Lennox Merit Series, ML18007036A-E, ML18007036A-EC, ML18011060C-E, ML18011060C-EC Installation Instructions Manual
...
1
INSTALLATION INSTRUCTIONS
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
LENNOX MERIT SERIES™ GAS FURNACE
506998-01
08/2013 Supersedes 06/2012
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 installer (or
equivalent), service agency or the gas
supplier.
WARNING
!
!
As with any mechanical equipment, personal
injury can result from contact with sharp
sheet metal edges. Be careful when you
handle this equipment.
CAUTION
!
TABLE OF CONTENTS
Lennox Merit Series™ Furnace Specications ........... 2
Lennox Merit Series
™
Gas Furnace ............................ 3
Shipping and Packing List........................................... 3
Requirements ............................................................... 3
General ......................................................................... 4
Shipping and Packing List........................................... 4
General ......................................................................... 4
Location/Placement ..................................................... 4
Duct System ................................................................. 5
Installing Optional Cooling Coil ................................... 5
Venting ......................................................................... 6
General Lennox Merit Series
™
E or EC Series ......... 17
Gas Piping .................................................................. 17
Electrical .................................................................... 18
Filters ......................................................................... 19
Duct System ............................................................... 19
Venting ....................................................................... 19
Gas Piping .................................................................. 19
Electrical .................................................................... 21
Integrated Control ...................................................... 22
Lennox Merit Series
™
Schematic wiring diagram ... 23
Unit Start-Up .............................................................. 24
Gas Pressure Adjustment .......................................... 25
Proper Combustion .................................................... 26
High Altitude .............................................................. 26
Other Unit Adjustments ............................................. 27
Service ....................................................................... 28
Repair Parts ............................................................... 31
This is a safety alert symbol and should never be ignored.
When you see this symbol on labels or in manuals, be alert to
the potential for personal injury or death.
2
MODEL DIMENSIONS mm
A B C D
ML18007036A-E 456 512 80 -
ML18007036A-EC 456 512 80 533
ML18011060C-E 544 600 123 -
ML18011060C-EC 544 600 123 438
ML18013560D-E 633 690 167 -
ML18013560D-EC 633 690 167 438
LENNOX MERIT SERIES™ FURNACE SPECIFICATIONS
NOTE: DUCT CONNECTIONS ARE INTERCHANGEABLE FROM SIDE TO SIDE
3
LENNOX MERIT SERIES™ GAS FURNACE
SHIPPING AND PACKING LIST
REQUIREMENTS
The Lennox Merit Series™ unit is shipped ready for
installation for external applications.
Package 1 of 1 contains:
1 x Assembled Lennox Merit Series
™
unit
1 x Bag assembly containing the following:
2 x Screws
1 x Snap bushing
1 x Snap plug
1 x Wire tie
1 x Vent warning label
1 x Owner’s manual
1 x Bag assembly containing the following:
1 x 2.5m Power cord
The following items may be ordered separately:
1 x Thermostat
1 x Propane/LP changeover kit
1 x High altitude kit
Check equipment for shipping damage. If you nd any
damage, immediately contact the last carrier.
The Lennox Merit Series
™
furnace is approved for
installation for outside of building, with clearances as listed
in Figure 6. (Accessibility and service clearances must take
precedence over re protection clearances). Installation of
Lennox forced air central furnaces must be in accordance
with these instructions, local gas tting regulations,
municipal building codes, electrical wiring regulations and
the current edition of the Australian Gas Installation Code
(AS5601).
Adequate clearance must be made around the air openings
into the vestibule area. Provisions shall be made for proper
operation and for combustion air and ventilation air supply
according to the current edition of the Australian Gas
Installation Code (AS5601).
NOTE: For installation on combustible oors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood ooring.
For installation in a residential garage, the furnace must be
installed so that the burner(s) and the ignition source are
located no less than 457 mm (18 in) above the oor.
The furnace must be located or protected to avoid physical
damage by vehicles. When a furnace is installed in a public
garage, hangar, or other building that has a hazardous
atmosphere, the furnace must be installed according to
recommended good practice requirements and current
edition of the Australian Gas Installation Code (AS5601).
Unit must be adjusted to obtain a temperature rise within
the range specied on appliance rating plate. This Lennox
Merit Series
™
furnace must be installed so that its electrical
components are protected from water.
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel ow arrangement, a damper (or other means
to control the ow of air) must adequately prevent chilled
air from entering the furnace. If the damper is manually
operated, it must be equipped to prevent operation of either
the heating or the cooling unit, unless it is in the full HEAT or
COOL setting.
When installed, this furnace must be electrically
grounded according to local codes.
All eld wiring must comply with the current edition
of Australian Standard AS3000.
The blower access panel must be securely
in place when the blower and burners are
operating. Gas fumes, which could contain
carbon monoxide, can be drawn into living
space resulting in personal injury or death.
WARNING
!
4
GENERAL GENERAL
LOCATION / PLACEMENT
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the
following general recommendations must be considered
when installing a Lennox Merit Series
™
furnace:
Place the furnace as close to the center of the air
distribution system as possible.
Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
These instructions are intended as a general guide and
do not supersede local codes in any way. Consult AGA.
AG-601 INSTALLATION CODE or authorities having
jurisdiction before installation.
The Lennox Merit Series
™
furnace is approved for
installation outside the building only with clearances as listed
in Table 1.
Installation of Lennox outdoor central furnaces must be
in accordance with these instructions, local gas tting
regulations, municipal building codes, electrical wiring
regulations and the current edition of the Australian Gas
Installation Code (AG 601).
The following general recommendations should be considered
when installing the Lennox Merit Series
™
Gas Furnace.
The Lennox Merit Series
™
Gas Furnace can be installed in
either right or left hand mode.
NOTE: On some models - 1/3 and 1/2 hp blower motors
are equipped with either four exible mounting legs or three
exible legs and one rigid leg. The rigid leg is equipped with
a shipping bolt and a at white plastic washer (rather than
the rubber mounting grommet used with a exible mounting
leg). This shipping bolt and at washer must be removed
before the furnace is put into operation. Once the shipping
bolt and washer are removed, the rigid leg will not touch the
fan housing.
Select a unit location that will allow for required clearances
per local AG 601 codes and in Table 1.
Also consider gas supply connections, electrical supply, vent
termination and installation and service clearances (600mm
front).
Accessibility and service clearances must not take
precedence over re protection clearances.
The Lennox Merit Series
™
Gas Furnace furnace should be
set on a eld-provided platform to keep the unit base out
of water. The unit is equipped with base rails, which lift the
bottom of the unit off of the platform. Unit must be levelled
using shims or levelling bolts. Knock-outs are provided in
unit base to install eld-provided levelling bolts.
Do not install the furnace in a corrosive
or contaminated atmosphere. Meet all
combustion and ventilation air requirements,
as well as all local codes.
CAUTION
!
SHIPPING AND PACKING LIST
Package 1 of 1 contains:
1 x Assembled unit
1 x Flue adapter/cowl eld–installed
2 x Starting collars
The following additional items may be ordered separately,
if required:
1 x Cooling coil
1 x Thermostat
1 x LP Changeover kit
Check unit for shipping damage. Receiving party should
contact last carrier immediately if any shipping damage is
found.
5
DUCT SYSTEM
INSTALLING OPTIONAL
COOLING COIL
The unit is provided with knock-outs for either right or leftside connection of the supply and return air plenums.
Refer to the dimensioned drawing on page 2 to locate and
size the plenum entry into the side of the building.
Cover plates are provided to seal the unused knock-outs and
these become convenient access ports for regular service
and maintenance.
Size and install supply and return air duct system using
industry-approved standards that result in a quiet and
low-static system with uniform air distribution. The furnace
access panel must always be in place when the unit is in
operation and it must not allow leaks into the duct system.
Construct a protective covering made of suitable materials to
shield the plenum connections from rain. Rain shield should
be attached to the side of the unit cabinet above the plenum
connections and span the distance to the building wall above
the plenum entry into the structure. Rain shield connections
must be caulked so that they are weather-tight.
If optional cooling coil is to be used, install coil according to
the steps indicated below:
1. Remove Lennox Merit Series
™
Gas Furnace unit rear
panel.
NOTE: Installation of larger evaporator coils may require
removal of unit top panel as well.
2. Place cooling coil on unit coil deck in cooling
compartment.
3. Using template provided with the coil, cut holes for
refrigeration and drain piping. Align coil with piping holes
in panel. Seal holes around piping.
4. Reinstall Lennox Merit Series
™
panel.
5. Make refrigerant piping connections to condensing unit
per local codes and sound plumbing practices.
6
Ref. Item
Minimum clearances mm
Natural draft Fan assisted
A Below eaves, balconies and other projections:
• Appliances up to 50 Mj/h input
• Appliances over 50 Mj/h input
300
500
200
300
B From the ground, above a balcony or other surface* 300 300
C From a return wall or external corner* 500 300
D From a gas meter (M) (see 4.7.11 for vent terminal location of regulator) 1000 1000
E From an electricity meter or fuse box (P) 500 500
F From a drain pipe or soil pipe 150 75
G Horizontally from any building structure* or obstruction facing a terminal 500 500
H From any other ue terminal, cowl, or combustion air intake* 500 300
J Horizontally from an openable window, door, non-mechanical air inlet, or any other
opening into a building with the exception of sub-oor ventilation:
• Appliances up to 150 Mj/h input
• Appliances over 150 Mj/h input up to 200 Mj/h input
• Appliances over 200 Mj/h input
• All fan-assisted ue appliances, in the direction of discharge
500
1500
1500
1500
300
500
1500
K From a mechanical air inlet, including a spa blower 1500 1000
N Vertically below an openable window, non-mechanical air inlet, or any other opening
into a building with the exception of sub-oor ventilation:
• Space heaters up to 50 Mj/h input
• Other appliances up to 50 Mj/h input
• Appliances over 50 Mj/h input and up to 150 Mj/h input
• Appliances over 150Mj/h input
150
500
1000
1500
150
500
1000
1500
*Unless appliance is approved for closer installation
NOTES:
1. All distances are measured to the nearest part of the terminal.
2. Prohibited area below electricity meter or fuse box extends to
ground level.
3. See Clause 5.13.6.6 for restrictions on a ue terminal under a
covered area.
4. See Appendix J, Figures J2(a) and J3(a), for clearances required from a
ue terminal to an LP Gas cylinder. A ue terminal is considered to be a
source of ignition.
5. For appliances not addressed above, approval shall be obtained from
the Authority.
Figure 1
VENTING
The Lennox Merit Series™ unit is shipped standard for top ue discharge. A ue adapter is supplied with the furnace. It must
be installed on the outside of the furnace.
FLUE TERMINATION
CLEARANCES
7
VENTING
A 4−inch diameter ue transition is factory-inst
alled on the
combustion
air inducer outlet of all models. Figure 3
shows
the combustion air inducer as shipped from the
factor
y.
FIGURE 2
Mounting Screws Location
Mounting Screws
Flue Transition
Upow Position
FIGURE 3
UPFLOW POSITION
Top Vent Discharge
FLOW
AIR
Collector Box
Vent Pipe
Flue
Transition
Pressure
Switch
Make−Up
Box
IMPORTANT
The unit will not vent properly with the ue transition
pointed down in the 6 o’clock position.
The combustion air inducer may be rotated clockwise or counterclockwise by 90° to allow for top or
side vent discharge in all applications. When the unit
is installed, the ue transition must be in the 9
o’clock, 12 o’clock or 3 o’clock position.
If
necessary, reposition the combustion air inducer, pres-
sure
switch and/or make−up box as needed per the follow-
ing
steps. See gures 3 through 9.
1 − Remove the four mounting screws (gure 2) which
secure the combustion air inducer / pressure switch
assembly to the orice plate. Lift the assembly and rotate it 90 degrees clockwise or counterclockwise to ei-
ther the 3 o’clock position or to 9 o’clock position. Re−
secure with four screws. Gasket should be left in place.
2 − Use tin snips to cut preferred opening on the cabinet
for repositioning the ue outlet. Use the cut−out piece
as a cover plate to patch unused opening on cabinet.
UPFLOW POSITION
Left Side Vent Discharge
FIGURE 4
Cut combustion air inducer tubing from 225mm to 125mm
to avoid
interference with inducer motor
Remove make−up box assembly (2 screws) and cut wire tie to
free make−up box wires. Re−install make−up box on other side
of cabinet.
Re−secure make−up box wires: Either pull excess wires
through the blower compartment and secure using supplied
wire tie, or coil excess wire and secure to the gas manifold.
FLOW
AIR
Make−Up
Box
Pressure
Switch
Flue
Transition
Vent Pipe
Collector Box
Gas supply piping must be brought into the unit from the right
side in order to accommodate the ue pipe.
UPFLOW POSITION
Right Side Vent Discharge
FIGURE 5
FLOW
AIR
Cover Plate
Flue Transition
Vent Pipe
Pressure
Switch
Make−Up
Box
Collector Box
Cut combustion air inducer tubing from 225mm to 125mm
to avoid
interference with inducer motor
8
VENTING
HORIZONTAL LEFT POSITION
Top Vent Discharge
FIGURE 6
Disconnect pressure switch hose from barbed tting on the
pressure switch assembly. Remove pressure switch assembly
(1 screw) and cut wire tie to free pressure switch wires.
Re−
install pressure switch on the other side of orice plate and
re−connect pressure switch hose.
Re−secure pressure switch wires: Either pull excess wires
through the blower compartment and secure using supplied
wire tie, or coil excess wire and secure to the gas manifold.
Pressure
Switch
Vent Pipe
Flue
Transition
Cover Plate
Make−Up Box
Collector Box
FLOW
AIR
FIGURE 7
Make−Up Box
Collector Box
Vent Pipe
Pressure Switch
HORIZONTAL LEFT POSITION
Side Vent Discharge
Disconnect pressure switch hose from barbed tting on the
pressure switch assembly. Remove pressure switch assembly
(1 screw) and cut wire tie to free pressure switch wires. Re−
install pressure switch on the other side of orice plate and re−
connect pressure switch hose.
Re−secure pressure switch wires: Either pull excess wires
through the blower compartment and secure using supplied
wire tie, or coil excess wire and secure to the gas manifold.
FLOW
AIR
Cut combustion air inducer tubing from 225mm to 125mm
to avoid
interference with inducer motor
HORIZONTAL RIGHT POSITION
Top Vent Discharge
FIGURE 8
Remove make−up box assembly (2 screws) and cut wire tie to
free make−up box wires. Re−install make−up box on other side
of cabinet.
Re−secure make−up box wires: Either pull excess wires through
the blower compartment and secure using supplied wire tie, or
coil excess wire and secure to the gas manifold.
FLOW
AIR
Flue
Transition
Vent Pipe
Pressure Switch
Cover Plate
Make−Up Box
Collector Box
Gas supply piping must be brought into the unit from the bot-
tom in order to accommodate the ue pipe.
Cut combustion air inducer tubing from 225mm to 125mm
to avoid
interference with inducer motor
HORIZONTAL RIGHT POSITION
Side Vent Discharge
FIGURE 9
FLOW
AIR
Pressure Switch
Flue Transition
Collector Box
Make−Up Box
9
VENTING
The Lennox Merit SeriesTM Gas Furnace units
are classied as fan−assisted
Category I furnaces
when vertically vented according to the latest edition
of National Fuel Gas Code (NFPA 54 / ANSI Z223.1)
in the USA. A fan−assisted Category I furnace is an
appliance equipped with an integral mechanical means
to either draw or force combustion products through the
combustion chamber and/or heat exchanger. The internal
unit is not approved for use with horizontal venting.
NOTE −
Use these instructions as a guide. They do not supersede local codes. This furnace must be vented according to all local codes these installation instructions, and the
provided venting tables in these instructions
The venting tables in this manual were extracted from the
National Fuel Gas Code (NFPA 54 / ANSI Z223.1) and are
provided as a guide for proper vent installation. Proper application, termination, construction and location of vents
must conform to local codes having jurisdiction.
of local codes, the NFGC serves as the
dening document.
Refer to the tables and the venting information contained in
these instructions to properly size and install the venting
system.
Use self−drilling sheet metal screws or a mechanical fastener to rmly secure the vent pipe to the round collar of the
ue transition. If self−drilling screws are used to attach the
vent pipe, it is recommended that three be used. Drive one
self−drilling screw through the front and one through each
side of the vent pipe and collar. See gure 10.
Install the rst vent connector elbow at a minimum of six
inches (152 mm) from the furnace vent outlet. See gure
10.
Venting Using a Masonry Chimney
The following additional requirements apply when a lined
masonry chimney is used to vent this furnace.
Masonry chimneys used to vent Category I central fur-
naces must be either tile-lined or lined with a listed metal
lining system or dedicated gas vent. Unlined masonry
chimneys are prohibited. See gures 11 and 12 for common venting.
A chimney with one or more sides exposed to the outside of
the structure is considered to be an exterior chimney.
An exterior masonry chimney that is not tile−lined must be
lined with B1 vent or a listed insulated exible metal vent.
An exterior tile−lined chimney that is sealed and
capped
may be lined with a listed uninsulated exible metal vent.
If the existing chimney will not accommodate a listed metal
liner, either the chimney must be rebuilt to accommodate
one of these liners or an alternate approved venting method must be found.
Insulation for the exible vent pipe must be an encapsulated berglass sleeve recommended by the exible vent
pipe manufacturer. See gure 11.
IMPORTANT
Once the venting system is installed, attach
connected Vent" warning sticker to a visible area of
the plenum near the vent pipe. See gure 10. The
warning sticker is provided in the bag assembly. Order kit 66W04 for additional stickers.
WARNING
Asphyxiation hazard. The exhaust vent for this furnace must be securely connected to the furnace ue
transition at all times.
FIGURE 10
FLUE TRANSITION
COLLAR
VENT PIPE
(min. 150mm length)
“DISCONNECTED VENT”
WARNING
STICKER
FLUE
TRANSITION
COLLAR
VENT CONNECTION UPFLOW AND HORIZONTAL POSITION
VENT PIPE
(min. 150mm length)
“DISCONNECTED VENT”
WARNING
STICKER
In the absence
10
VENTING
FIGURE 11
Common Venting Using Metal−Lined Masonry Chimney
4 in. (102 mm)
minimum
MIN. LENGTH −− AS
SHORT AS PRACTICAL
MAX. LENGTH
−− SEE NOTE 1
BELOW.
SEALED
PERMANENTLY
SEALED FIREPLACE
OPENING
EXTERIOR
CHIMNEY WITH
METAL
LINER
VENT CONNECTOR
NOTE 1 − Refer to the provided venting tables for installations. Refer
to the capacity requirements shown in the provided venting tables.
OTHER
APPLIANCE
FURNACE
5 ft. (1.5 m)
minimum
DO
NOT insulate the space between the liner and the
chimne
y wall with puffed mica or any other loose gran-
ular insulating material.
IMPORTANT
SINGLE appliance venting of a fan-assisted furnace
into a tile-lined masonry chimney (interior or outside
wall) is PROHIBITED. The chimney must rst be lined
with either type B1 vent or an insulated single wall
exible vent lining system which has been sized according to the provided venting tables and the vent
pipe manufacturer’s instructions.
A
fan−assisted furnace may be commonly vented into an
existing
lined masonry chimney if the following conditions
are met:
The chimney is currently serving at least one draf thood−
equipped appliance;
The vent connectors and chimney are sized according
to the provided venting tables.
If
type B1 double-wall vent is used inside a chimney, no oth-
er appliance can be vented into the chimney
. The outer wall
of type B1 vent pipe must not be exposed to ue product
s.
A
type B1 vent or masonry chimney liner shall terminate
above the
roof surface with a listed cap or a listed roof as-
sembly
according to the terms of their respective listings
and the vent manufacturer’s instructions.
When inspection reveals that an existing chimney is not
safe for the intended purpose, it shall be rebuilt to conform
to nationally recognised standards, lined or relined with
suitable materials, or replaced with a gas vent or chimney
suitable for venting the units. The chimney
passageway
must be checked periodically to ensure that it is clear and
free of obstructions.
Do not install a manual damper, barometric draft regulator,
or ue restrictor between the furnace and the chimney.
Never connect a Category I appliance to a chimney that is
servicing a solid−fuel appliance. If a replace chimney ue
is used to vent this appliance, the replace opening must
be permanently sealed.
A type B or listed chimney lining system that passes
through an unused masonry chimney ue is not considered
to be exposed to the outdoors.
General Venting Requirements
Vent all internal furnaces according to these instructions:
1 −Vent diameter recommendations and maximum allow-
able piping runs are found in the provided venting
tables.
2 −In no case should the vent or vent connector diameter
be less than the diameter specied in the provided
venting tables.
3 −The minimum vent capacity determined by the sizing
tables must be less than the low re input rating and the
maximum vent capacity must be greater than the high
re input rating.
4 −Single appliance vents − If the vertical vent or tile-lined
chimney has a larger diameter or ow area than the
vent connector, use the vertical vent diameter to de-
termine the minimum vent capacity and the vent
connector diameter to determine the maximum vent
capacity. The ow area of the vertical vent, however,
shall not exceed 7 times the ow area of the listed appliance categorized vent area, drafthood outlet area or
ue collar area unless designed according to approved
engineering methods.
5 −Multiple appliance vents − The ow area of the largest
section of vertical vent or chimney shall not exceed 7
times the smallest listed appliance categorized vent
area, drafthood outlet area or ue collar area unless designed according to approved engineering methods.
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