Lennox ML180UHE Manual

GAS FURNACES
ML180UHE
MERIT® SERIES
Upow / Horizontal - High Efciency Blower Motor
Bulletin No. 210613
June 2011
ENGINEERING DATA
AFUE - 80%
Input - 44,000 to 132,000 Btuh
Nominal Add-on Cooling - 1.5 to 5 Tons
ML 1 80 UH 070 X E 36 B
Unit Type
ML = Merit Series®
Stages
1 = Single-Stage
Nominal Gas Heat Input
045 = 44,000 Btuh
070 = 66,000 Btuh
090 = 88,000 Btuh
110 = 110,000 Btuh
135 = 132,000 Btuh
Blower
E = High Efciency Constant Torque Blower Motor
Nominal Add-On Cooling Capacity
36 = 1.5-3 tons
48 = 2.5-4 tons
60 = 3-5 tons
Conguration
UH = Upow/Horizontal
MODEL NUMBER IDENTIFICATION
1 Indoor coils with the same letter designation will physically match the furnace.
1 Cabinet Width
A = 14-1/2 in.
B = 17-1/2 in.
C = 21 in.
D = 24-1/2 in.
AFUE
80 = 80%
Low NOx = Units meet California
Nitrogen Oxides standards

ML180UHE / Page 2
WARRANTY
Duralok™ Aluminized Steel Heat Exchanger
- Limited twenty year warranty in residential
applications, ten years in non-residential applications.
All other covered components - Limited ve year
warranty in residential applications, one year in non-
residential applications.
Refer to Lennox Equipment Limited Warranty certicate
included with equipment for details.
APPROVALS
Units are Certied by AHRI.
Units tested and rated according to US DOE test
procedures and FTC labeling regulations.
“X” models approved by the California Energy
Commission and meet California Seasonal Efciency
requirements and California Nitrogen Oxides (NOx)
Standards.
ISO 9001 Registered Manufacturing Quality System.
Blower data from unit tests conducted in Lennox
Laboratory air test chamber.
APPLICATIONS
Input capacities of 44,000, 66,000, 88,000, 110,000 and
132,000 Btuh.
Energy efciency (AFUE) of 80%.
Compact cabinet for upow, horizontal-left or horizontal-
right applications.
Utility room, alcove, closet, crawl space, basement or
attic installation.
Lennox add-on indoor coils, high-efciency air cleaners
and humidiers can easily be added to furnace.
Shipped factory assembled with all controls installed
and wired.
Ready for installation in upow or horizontal right-hand
position without any modications. Horizontal left-hand
position requires repositioning of pressure switch.
Removable bottom seal panel shipped in place for side
return air is easily removed for bottom/end return air
applications.
Each unit factory test operated to ensure proper
operation.
FEATURES
Contents
Blower Data . . . . . . . . . . . . . . . . . . . . . . 13
Dimensions - Furnace/Coil Combined Dimensions . . 12
Dimensions - Horizontal Position . . . . . . . . . . . 10
Dimensions - Upow Position. . . . . . . . . . . . . 9
Features. . . . . . . . . . . . . . . . . . . . . . . . 2
Gas Heat Accessories . . . . . . . . . . . . . . . . 8
High Altitude Derate. . . . . . . . . . . . . . . . . . 8
Installation Clearances . . . . . . . . . . . . . . . . 7
Model Number Identication . . . . . . . . . . . . . 1
Optional Accessories . . . . . . . . . . . . . . . . . 8
Optional Accessory Dimensions . . . . . . . . . . . 11
Specications . . . . . . . . . . . . . . . . . . . . . 7
B
C
H
D
E
G
F
I
J
K
NOTE - ML180UHE FURNACES ARE NOT
AVAILABLE IN CANADA!
L

ML180UHE / Page 3
HEATING SYSTEM
Lennox Duralok™ Heat Exchanger Assembly
Heavy gauge aluminized steel heat exchanger.
Crimped seam clamshell type design.
Designed for normal expansion and contraction.
Minimum resistance to
air ow.
Heat exchanger has
been laboratory life
cycle tested in excess of
industry standards.
Compact size of heat
exchanger permits low
overall design of furnace
cabinet.
Inshot Burners
Aluminized steel inshot burners provide efcient,
trouble-free operation.
Burner venturi mixes air and gas in correct proportion
for proper combustion.
Burner assembly is removable from the unit as a single
component for ease of service.
SureLight® Hot Surface Ignitor
Tough, reliable, long-life, trouble-free performance.
Silicon nitride ignitor.
Cemented to steatite block for protection against current
leakage.
Ignition leads are constructed of nickel plated copper
and are enclosed in high temperature Teon® insulation
for dependable operation.
Gas Control Valve
24 volt redundant combination gas control valve
combines manual shut off switch (On-Off), automatic
electric valve (dual) and gas pressure regulation into a
compact combination control.
Combustion Air Inducer
Shaded pole heavy duty blower prepurges heat
exchanger and safely vents ue products.
Pressure switch proves blower operation before
allowing gas valve to open.
Operates only during heating cycle.
Direct access allows inducer assembly to be rotated
90° clockwise or counterclockwise to facilitate easy vent
attachment from either side of the cabinet in upow
applications and from the top in horizontal applications.
A
B
C
D
E
F
Flame Rollout Switches (2)
Manual reset switches are factory installed on burner
box.
Switches provides protection from abnormal operating
conditions.
Limit Controls
Automatic reset, primary and secondary limits are
accurately located.
Primary limit factory installed on vestibule panel on
all units, secondary limit factory installed on blower
housing.
OPTIONS
High Altitude Pressure Switch Kit
Required on most units for proper unit operation at
altitudes from 4,501 to 7500 ft.
Natural Gas to LPG/Propane Conversion Kit
Required for eld changeover from natural gas to LPG/
Propane.
LPG/Propane to Natural Gas Conversion Kit
Required for eld changeover from LPG/Propane to
natural gas.
Vent Adaptor (Upow Applications Only)
Allows venting through a
masonry chimney without the
need of a ue liner.
Manual reset temperature
sensor protects against
abnormal operating conditions.
Sensor wiring may be routed
from either side of adaptor.
Minimum winter design
temperatures:
−10°F when used with interior masonry chimneys.
+5°F when used with exterior masonry chimneys.
Refer to Winter Design Temperatures Map on page 6
for application information. Also refer to the installation
instructions for detailed information.
BLOWER
Direct drive blower.
Statically and dynamically balanced.
Resiliently mounted.
Blower assembly easily removed for servicing.
High Efciency Constant Torque Blower Motor
ECM (Electronically Commutated Motor) motor.
Motor is programmed to provide constant torque at each
of the selectable speeds.
Motor is controlled by the Integrated Furnace Control.
Blower speeds are easily changed on the integrated
furnace control. See blower performance tables.
G
7 in.
(178 mm)
6 in.
(152 mm)
H
FEATURES

ML180UHE / Page 4
CONTROLS
SureLight® Integrated Furnace Control
Control contains all necessary controls and relays to
operate furnace.
Combustion air inducer is operated by the integrated
furnace control. Prior to ignition, a pre-purge cycle
for 15 seconds is initiated. After the main burners are
turned off, a post-purge cycle for 5 seconds is run.
Flame sensor assures safe and reliable operation.
Should loss of ame occur the integrated furnace
control will initiate 4 re-attempts at ignition before
locking out unit operation for 60 minutes.
Watchguard type circuit automatically resets ignition
controls after one hour of continuous thermostat demand
after unit lockout, eliminating nuisance calls for service.
Fan control consists of adjustable blower timed-off delay
(60, 90, 120, 180 seconds - factory setting 90 seconds)
and xed blower timed-on delay (30 seconds - heating,
2 seconds - cooling).
For air-conditioning applications, blower is automatically
energized on thermostat demand for cooling. Control
has low speed continuous blower speed setting for
humidier or air cleaner operation.
Two accessory terminals furnished for additional
power supply requirements for 120 volt (less than 1
amp) power humidiers and powered air cleaners.
One additional terminal is furnished for power supply
requirements for 24V (less than 0.5 amp) low voltage
accessories.
Ignition control has single red LED to indicate status
and as an aid in troubleshooting.
Last ve codes are stored in non-volatile memory
(accessible by recall button on control) for servicing.
24 Volt Transformer
Furnished and factory installed on outside of control
box. 40VA transformer has fuse wired in series.
Field Wiring Make-up Box
Furnished for line voltage wiring.
Factory installed internally on left side of furnace.
Box may be installed on right side of furnace.
I
FEATURES
OPTIONS
Thermostat
Thermostat (programmable/non-programmable) is not
furnished with unit.
See Thermostat bulletins in Controls Section and
Lennox Price Book for selection.
FILTER (NOT FURNISHED)
Filter and provisions for external mounting must be eld
provided.
OPTIONS
Air Filter and Rack Kit for Horizontal Return Air
(End) Applications
Washable or vacuum cleanable polyurethane frame
type lter and external end return air rack available for
eld installation.
Rack has lter door for easy lter servicing.
Flanges on rack allow easy duct connection.
See dimension drawing.
Air Filter and Rack Kit for Upow Side Return Air
Applications - Not for use with Return Air Base
Washable or vacuum cleanable polyurethane frame
type lter and external side return air rack available for
eld installation.
Available in single and ten pack kits.
Rack has lter door for easy lter servicing.
Flanges on rack allow easy duct connection.
Field installs on either side of unit cabinet. See
dimension drawing.

ML180UHE / Page 5
FEATURES
CABINET
Low-prole, narrow width cabinet allows easy
installation.
Heavy-gauge, cold rolled steel construction.
Pre-painted cabinet nish.
Flue outlet on top of cabinet for upow applications,
can be relocated to either side of cabinet for horizontal
applications.
Flanges provided on supply air opening for ease of
plenum connection or alignment with indoor coil.
Insulated cabinet with foil faced insulation on sides and
back of heating compartment.
Complete service access.
Safety interlock switch automatically shuts off power
to unit when blower compartment access panel is
removed.
Gas piping and electrical inlets are provided in both
sides of cabinet.
Return Air Entry:
For bottom/end return-air entry for upow/horizontal
applications, remove furnished bottom seal panel from
cabinet.
For side return-air entry (upow applications only),
corners are marked on either side of cabinet for return
air cut-outs.
See dimension drawings.
NOTE - 60C and 60D size units that require air
volumes over 1800 cfm must have one of the
following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. cleanable air lter. Required to
maintain proper air velocity.
2. Single side return air with Optional Return Air Base
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air.
See Blower Performance Tables for additional
information.
Coil Match-up
All furnaces exactly match C33 and CX34 cased upow
indoor coils and CH33 horizontal indoor coils with
same letter designation in model number. No adaptor
required. Engaging holes furnished on cabinet for
alignment.
C33 uncased coils match furnaces without any
overhang but require an optional adaptor base or eld
fabricated transition to match furnace opening. See C33
coil bulletin for additional information.
J
K
L
OPTIONS
Horizontal Suspension Kit
Provides suspension of unit and coil in horizontal
applications.
Allows complete service access.
Consists of corner mounted hanging brackets with
vibration isolators, return air end support rail and
hardware for assembly.
Metal hanging straps must be eld provided.
Return Air Base
A eld fabricated transition or Return Air Base is
required when using an IAQ product higher than 14-
3/16 in. installed next to the unit and serviced from the
front. IAQ products higher than 20 in. require a eld
fabricated transition.
Base must be used for 60C and 60D models with air
volumes over 1800 cfm in upow applications when
only one side return is required.
Cabinet is shipped at for easy eld assembly and is
pre-painted steel to match the furnace.
See Dimension Drawing.

ML180UHE / Page 6
99% WINTER DESIGN TEMPERATURES FOR THE CONTIGUOUS UNITED STATES
This map is a necessarily generalized guide to temperatures in the contiguous Unites States. Temperatures shown for
areas such as mountainous regions and large urban centers may not be accurate. The data used to develop this map
was taken from the 1993 ASHRAE Fundamentals Handbook (Chapter 24, Table 1: Climate Conditions for the United
States).
Reprinted with permission from NFPA 54: National Fuel Gas Code 1999, National Fire Protection Association, Quincy,
MA 02269. This reprinted material is not the complete and ofcial position of the National Fire Protection Association on
the referenced subject, which is represented only by the standard in its entirety.
−10
oF
−10
o
F
5oF
17oF
27oF
37oF
37oF
27oF
17oF
5oF
−10
oF

ML180UHE / Page 7
SPECIFICATIONS
Gas
Heating
Performance
Model No. ML180UH045E36A ML180UH070E36B ML180UH090E48B
Model No. - Low Nox ML180UH045XE36A ML180UH070XE36B ML180UH090XE48B
1 AFUE 80% 80% 80%
Input - Btuh 44,000 66,000 88,000
Output - Btuh 36,000 53,000 72,000
Temperature rise range - °F 15 - 45 40 - 70 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
High Static - in. w.g. 0.50 0.50 0.50
Connections
in.
Flue connection - in. round 4 4 4
Gas pipe size IPS 1/2 1/2 1/2
Indoor
Blower
Wheel nom. dia. x width - in. 10 x 8 10 x 10 10 x 10
Motor output - hp 1/2 1/2 3/4
Tons of add-on cooling 1.5 - 3 1.5 - 3 2.5 - 4
Air Volume Range - cfm 350 - 1380 395 - 1415 750 - 1785
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 6.8 6.8 8.4
Maximum overcurrent protection 12 12 12
Shipping Data lbs. - 1 package 111 127 142
SPECIFICATIONS
Gas
Heating
Performance
Model No. ML180UH090E60C ML180UH110E60C ML180UH135E60D
Model No. - Low Nox - - - ML180UH110XE60C - - -
1 AFUE 80% 80% 80%
Input - Btuh 88,000 110,000 132,000
Output - Btuh 72,000 90,000 107,000
Temperature rise range - °F 30 - 60 35 - 65 30 - 60
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
High Static - in. w.g. 0.50 0.50 0.50
Connections
in.
Flue connection - in. round 4 4 4
Gas pipe size IPS 1/2 1/2 1/2
Indoor
Blower
Wheel nom. dia. x width - in. 11-1/2 x 10 11-1/2 x 10 11 x 11
Motor output - hp 1 1 1
Tons of add-on cooling 3 - 5 3 - 5 3.5 - 5
Air Volume Range - cfm 990 - 2290 920 - 2315 1140 - 2495
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 10.9 10.9 10.9
Maximum overcurrent protection 12 12 12
Shipping Data lbs. - 1 package 152 160 178
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
1 Annual Fuel Utilization Efciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.
UPFLOW POSITION
Vent Type Type B1 Type C
Sides 0 (0) 1 0 (0)
Rear 0 (0) 0 (0)
Top 1 (25) 1 (25)
Front 2-1/4 (57) 2-1/4 (57)
Front (service/alcove) 24 (610) 24 (610)
Floor Combustible Combustible
Flue 1 (25) 6 (152)
NOTE − Air for combustion must conform to the methods outlined in the National
Fuel Gas Code (NFPA 54/ANSI-Z223.1).
NOTE − In the U.S. ue sizing must conform to the methods outlined in the
current National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or applicable
provisions of local building codes.
1 Left side requires 4 in. if single wall vent is used on 14-1/2 in. cabinets, 2 in. on
17-1/2 in. cabinets.
INSTALLATION CLEARANCES - INCHES (MM)
HORIZONTAL POSITION
Vent Type Type B1 Type C
End 1 2 1 2
Rear 0 (0) 0 (0)
Top 1 0 (0) 1 0 (0)
Front 2-1/4 (57) 2-1/4 (57)
Front (service) 24 (610) 24 (610)
Floor Combustible Combustible
Flue 1 (25) 6 (152)
NOTE − Air for combustion must conform to the methods outlined in the National
Fuel Gas Code (NFPA 54/ANSI-Z223.1).
NOTE − In the U.S. ue sizing must conform to the methods outlined in the
current National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or applicable
provisions of local building codes.
1 Line contact installation permissible between jacket top or sides and building
joists.

ML180UHE / Page 8
OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA
“A” Width
Models
“B” Width
Models
“C” Width
Models
“D” Width
Models
CABINET ACCESSORIES
Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 51W10
Return Air Base - Upow only 65W75 50W98 50W99 51W00
FILTERS
1 Air Filter and Rack Kit Horizontal (end) 87L95 87L96 87L97 87L98
Size of lter - in. 14 x 25 x 1 18 x 25 x 1 20 x 25 x 1 25 x 25 x 1
Side Return Single 44J22 44J22 44J22 44J22
Ten Pack 66K63 66K63 66K63 66K63
Size of lter - in. 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1
VENTING
Vent Adaptor − 6 in. conn. size upow applications only 18M79 18M79 18M79 18M79
1 Cleanable polyurethane, frame-type lter.
GAS HEAT ACCESSORIES
Input
High Altitude
Pressure Switch Kit
Natural Gas to
LPG/Propane Kit
LPG/Propane
to Natural Gas Kit
Natural Gas
High Altitude
Orice Kit
0 - 4500 ft. 4501 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 7501 - 10,000 ft.
045 No Change 80W52 80W51 70W89 76W15 73W81 73W37
070 No Change 80W52 80W51 70W89 76W15 73W81 73W37
090 No Change 80W52 80W51 70W89 76W15 73W81 73W37
110 No Change 80W52 80W52 70W89 76W15 73W81 73W37
135 No Change 80W52 80W51 70W89 76W15 73W81 73W37
HIGH ALTITUDE DERATE
NOTE - Units may be installed at altitudes up to 2000 ft. above sea level without any modications.
At altitudes above 2000 ft. units must be derated to match information in the shaded areas shown below.
NOTE - This is the only permissible derate for these units.
Input
Gas Manifold Pressure (Outlet) in. w.g. Line Pressure - in. w.g.
0 - 2000 Feet 2001 - 4500 Feet 4501 - 7500 Feet 7501 - 10,000 ft. Minimum
Maximum
Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
1 Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
045 3.5 10 3.2 10 3 10 3.5 10 4.5 11 13
070 3.5 10 3.2 10 2.8 10 3.5 10 4.5 11 13
090 3.5 10 3.2 10 2.7 9.6 3.5 10 4.5 11 13
110 3.5 10 3.5 10 3 9.6 3.5 10 4.5 11 13
135 3.5 10 3.5 10 2.9 9.6 3.5 10 4.5 11 13
1 Natural Gas High Altitude Orice Kit required.

ML180UHE / Page 9
DIMENSIONS - INCHES (MM) - UPFLOW POSITION
Model No. A B C D
in. mm in. mm in. mm in. mm
ML180UH045E36A 14-1/2 368 13-3/8 340 13 330 4-3/4 121
ML180UH070E36B
ML180UH090E48B 17-1/2 446 16-3/8 416 16 406 6-1/4 159
ML180UH090E60C
ML180UH110E60C 21 533 19-7/8 504 19-1/2 495 8 203
ML180UH135E60D 24-1/2 622 23-3/8 546 23 584 9-3/4 248
23
(584)
(19)
3/4
(19)
1 Bottom Return
Air Opening
GAS PIPING INLET
(Either Side)
Side Return
Air Opening
(Either Side)
1
Bottom Return
Air Opening
FLUE OUTLET
(Top)
ELECTRICAL INLET
(Either Side)
SUPPLY AIR
OPENING
FRONT VIEW SIDE VIEW
TOP VIEW
A
B9/16 (14)
C
D
3/4
27-3/4
(705)
19-7/16
(494)
23-1/2
(597)
1-1/2
(38)
9-1/8 (232) Right
8-5/8 (219) Left
5-3/8 (137) Right
1-9/16 (40) Left
33
(838)
3-1/8 (79)
1-15/16 (49)
14
(356)
9/16
(14)
3 (76) Right
6-3/4 (171) Left
2
FLUE OUTLET
(Either Side)
3 OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
16
(406)
14-3/4
(375)
3 OPTIONAL
EXTERNAL
SIDE RETURN
AIR FILTER KIT
(Either Side)
2
Flue outlet may be horizontal but furnace must be
vented vertically
3
Optional External Side Return Air Filter Kit is not for use
with the optional Return Air Base.
1 NOTE - 60C and 60D size units that require air volumes
over 1800 cfm must have one of the following:
1. Single side return air with transition, to accommodate
20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air
filter. Required to maintain proper air velocity.
2. Single side return air with optional Return Air Base
3. Bottom return air.
4. Return air from both sides.
5. Bottom and one side return air.
See Blower Performance Tables for additional information.
3-1/4 (83)
5/8
(16)
1
3-1/4
(83)
23-3/4
(603)
25
(635)
3/4(19)
Front Panel
ELECTRICAL
INLET (Either Side)
(Either Side)

ML180UHE / Page 10
DIMENSIONS - INCHES (MM) - HORIZONTAL POSITION
27-3/4
(705)
27-3/4
(705)
D
A
TOP VIEW
33
(838)
27-3/4
(705)
A
(79)
6-3/4
GAS PIPING INLET
(Top or Bottom)
RETURN
AIR
OPENING
FLUE OUTLET
(Top)
ELECTRICAL INLET
(Top or Bottom)
SUPPLY
AIR
OPENING
FRONT VIEW
TOP VIEW
CA
END VIEWEND VIEW
33
(838)
27-3/4
(705)
19-7/16
(494)
9/16
(14)
B
23-1/2
(597)
4-1/4
(108)
(19)
5-3/8 (137) Top
1-9/16 (40) Bottom
9-1/8 (232) Top
8-5/8 (219) Bottom
3 (76)
(171)
3-1/8
1FLUE
OUTLET
(End)
LEFT-HAND AIR DISCHARGE
1 Flue outlet may be from end but
furnace must be vented vertically
FRONT VIEW
END VIEW END VIEW
1 FLUE OUTLET
(Top)
3 (76)
6-3/4
(171)
AIR
FLOW
GAS PIPING INLET
(Top or Bottom)
ELECTRICAL INLET
(Top or Bottom)
RIGHT-HAND AIR DISCHARGE
1 Flue outlet may be horizontal but
furnace must be vented vertically
9-1/8 (232) Bottom
8 (203) Top
5-3/8 (137) Bottom
1-5/8 (41) Top
9/16
(14) 3/4
AIR
FLOW
AIR
FLOW
19-7/16
(494) 9/16
(14)
B
9/16
(14)
D
A
1FLUE OUTLET
(End)
(79)
3-1/8
SUPPLY
AIR
OPENING
RETURN
AIR
OPENING
C
23-1/2
(597)
4-1/4
(108)
(19)
3/4
AIR
FLOW
3/4 (19)
Front Panel
3/4 (19)
Front Panel
Model No. A B C D
in. mm in. mm in. mm in. mm
ML180UH045E36A 14-1/2 368 13-3/8 340 13 330 4-3/4 121
ML180UH070E36B
ML180UH090E48B 17-1/2 446 16-3/8 416 16 406 6-1/4 159
ML180UH090E60C
ML180UH110E60C 21 533 19-7/8 504 19-1/2 495 8 203
ML180UH135E60D 24-1/2 622 23-3/8 546 23 584 9-3/4 248

ML180UHE / Page 11
OPTIONAL ACCESSORY DIMENSIONS - INCHES (MM)
1-1/4
HORIZONTAL (END) FILTER KIT
FRONT VIEW
24−3/4
(629)
AB
23−1/2
(597)
5/8
(16)
RETURN
AIR
OPENING
SIDE VIEW
AIR FLOW
AIR FILTER
(Furnished)
(32)
5/8
(16)
5/8
(16)
5/8
(16)
Optional Return Air Base
(Upflow Applications Only - For use with A, B, C and D cabinets)
NOTE- Optional Side Return Air Filter Kits are not for use with Optional Return Air Base.
1Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air
opening. The size of the opening must not extend beyond the markings on the furnace cabinet.
2To minimize pressure drop, the largest opening height possible, up to 14 in. (356 mm), is preferred.
FURNACE
FRONT
AIR FLOW
14-1/2 (368) A Width (65W75)
17-1/2 (446) B Width (50W98)
21 (533) C Width (50W99)
24-1/2 (622) D Width (51W00)
1 Unit side return air
Opening
SIDE VIEW
3-1/4
(83)
1 23 (584)
Overall
(Maximum)
(584)
23
3/4
(19)
1 22-7/16
(570)
Overall
(Maximum)
SIDE RETURN
AIR OPENINGS
(Either Side)
5-5/8
(143)
1Minimum
11 (279)
2 Maximum
14 (356)
(683)
26-7/8
7-1/4
(184)
IF BASE
IS USED
WITHOUT
IAQ CABINET,
A SINGLE
RETURN AIR
PLENUM
MUST
COVER BOTH
UNIT AND
RETURN
AIR BASE
OPENINGS
INDOOR AIR
QUALITY
CABINET
(PCO, Filter
Cabinet, etc.)
AIR BASE
OPTIONAL
RETURN
Furnace
Cabinet
Width
Catalog
Number
A B
in. mm in. mm
A 87L95 14 356 12-3/4 324
B 87L96 18 457 16-3/4 425
C 87L97 21 533 18-3/4 476
D 87L98 25 635 23-3/4 603

ML180UHE / Page 12
DIMENSIONS - INCHES (MM) - FURNACE/COIL COMBINED DIMENSIONS
UPFLOW POSITION
Model No Cased Uncased
(CX34 - cased only)
A B A B
CX34 C33 in. mm in. mm in. mm in. mm
- - - C33-18A 12-1/2 318 45-1/2 1156 9-3/4 248 42-3/4 1086
CX34-19A-6F C33-19A 16-1/2 419 49-1/2 1257 9-3/4 248 42-3/4 1086
- - - C33-24A 16-1/2 419 49-1/2 1257 14 356 47 1194
CX34-18/24A-6F
CX34-18/24B-6F
CX34-18/24C-6F
C33-24B
C33-24C
16-1/2 419 49-1/2 1257 13-7/8 352 46-7/8 1191
CX34-25A-6F C33-25A 18-1/2 470 51-1/2 1308 16-1/4 413 49-1/4 1251
CX34-25B-6F C33-25B 18-1/2 470 51-1/2 1308 15-7/8 403 48-7/8 1241
CX34-30B-6F
CX34-30C-6F
C33-30B
C33-30C 20-1/2 521 53-1/2 1359 17-3/4 451 50-3/4 1289
CX34-30A-6F C33-30A 20-1/2 521 53-1/2 1359 18 457 51 1295
CX34-31A-6F C33-31A 22-1/2 572 55-1/2 1410 21-1/4 540 54-1/4 1378
CX34-31B-6F C33-31B 22-1/2 572 55-1/2 1410 20-1/4 514 53-1/4 1353
CX34-36A-6F C33-36A 24-1/2 622 57-1/2 1461 22-1/8 562 55-1/8 1400
CX34-36B-6F C33-36B 24-1/2 622 57-1/2 1461 21-7/8 556 54-7/8 1394
CX34-36C-6F C33-36C 24-1/2 622 57-1/2 1461 21-1/4 540 54-1/4 1378
CX34-38A-6F C33-38A 24-1/2 622 57-1/2 1461 22-1/4 565 55-1/4 1403
CX34-38B-6F C33-38B 24-1/2 622 57-1/2 1461 22 559 55 1397
CX34-42B-6F C33-42B 24-1/2 622 57-1/2 1461 21-7/8 556 54-7/8 1394
CX34-43B-6F C33-43B 27-1/2 699 60-1/2 1537 26-1/4 667 59-1/4 1505
CX34-43C-6F C33-43C 27-1/2 699 60-1/2 1537 25-3/4 654 58-3/4 1492
- - - C33-44C 24-1/2 622 57-1/2 1461 21-1/2 546 54-1/2 1384
CX34-44/48B-6F C33-48B 24-1/2 622 57-1/2 1461 22-1/8 562 55-1/8 1400
CX34-44/48C-6F C33-48C 24-1/2 622 57-1/2 1461 21-1/2 546 54-1/2 1384
CX34-49C-6F C33-49C 29-1/2 749 62-1/2 1588 28-1/2 724 61-1/2 1562
CX34-50/60C-6F C33-50/60C 27-1/2 699 60-1/2 1537 24-3/4 629 57-3/4 1467
CX34-60D-6F C33-60D 25-1/2 648 58-1/2 1486 24-3/4 629 57-3/4 1467
CX34-62C-6F C33-62C 31-1/2 800 64-1/2 1638 30-5/8 778 63-5/8 1616
CX34-62D-6F C33-62D 29-1/2 749 62-1/2 1588 28-3/4 730 61-3/4 1568
HORIZONTAL POSITION
Model
Number
A B
in. mm in. mm
CH33-18A-2F 21-1/2 546 54-1/2 1384
CH33-24/30A-2F
CH33-36A-2F
CH33-36B-2F
CH33-36C-2F
CH33-42B-2F
CH33-48C-2F
CH33-60D-2F
26-1/2 673 59-1/2 1511
CH33-44/48B-2F
CH33-50/60C-2F
CH33-62D-2F 31-1/2 800 64-1/2 1638
33
(838)
A
B
33
(838)
A
B

ML180UHE / Page 13
BLOWER DATA
ML180UH045E36A PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1380 265 1155 165 995 120 975 115 945 105
0.10 1345 270 1120 175 950 120 880 105 865 100
0.20 1320 285 1080 190 900 125 805 105 700 85
0.30 1290 295 1055 200 875 135 750 110 640 90
0.40 1265 310 1010 205 825 145 710 120 595 95
0.50 1230 315 990 215 790 155 660 125 535 100
0.60 1190 330 945 230 750 165 630 135 500 110
0.70 1165 340 915 235 705 170 570 140 435 115
0.80 1130 350 880 245 670 180 535 150 380 120
ML180UH070E36B PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1415 265 1330 170 1215 135 1175 125 1075 85
0.10 1415 280 1295 170 1145 145 1130 130 955 95
0.20 1355 290 1225 185 1110 150 1080 140 885 100
0.30 1330 300 1190 200 1060 160 1035 155 825 110
0.40 1290 310 1155 205 1015 175 970 160 770 120
0.50 1245 325 1115 215 980 180 930 170 695 125
0.60 1225 335 1045 230 920 190 865 180 625 135
0.70 1190 350 1000 235 855 205 790 190 540 140
0.80 1160 365 925 245 790 205 735 200 445 145
ML180UH090E48B PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1785 380 1570 270 1440 220 1395 190 1190 120
0.10 1755 395 1535 275 1420 230 1350 205 1140 130
0.20 1730 415 1505 290 1380 245 1310 215 1110 145
0.30 1690 435 1460 305 1345 260 1275 230 1065 155
0.40 1645 440 1435 320 1310 270 1240 240 1010 165
0.50 1615 455 1395 335 1265 285 1180 255 955 180
0.60 1590 470 1350 350 1210 290 1150 265 915 185
0.70 1545 475 1300 360 1175 305 1095 275 860 200
0.80 N/A N/A 1270 370 1140 310 1040 285 820 210

ML180UHE / Page 14
BLOWER DATA
ML180UH110E60C PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2230 635 1945 430 1715 295 1555 230 1470 185 2315 645 1990 415 1780 300 1610 230 1510 200
0.10 2180 655 1905 445 1690 305 1510 240 1340 175 2260 655 1945 425 1740 315 1550 240 1400 185
0.20 2135 680 1865 465 1630 330 1470 260 1280 190 2210 680 1895 450 1680 335 1510 255 1350 200
0.30 2090 695 1830 480 1595 345 1440 275 1235 200 2165 700 1850 465 1650 355 1455 275 1285 210
0.40 2050 715 1785 495 1550 360 1385 285 1175 210 2130 715 1830 485 1585 365 1395 285 1230 225
0.50 2025 730 1740 520 1500 375 1340 300 1130 225 2095 730 1770 500 1535 385 1365 300 1175 235
0.60 2010 750 1710 535 1470 390 1305 320 1080 240 2055 755 1725 515 1495 400 1305 315 1135 250
0.70 1965 755 1670 555 1420 410 1255 330 1015 255 2000 765 1675 535 1465 410 1255 325 1080 265
0.80 1905 785 1635 560 1380 425 1215 350 975 270 1965 785 1640 555 1400 425 1210 345 1025 275
ML180UH090E60C PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2255 640 1940 420 1750 310 1580 230 1485 185 2290 655 1980 425 1775 310 1605 235 1495 195
0.10 2200 655 1910 440 1705 315 1535 240 1385 190 2250 675 1945 445 1730 320 1555 245 1400 190
0.20 2150 675 1865 450 1655 340 1490 260 1340 205 2210 695 1885 465 1680 340 1510 265 1350 205
0.30 2125 695 1835 475 1635 355 1450 275 1285 215 2165 715 1850 475 1645 355 1470 275 1285 215
0.40 2090 715 1800 495 1585 370 1405 285 1235 230 2135 720 1810 490 1595 370 1410 290 1225 230
0.50 2060 735 1760 510 1545 385 1370 305 1200 245 2070 735 1765 515 1545 390 1370 305 1180 245
0.60 2020 750 1725 525 1515 405 1320 320 1145 255 2030 760 1715 530 1495 405 1325 320 1140 255
0.70 1980 765 1680 540 1465 420 1265 330 1105 270 1990 775 1685 540 1450 425 1265 330 1095 270
0.80 1935 785 1635 560 1420 435 1225 350 1055 285 1950 795 1645 560 1415 435 1225 345 1040 285
ML180UH135E60D PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2495 755 2295 590 2045 435 1845 315 1650 230 2365 725 2295 575 2005 410 1820 300 1635 235
0.10 2440 780 2220 620 2015 445 1820 330 1615 245 2350 745 2210 595 2000 435 1745 320 1530 230
0.20 2390 790 2175 640 1935 470 1735 350 1550 255 2330 775 2175 625 1945 455 1730 330 1490 250
0.30 2360 805 2140 655 1895 490 1720 370 1485 275 2245 785 2135 645 1895 475 1655 355 1425 265
0.40 2285 835 2125 675 1850 510 1660 380 1455 290 2215 810 2085 660 1840 495 1600 375 1385 285
0.50 2240 860 2060 690 1815 535 1610 400 1415 310 2175 825 2045 680 1815 505 1590 390 1340 290
0.60 2225 865 2015 715 1785 550 1535 420 1330 320 2125 845 1995 700 1765 530 1525 405 1300 310
0.70 2160 895 1955 735 1755 570 1500 440 1265 340 2095 865 1950 710 1700 545 1485 420 1260 325
0.80 2105 905 1925 750 1715 580 1435 450 1215 345 2065 880 1890 725 1680 565 1415 445 1205 345

NOTE - Due to Lennox’ ongoing commitment to quality, Specications, Ratings and Dimensions subject to change without notice and without incurring liability.
Improper installation, adjustment, alteration, service or maintenance can cause property damage or personal injury.
Installation and service must be performed by a qualied installer and servicing agency. ©2011 Lennox Industries, Inc.
Visit us at www.lennox.com
For the latest technical information, www.lennoxdavenet.com
Contact us at 1-800-4-LENNOX