in indoor
equipment to provide a barrier between outside air
conditions (surrounding ambient temperature and
humidity) and the varying conditions inside the unit. If the
insulation barrier is damaged (wet, ripped, torn or
separated from the cabinet walls), the surrounding
ambient air will affect the inside surface temperature of the
cabinet. The temperature/humidity difference between the
inside and outside of the cabinet can cause condensation
on the inside or outside of the cabinet which leads to sheet
metal corrosion and subsequently, component failure.
REPAIRING DAMAGED INSULATION
Areas of condensation on the cabinet surface are an
indication that the insulation is in need of repair.
If the insulation in need of repair is otherwise in good
condition, the insulation should be cut in an X pattern,
peeled open, glued with an appropriate all−purpose glue
and placed back against the cabinet surface, being careful
to not overly compress the insulation so the insulation can
retain its original thickness. If such repair is not possible,
replace the insulation. If using foil-faced insulation, any
cut, tear, or separations in the insulation surface must be
taped with a similar foil−faced tape.
GLUE − Make sure there is
full coverage of glue on the
metal or insulation so there
are no areas where air
pockets may form which
can lead to sweating.
1. CUT INSULATION IN X PATTERN
2. APPLY GLUE
3. PRESS GLUED TABS AGAINST CABINET
Figure 14. Repairing Insulation
WARNING
Electric Shock Hazard.
Can cause injury or death.
Foil-faced insulation has conductive characteristics
similar to metal. Be sure there are no electrical
connections within a ½" of the insulation. If the foil-faced
insulation comes in contact with electrical voltage, the foil
could provide a path for current to pass through to the
outer metal cabinet. While the current produced may not
be enough to trip existing electrical safety devices (e.g.
fuses or circuit breakers), the current can be enough to
cause an electric shock hazard that could cause
personal injury or death.
Page 15
CBX27UH SERIES
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