Nortek KG7TC User manual

Two-Stage Condensing Gas Furnaces With Fixed & Variable Speed Blowers 95.0% AFUE
INSTALLATION INSTRUCTIONS
*TC Upflow / Horizontal Furnace
WARNING
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could result in serious injury or property damage.
• Installation and service must be performed by a qualified installer, service agency or the gas
supplier.
• Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or
any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a neighbors phone. Follow the gas suppliers instructions.
• If you cannot reach your gas supplier, call the fire department.
DO NOT DESTROY. PLEASE READ CAREFULLY & KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.

2
TABLE OF CONTENTS
IMPORTANT SAFETY INFORMATION..............................3
REQUIREMENTS & CODES ..............................................3
Combustion Air Quality ....................................................4
Heating Load....................................................................5
Installation in a Garage....................................................5
Clearances to Combustible Materials ..............................5
Operation of Furnace During Construction ......................5
COMBUSTION AIR & VENTING REQUIREMENTS ..........6
Direct Vent Systems ........................................................7
Conventional Vent Systems - Confined Spaces ..............7
Air From Inside..............................................................7
Outdoor Air from a Crawl Space or Vented Attic...........7
Outdoor Air Using Vertical Ducts ..................................8
Outdoor Air Using Horizontal Ducts ..............................8
Air Directly Through an Exterior Wall ............................8
Alternate Method of Providing Air from Outside:...........8
Conventional Vent Systems - Unconfined Spaces ..........9
Category IV Venting.........................................................9
Vent Pipe Material.........................................................9
Vent Pipe Length & Diameter........................................10
Vent Pipe Installation ....................................................10
Outdoor Terminations - Horizontal Venting...................11
Outdoor Terminations - Vertical Venting .......................11
Vent Freezing Protection...............................................11
Existing Installations......................................................12
Condensate Disposal.......................................................12
CIRCULATING AIR REQUIREMENTS...............................12
Plenums & Air Ducts........................................................12
Return Air Connections....................................................13
Upflow & Horizontal Furnaces.......................................13
Supply Air Connections....................................................13
Acoustical Treatments .....................................................13
FURNACE INSTALLATION................................................14
General Requirements.....................................................14
Upflow Furnaces..............................................................14
Horizontal Furnaces.........................................................14
Inducer & Venting Options...............................................15
Inducer Assembly Rotation ...........................................15
Pressure Switch Tubing ................................................15
Accessories......................................................................16
Finish Flange.................................................................16
Rubber Grommets.........................................................16
PVC Components .........................................................16
Typical Orientation.................................................16
Alternate Orientation..............................................17
Condensate Drain Lines................................................17
Bottom Panel Removal ....................................................17
Alternate Bottom Panel Removal..................................17
GAS SUPPLY & PIPING.....................................................18
Leak Check......................................................................19
High Altitude Application (Natural Gas Only) ...................19
Converting from Natural Gas to LP / Propane .................20
ELECTRICAL WIRING .......................................................21
Line Voltage Wiring..........................................................21
Grounding ........................................................................22
Thermostat / Low Voltage Connections...........................22
Single Stage AC & Single Stage Thermostat................22
Single Stage AC & Two Stage Thermostat...................22
Two-Stage AC & Two-Stage Thermostat......................22
Autostaging for Single Stage Thermostats ......................23
Autostaging for Two-Stage Thermostats .........................23
Blower Speed Configuration ............................................23
Fixed Speed Blower Applications..................................23
Variable Speed Blower Applications .............................23
Dehumidification Options.................................................23
Heat Anticipator ...............................................................23
START-UP & ADJUSTMENTS...........................................24
Pre-Start Check List.........................................................24
Start-up Procedures.........................................................24
Verifying & Adjusting Input Rate ......................................24
Verifying & Adjusting Temperature Rise ..........................24
Verifying Burner Operation ..............................................25
Verifying Operation of the Supply Air Limit Switch...........25
OPERATING SEQUENCE..................................................25
Heating Cycle...................................................................25
Cooling Cycle...................................................................26
Fan Mode.........................................................................26
MAINTENANCE..................................................................26
FIGURES & TABLES..........................................................27
Figure 26. *TC Cabinet Dimensions..............................27
Gas Information ...............................................................28
Table 5. Gas Flow Rates...............................................28
Table 6. Gas Pipe Capacities........................................28
Table 7. High Altitude Deration - Propane Gas.............29
Table 8. Natural Gas Heating Values............................29
Table 9. High Altitude Deration - Natural Gas with
HIGH Heating Value........................................30
Table 10. High Altitude Deration - Natural Gas with
LOW Heating Value ......................................30
Electrical Information .......................................................31
Figure 27. Two-Stage Fixed Speed Motor Control
Board ...........................................................31
Figure 28. Two-Stage Variable Speed Motor Control
Board ...........................................................31
Figure 29. Two-Stage Furnace Control Board ..............31
Figure 30. Wiring Diagram for Two-Stage, Fixed
Speed Upflow Furnaces...............................32
Figure 31. Wiring Diagram for Two-Stage, Variable
Speed Upflow Furnaces...............................33
Venting Information..........................................................34
Table 11. Vent Termination Clearances........................34
Figure 32. Horizontal & Vertical Venting
(A Width Cabinets).......................................35
Figure 33. Horizontal & Vertical Venting
(B, C, & D Width Cabinets) ..........................36
Figure 34. Upflow Venting Options
(A Width Cabinets).......................................37
Figure 35. Upflow Venting Options
(B, C, & D Width Cabinets) ..........................38
Figure 36. Horizontal Venting Options
(A Width Cabinets).......................................39
Figure 37. Horizontal Venting Options
(B, C, & D Width Cabinets) ..........................40
TROUBLESHOOTING........................................................41
Table 12. Furnace Control Board Fault Conditions.......41
Table 13. Motor Control Board Fault Conditions...........41
FURNACE COMPONENTS ................................................41
Figure 38. Component Locations..................................42
INSTALLATION CHECKLIST.............................................44

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prior to performing the installation and operational checkout
of the equipment.
• Use caution when handling this appliance or removing
components. Personal injury can occur from sharp metal
edges present in all sheet metal constructed equipment.
• Do not store any of the following on, or in contact with, the
unit: Rags, brooms, vacuum cleaners, or other cleaning
tools, spray or aerosol cans, soap powders, bleaches,
waxes, cleaning compounds, plastics or plastic containers,
paper bags or other paper products, gasoline, kerosene,
cigarette lighter fluid, dry cleaning fluids, paint thinners,
or other volatile fluids.
• The installer should become familiar with the units wiring
diagram before making any electrical connections to the
unit. See Figure 30 (page 32)& Figure 31 (page 33)or
the unit wiring label.
• Always reinstall the doors on the furnace after
servicing. Do not operate the furnace without all doors
and covers in place.
REQUIREMENTS & CODES
WARNING:
The safety information listed below must be
followed during the installation, service, and
operation of this furnace. Failure to follow safety
recommendations could result in possible
damage to the equipment, serious personal
injury or death.
• This furnace must be installed in accordance with these
instructions, all applicable local building codes and the
current revision of the National Fuel Gas Code (NFPA54/
ANSI Z223.1) or the Natural Gas and Propane Installation
Code, CAN/CGA B149.1.
• Use only with type of gas approved for this furnace. Refer
to the furnace rating plate.
• Install this furnace only in a location and position as specified
on page 5.
• Provide adequate combustion and ventilation air to the
furnace space as specified in the Combustion Air and
Ventilation Requirements section (page 6).
• Provide adequate clearances around the vent air intake
terminal as specified in Figure 7 (page 10), Figure 8 (page
10), Figure 9 (page 10), & Figure 10 (page 11).
• Combustion products must be discharged outdoors.
Connect this furnace to an approved vent system only,
as specified on page 9.
• Never test for gas leaks with an open flame. Use
a commercially available soap solution to check all
connections. See page 19.
• This furnace is designed to operate with a maximum
external pressure rise of 0.5 inches of water column.
Consult the rating plate for the proper circulating air flow
and temperature rise. It is important that the duct system
be designed to provide the correct flow rates and external
pressure rise. An improperly designed duct system can
result in nuisance shutdowns, and comfort or noise issues.
• When supply ducts carry air circulated by the furnace to
areas outside the space containing the furnace, the return
air shall also be handled by duct(s) sealed to the furnace
casing and terminating in the conditioned space. See page
12.
IMPORTANT SAFETY INFORMATION
INSTALLER: Please read all instructions before servicing
this equipment. Pay attention to all safety warnings and any
other special notes highlighted in the manual. Safety markings
are used frequently throughout this manual to designate a
degree or level of seriousness and should not be ignored.
WARNING - indicates a potentially hazardous situation that
if not avoided, could result in personal injury or death.
CAUTION - indicates a potentially hazardous situation that
if not avoided, may result in minor or moderate injury or
property damage.
WARNING:
The safety information listed in this manual must
be followed during the installation, service, and
operation of this unit. Unqualified individuals
should not attempt to interpret these instructions
or install this equipment. Failure to follow safety
recommendations could result in possible
damage to the equipment, serious personal
injury or death.
WARNING:
Unless otherwise noted in these instructions,
only factory authorized kits or accessories may
be used with or when modifying this product.
WARNING:
Improper installation, service, adjustment, or
maintenance may cause explosion, fire, electrical
shock or other hazardous conditions which may
result in personal injury or property damage.
Unless otherwise noted in these instructions,
only factory authorized kits or accessories may
be used with this product.
WARNING:
Do not install this furnace if any part has been
submerged underwater. Aflood damaged furnace
is extremely dangerous. Attempts to use the
furnace may result in fire or explosion. A qualified
service agency should be contacted to inspect the
furnace and to replace any electrical or control
system parts that have been wet or under water.
• To minimize equipment failure or personal injury, it is
essential that only qualified individuals install, service, or
maintain this equipment. If you do not posses mechanical
skills or tools, call your local dealer for assistance.
• Follow all precautions in the literature, on tags, and on
labels provided with the equipment. Read and thoroughly
understand the instructions provided with the equipment

4
• A gas-fired furnace for installation in a residential garage
must be installed as specified on page 5.
• This furnace is not approved for installation in mobile homes.
Installing this furnace in a mobile home could cause fire,
property damage, and/or personal injury.
• The Commonwealth of Massachusetts requires compliance
with regulation 248 CMR 4.00 and 5.00 for installation of
through – the – wall vented gas appliances as follows:
1. For direct-vent appliances, mechanical-vent heating
appliances or domestic hot water equipment, where the
bottom of the vent terminal and the air intake is installed
below four feet above grade the following requirements
must be satisfied:
a.) A carbon monoxide (CO) detector and alarm shall be
placed on each floor level where there are bedrooms.
The detector shall comply with NFPA 720 (2005
Edition) and be mounted in the living area outside
the bedroom(s).
b.) A (CO) detector shall be located in the room that
houses the appliance or equipment and shall:
• Be powered by the same electrical circuit as the
appliance or equipment. Only one service switch
shall power the appliance and the (CO) detector;
• Have battery back-up power;
• Meet ANSI/UL 2034 Standards and comply with
NFPA 720 (2005 Edition); and Approved and listed
by a Nationally Recognized Testing Laboratory as
recognized under 527 CMR.
c.) A Product-approved vent terminal must be used, and
if applicable, a product-approved air intake must be
used. Installation shall be in strict compliance with the
manufacturer’s instructions. A copy of the installation
instructions shall remain with the appliance or
equipment at the completion of the installation.
d.) A metal or plastic identification plate shall be mounted
at the exterior of the building, four feet directly above
the location of vent terminal. The plate shall be of
sufficient size, easily read from a distance of eight
feet away, and read “Gas Vent Directly Below”.
2. For direct-vent appliances, mechanical-vent heating
appliances or domestic hot water equipment where the
bottom of the vent terminal and the air intake is installed
above four feet above grade the following requirements
must be satisfied:
a.) A (CO) detector and alarm shall be placed on each
floor level where there are bedrooms. The detector
shall comply with NFPA 720 (2005 Edition) and be
mounted in the living area outside the bedroom(s).
b.) The (CO) detector shall:
• Be located in the room that houses the appliance
or equipment;
• Be hard-wired or battery powered or both.
• Shall comply with NFPA 720 (2005 Edition).
c.) A product-approved vent terminal must be used, and
if applicable, a product-approved air intake must be
used. Installation shall be in strict compliance with the
manufacturer’s instructions. A copy of the installation
instructions shall remain with the appliance or
equipment at the completion of the installation.
The information listed below is for reference purposes only
and does not necessarily have jurisdiction over local or state
codes. Always consult with local authorities before installing
any gas appliance.
Combustion & Ventilation Air
• US: National Fuel Gas Code (NFGC), Air for Combustion and
Ventilation
• CANADA: Natural Gas and Propane Installation Codes
(NSCNGPIC), Venting Systems and Air Supply for Appliances
Duct Systems
• US and CANADA: Air Conditioning Contractors Association
(ACCA) Manual D, Sheet Metal and Air Conditioning
Contractors National Association (SMACNA), or American
Society of Heating, Refrigeration, and Air Conditioning
Engineers (ASHRAE) Fundamentals Handbook
Electrical Connections
• US: National Electrical Code (NEC) ANSI/NFPA 70
• CANADA: Canadian Electrical Code CSA C22.1
Gas Piping & Gas Pipe Pressure Testing
• US: NFGC and National Plumbing Codes
• CANADA: NSCNGPIC
General Installation
• US: Current edition of the NFGC and the NFPA 90B. For
copies, contact the National Fire Protection Association Inc.,
Batterymarch Park, Quincy, MA 02269; or American Gas
Association, 400 N. Capitol, N.W., Washington DC 20001 or
www.NFPA.org
• CANADA: NSCNGPIC. For a copy, contact Standard Sales,
CSA International, 178 Rexdale Boulevard, Etobicoke
(Toronto), Ontario, M9W 1R3 Canada
Safety
• US: (NFGC) NFPA 54–1999/ANSI Z223.1 and the Installation
Standards, Warm Air Heating and Air Conditioning Systems
ANSI/NFPA 90B.
• CANADA: CAN/CGA-B149.1 and .2–M00 National Standard
of Canada. (NSCNGPIC)
Combustion Air Quality
CAUTION:
Combustion air must not be drawn from a
corrosive atmosphere.
To maximize heat exchanger life, the combustion air must be
free of chemicals that can form corrosive acidic compounds
in the combustion gases. The recommended source of
combustion air is to use outdoor air. However, the use of
indoor air in most applications is acceptable except as listed:
• If the furnace is installed in a confined space, it is required
that the necessary combustion air come from the outdoors
by way of attic, crawl space, air duct, or direct opening.
For installations in confined spaces, see page 7.
• Installations in these locations may require outdoor air for
combustion, due to chemical exposures:
Commercial buildings
Buildings with indoor pools
Furnaces installed in laundry rooms
Furnaces installed in hobby or craft rooms
Furnaces installed near chemical storage areas

5
• Exposure to the following substances in the combustion
air supply may require outdoor air for combustion:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine based swimming pool chemicals
Water softening chemicals
De-icing salts or chemicals
Carbon Tetrachloride
Halogen type refrigerants
Cleaning solvents (perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric Acid
Cements and glues
Antistatic fabric softeners
Masonry acid washing materials
Heating Load
This furnace should be sized to provide the design heating
load requirement. Heating load estimates can be made
using approved methods available from Air Conditioning
Contractors of America (Manual J); American Society of
Heating, Refrigerating, and Air Conditioning Engineers; or
other approved engineering methods. Excessive oversizing
of the furnace could cause the furnace and/or vent to fail
prematurely. The ductwork should be appropriately sized to
the capacity of the furnace to ensure its proper airflow rating.
For installations above 2,000 ft., the furnace should have
a sea level input rating large enough that it will meet the
heating load after deration for altitude.
Two-stage furnaces operate at two input rates to better meet
heating loads. The lower heating rate (low fire) is 65% of the
high fire rate. The greatest degree of control over the furnace
can be gained by controlling it with a two stage thermostat.
This allows the thermostat to directly request either high or
low fire. However, it is possible to operate the furnace using a
single stage thermostat. In this application the furnace control
can be set to increase from low to high fire, based on a timer.
See Autostaging for Single Stage Thermostats (page 23).
Furnaces are properly sized to meet the expected maximum
heating load. But this load occurs infrequently. So, during
more moderate weather, the furnace is likely to use low fire
a considerable part of the time. This is normal and has the
benefit of quieter and more efficient operation.
Installation in a Garage
This Gas-fired furnace may be installed in a residential garage
with the provision that the burners and igniter are located no
less than 18 inches (457mm) above the floor. The furnace
must be located or protected to prevent physical damage
by vehicles.
WARNING:
Do not place combustible material on or against
the furnace cabinet or within 6 inches of the
vent pipe. Do not place combustible materials,
including gasoline or any other flammable vapors
and liquids, in the vicinity of the furnace.
Clearances to Combustible Materials
This furnace is Design Certified in the U.S. and Canada by
CSA International for the minimum clearances to combustible
materials. NOTE: The furnace is listed for installation on
combustible or non-combustible flooring. However, wood is
the only combustible flooring allowed for installation. To obtain
model number and specific clearance information, refer to
the furnace rating plate, located inside of the furnace cabinet.
Access for positioning and servicing the unit must be
considered when locating unit. The need to provide clearance
for access to panels or doors may require clearance distances
over and above the requirements. Allow 24 inches minimum
clearance from the front of the unit. However 36 inches
is strongly recommended. See Figure 1 for minimum
clearance requirements.
Operation of Furnace During Construction
CAUTION:
Operating gas furnaces in construction
environments can cause a variety of problems
within the furnace and may significantly
reduce the life or the performance of the
furnace. Therefore operating the furnace during
construction is not permitted and will void the
warranty.
Figure 1. Minimum Clearances to
Combustible Materials
CLEARANCES TO COMBUSTIBLE MATERIALS
TOP
FRONT
UPFLOW
APPLICATIONS
HORIZONTAL
APPLICATIONS
VENT
SIDE
TOP
BOTTOM
VENT
FRONT
BACK
SIDE
LEFT SIDE
RIGHT SIDE
Left Side ................. 0 Inches Top ..........................0 Inches
Right Side............... 0 Inches Front ........................
†
4 Inches
Vent ........................ 0 Inches Back........................ 0 Inches
†Allow 24 in. minimum clearance for servicing. Recommended clearance
is 36 in.

6
COMBUSTION AIR & VENTING
REQUIREMENTS
WARNING:
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below
for each appliance connected to the venting
system being placed into operation could
result in carbon monoxide poisoning or death.
The following steps shall be followed with
each individual appliance connected to the
venting system being placed in operation,
while all other appliances connected to the
venting system are not in operation:
1.Seal any unused openings in the venting
system.
2.Inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 or the CSA
B149.1, Natural Gas and Propane Installation
Codes and these instructions. Determine that
there is no blockage or restriction, leakage,
corrosion and other deficiencies which could
cause an unsafe condition.
3.As far as practical, close all building doors
and windows and all doors between the space
in which the appliance(s) connected to the
venting system are located and other spaces
of the building.
4.Close fireplace dampers.
5.Turn on clothes dryers and any appliance
not connected to the venting system. Turn on
any exhaust fans, such as range hoods and
bathroom exhausts, so they are operating at
maximum speed. Do not operate a summer
exhaust fan.
6.Follow the lighting instructions. Place the
appliance being inspected into operation.
Adjust the thermostat so appliance is operating
continuously.
7.Test for spillage from draft hood equipped
appliances at the draft hood relief opening
after 5 minutes of main burner operation. Use
the flame of a match or candle.
8.If improper venting is observed during any of
the above tests, the venting system must be
corrected in accordance with the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 and/or CSA
B149.1, Natural Gas and Propane Installation
Codes.
9.After it has been determined that each
appliance connected to the venting system
properly vents when tested as outlined above,
return doors, windows, exhaust fans, fireplace
dampers and any other gas-fired burning
appliance to their previous conditions of use.
IMPORTANT INFORMATION:
• This furnace must be vented in compliance with
the current revision of the National Fuel Gas Code
(ANSI-Z223.1/NFPA54). Instructions for determining
the adequacy of an installation can be found in the
current revision of the NFGC (ANSI Z223.1 / NFPA54).
Consult local codes for special requirements. These
requirements are for US installations as found in the
NFGC.
• Furnace installation using methods other than those
described in the following sections must comply with
the National Fuel Gas Code (NFGC) and all applicable
local codes.
• Requirements in Canada (B149.1) are structured
differently. In Canada, venting shall conform to
the requirements of the current (CAN/CGA B149.1)
installation codes. Consult local codes for special
requirements.
• Provisions must be made during the installation of
this furnace that provide an adequate supply of air
for combustion. The combustion air from the outside
needs to be clear of chemicals that can cause corrosion.
The inlet pipe should not be placed near corrosive
chemicals such as those listed on page 5.
WARNING:
Upon completion of the furnace installation,
carefully inspect the entire flue system both
inside and outside the furnace to assure it is
properly sealed. Leaks in the flue system can
result in serious personal injury or death due
to exposure of flue products, including carbon
monoxide.
WARNING:
This furnace must not be vented with other
appliances, even if that appliance is of the
condensing type. Common venting can result
in severe corrosion of other appliances or their
venting and can allow combustion gases to
escape through such appliances or vents. Do
not vent the furnace to a fireplace chimney or
building chase.
This condensing furnace is certified for installation either as
a Direct Vent (2-pipe) or Conventional (1-pipe) appliance.
Direct Vent appliances draw combustion air from the outdoors
and vent combustion products back outside. Installation
with air taken from around the furnace is often referred to
as Conventional installation - i.e. only the vent (exhaust)
pipe is provided.
Another important consideration when selecting one or
two pipe installation is the quality of the Indoor air which
can sometimes be contaminated with various household
chemicals . These chemicals can cause severe corrosion
in the furnace combustion system. A 2-pipe installation has
the additional advantage that it isolates the system from the
effects of negative pressure in the house.

7
EXAMPLE
If the combined input rate of all appliances is less than or
equal to 100,000 Btuh, each opening must have a free
area of at least 100 in2. If the combined input rate of all
appliances is 120,000 Btuh, each opening must have a
free area of at least 120 in2.
CAUTION:
Exhaust fans, clothes dryers, fireplaces and
other appliances that force air from the house
to the outdoors can create a negative pressure
inside the house, resulting in improper furnace
operation or unsafe conditions such as flame roll
out. It is imperative that sufficient air exchange
with the outdoors is provided to prevent
depressurization. Additional information about
testing negative pressure problems can be found
in the National Fuel Gas Code.
Air openings on top of the furnace and openings in closet
doors or walls must never be restricted. If the furnace is
operated without adequate air for combustion, the flame roll-
out switch will open, turning off the gas supply to the burners.
IMPORTANT NOTE
This safety device is a manually reset switch. DO NOT
install jumper wires across these switches to defeat
their function or reset a switch without identifying
and correcting the fault condition. If a switch must be
replaced, use only the correct sized part specified in the
Replacement Parts List provided online.
Direct Vent Systems
Direct vent appliances draw combustion air from the outdoors
and vent combustion products back outside, isolating the
entire system from the indoor space. It is important to make
sure that the whole system is sealed and clearances to
combustibles are maintained regardless of the installation
being in a confined or unconfined space.
Conventional Vent Systems - Confined Spaces
A confined space is an area with volume less than 50 cubic feet
per 1,000 Btuh of the combined input rates of all appliances
drawing combustion air from that space. Furnace closets,
small equipment rooms and garages are confined spaces.
Furnaces installed in a confined space which supply heated
air to areas outside the space must draw return air from
outside the space and must have the return air ducts tightly
sealed to the furnace. Ducts must have cross - sectional
area at least as large as the free area of their respective
openings to the furnace space. Attics or crawl spaces must
connect freely with the outdoors if they are the source of air
for combustion and ventilation.
The required sizing of these openings is determined by
whether inside or outside air is used to support combustion,
the method by which the air is brought to the space, and by
the total input rate of all appliances in the space. In all cases,
the minimum dimension of any combustion air opening is
3 inches.
Air From Inside
If combustion air is taken from the heated space, the two
openings must each have a free area of at least one square
inch per 1,000 Btuh of total input of all appliances in the
confined space, but not less than 100 square inches of free
area. See Example and Figure 2.
Figure 2. Combustion Air Drawn from Inside
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 100 sq. In 12 inches
60,000 100 sq. In 12 inches
80,000 100 sq. In 12 inches
100,000 100 sq. In 12 inches
120,000 120 sq. In 13 inches
140,000 140 sq. In 14 inches
160,000 160 sq. In 15 inches
Vent or
Chimney
Furnace
Water
Heater
12” Max.
12” Max.
See
Notes
See
Notes
NOTES:
Each opening must be
at least 100 sq. in. or
1 sq. in. per 1,000 Btuh
of total input rating,
whichever is greater.
Openings must start at
no more than 12 inches
from the top and bottom
of the enclosure.
Outdoor Air from a Crawl Space or Vented Attic
When the openings can freely exchange air with the outdoors,
each opening shall have a minimum free area of 1 square
inch per 4,000 Btuh of total appliance input. The openings
shall exchange directly, or by ducts, with the outdoor spaces
(crawl or attic) that freely exchange with the outdoors. See
Figure 3.
Water
Heater
Vent or
Chimney
- - - - - - - - -
- - - - - - - - -
Furnace
Ventilation Louvers For
Unheated Crawl Space
- - - - - - - - -
Inlet Air
Ventilation Louvers
(each end of attic)
NOTE: Air openings shall
each have a free area of
not less than one square
inch per 4,000 Btuh of the
total input rating of all
equipment in the enclosure
.
- - - - - - - - -
Alter
nate
Air Inlet
Outlet
Air
Figure 3. Combustion Air Drawn from a Crawl
Space or Vented Attic

8
Outdoor Air Using Vertical Ducts
If combustion air is taken from outdoors through vertical
ducts, the openings and ducts must have a minimum free
area of one square inch per 4,000 Btuh of total appliance
input. See Figure 4.
Outdoor Air Using Horizontal Ducts
If combustion air is taken from outdoors through horizontal
ducts, the openings and ducts must have a minimum free
area of one square inch per 2,000 Btuh of total appliance
input. Ducts must have cross - sectional area at least as
large as the free area of their respective openings to the
furnace space. See Figure 5.
Air Directly Through an Exterior Wall
If combustion air is provided directly through an exterior
wall, the two openings must each have free area of at least
one square inch per 4,000 Btuh of total appliance input.
See Figure 6.
Alternate Method of Providing Air from Outside:
If acceptable under local Codes, it is permitted to provide
outside air using one opening (See NFGC). Generally,
confined spaces must have 2 openings in the space for
combustion air. One opening must be within 12 inches of
the ceiling, and the other must be within 12 inches of the
floor. However, an alternative method recently adopted by
the NFGC uses one opening within 12 inches of the top of
the space. This method may be used if it is acceptable to
the local codes.
THE FOLLOWING CONDITIONS MUST BE MET:
1. The opening must start within 12” of the top of the structure
and connect with the out of doors through vertical or
horizontal ducts or be ducted to a crawl or attic space that
connects with the out of doors.
Figure 4. Combustion Air Drawn from Outside
Through Vertical Ducts
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 10 sq. In 4 inches
60,000 15 sq. In 5 inches
80,000 20 sq. In 5 inches
100,000 25 sq. In 6 inches
120,000 30 sq. In 6 inches
140,000 35 sq. In 7 inches
160,000 40 sq. In 8 inches
Air Duct must be
at least 1 sq. in.
per 4,000 Btuh of
total input rating.
Ducts must
extend above
attic insulation.
Air Duct must be
at least 1 sq. in.
per 4,000 Btuh of
total input rating.
Ventilation Louvers
at each end of attic
Attic
Insulation
12" Max
Furnace
Water
Heater
Vent or
Chimney
Figure 5. Combustion Air Drawn from Outside
Through Horizontal Ducts
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 20 sq. In 5 inches
60,000 30 sq. In 6 inches
80,000 40 sq. In 7 inches
100,000 50 sq. In 8 inches
120,000 60 sq. In 9 inches
140,000 70 sq. In 10 inches
160,000 80 sq. In 10 inches
Furnace
Water
Heater
Air Ducts must be
at least 1 sq. in.
per 2,000 Btuh of
total input rating.
Vent or
Chimney
Air Duct
Air Duct
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 10 sq. In 4 inches
60,000 15 sq. In 5 inches
80,000 20 sq. In 5 inches
100,000 25 sq. In 6 inches
120,000 30 sq. In 6 inches
140,000 35 sq. In 7 inches
160,000 40 sq. In 8 inches
NOTE:
Each opening to outside
must be at least 1 sq. in. per
4,000 Btuh of total input rating.
12" Max.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Furnace
Water
Heater
Vent or
Chimney
12"
Max
See
Note
See
Note
Figure 6. Combustion Air Drawn from Outside
Through an Exterior Wall
2. The opening must have a minimum free area of 1 in2. per
3,000 Btu per hour of the total input rating of all equipment
located in the enclosure.
3. The free area must not be less than the sum of all the
areas of the vent connectors in the enclosure.

9
Conventional Vent Systems - Unconfined
Spaces
An unconfined space is an area including all rooms not
separated by doors with a volume greater than 50 cubic feet
per 1,000 Btuh of the combined input rates of all appliances
which draw combustion air from that space.
In general, a furnace installed in an unconfined space will
not require outside air for combustion. However, in homes
built for energy efficiency (low air change rates), it may
be necessary to provide outside air to ensure adequate
combustion and venting, even though the furnace is located
in an unconfined space. See Example below.
EXAMPLE
A space with a water heater rated at 45,000 Btuh input
and a furnace rated at 75,000 Btuh requires a volume of
6,000 cubic feet [50 x (45 + 75) = 6,000] to be considered
unconfined. If the space has an 8 foot ceiling, the floor
area of the space must be 750 sq. ft. (6,000 / 8 = 750).
Category IV Venting
WARNING:
Upon completion of the furnace installation,
carefully inspect the entire flue system both
inside and outside the furnace to assure it is
properly sealed. Leaks in the flue system can
result in serious personal injury or death due
to exposure of flue products, including carbon
monoxide.
This furnace is classified as a “Category IV” appliance,
which requires special venting materials and installation
procedures. This section specifies installation requirements
for Conventional (1-pipe) and Direct Vent (2-pipe) piping.
For 1- pipe installations, install vent piping as described in
this section and provide air for combustion and ventilation
according to the Combustion Air & Venting Requirements
section (page 6). The length of vent and combustion air
piping for either type of installation are shown in Table 1.
Category IV appliances operate with positive vent pressure
and therefore require vent systems which are thoroughly
sealed. They also produce liquid condensate, which is slightly
acidic and can cause severe corrosion of ordinary venting
materials. Furnace operation can be adversely affected by
restrictive vent and combustion air piping.
The inducer assembly on this furnace can be rotated to vent
the flue products out of the left or right side of the furnace.
This increases the flexibility of which direction the vent pipe
can exit the furnace.
Vent Pipe Material
Vent and combustion air pipe and fittings must be one of
the following materials in the list and must conform to the
indicated ANSI/ASTM standards.
MATERIALS STANDARDS
Schedule 40PVC ......................................................D1785
CPVC........................................................................D1784
PVC-DWV.................................................................D2665
SDR-21 & SDR-26....................................................D2241
ABS-DWV.................................................................D2661
Schedule 40 ABS .....................................................F628
Foam / Cellular Core PVC........................................F891
*PolyPro®by DuraVent .............................................ULC-S636
*InnoFlue®by Centrotherm.................UL1738 and ULC-S636
*When using PolyPro®or InnoFlue®, all venting and fittings must be from
the same manufacturer with no interchanging of other materials. Refer
to specific instructions supplied with the PolyPro and InnoFlue vent kits.
When joining PVC to PVC, use cement that conforms to
ASTM standard D2564. PVC primer must meet standard
ASTM F656. When joining ABS to ABS, use cement that
conforms to ASTM standard D2235. When joining PVC
to ABS, use cement as specified in procedure from ASTM
standard D3138.
In Canada, all plastic vent pipes and fittings including any
cement, cleaners, or primers must be certified as a system
to ULC S636. However this requirement does not apply to
the finish flanges or piping internal to the furnace.
Table 1. Vent Pipe Lengths
FURNACE
MODELS
(BTU)
FURNACE
INSTALLATION
SINGLE VENT PIPE LENGTH (FT.)
WITH 1 LONG RADIUS ELBOW*
DUAL VENT PIPE LENGTH (FT.)
WITH 1 LONG RADIUS ELBOW ON EACH PIPE*
OUTLET
2” DIAMETER
OUTLET
3” DIAMETER
INLET / OUTLET
2” DIAMETER
INLET / OUTLET
3” DIAMETER
38,000 Upflow 90 90 90 90
Horizontal 50 90 50 90
60,000 Upflow 90 90 90 90
Horizontal 50 90 50 90
80,000 Upflow 40 90 40 90
Horizontal 30 90 30 90
100,000 Upflow 30 90 30 90
Horizontal 30 90 30 90
120,000 Upflow N/A 90 N/A 90
Horizontal N/A 90 N/A 90
*NOTES:
1. Subtract 2.5 ft. for each additional 2 inch long radius elbow, 5 ft. for each additional 2 inch short radius elbow, 3.5 ft. for each additional 3 inch
long radius elbow, and 7 ft. for each additional 3 inch short radius elbow. Subtract 5 ft for each 2” tee and 8 ft for each 3” tee. Two 45 degree
elbows are equivalent to one 90 degree elbow.
2. This table applies for elevations from sea level to 2,000 ft. For higher elevations, decrease pipe lengths by 8% per 1,000 ft of altitude.

10
Vent Pipe Length & Diameter
In order for the furnace to operate properly, the combustion
air and vent piping must not be excessively restrictive.
• The venting system should be designed to have the
minimum number of elbows or turns.
• Transition to the final vent diameter should be done as
close to the furnace outlet as practical.
• Always use the same size or a larger pipe for combustion
air that is used for the exhaust vent.
Table 1 indicates the maximum allowable pipe length for a
furnace of known input rate, when installed with piping of
selected diameter and number of elbows. To use the table,
the furnace input rate, the centerline length and the number
of elbows on each pipe must be known.
When estimating the length of vent runs, consideration must
be made to the effect of elbows and other fittings. This is
conveniently handled using the idea of “equivalent length”.
This means the fittings are assigned a linear length that
accounts for the pressure drop they will cause. For example:
a 2” diameter, long radius elbow is worth the equivalent of
2.5 feet of linear run. A 90 degree tee is worth 7 ft.
The equivalent lengths of tees and various elbows are listed
in Table 1 . Measure the linear length of the vent run and
then add in the equivalent length of each fitting. The total
length, including the equivalent fitting lengths, must be less
than the maximum length specified in Table 1.
Vent Pipe Installation
CAUTION:
Combustion air must not be drawn from a
corrosive atmosphere.
This furnace has been certified for installation with zero
clearance between vent piping and combustible surfaces.
However, it is good practice to allow space for convenience
in installation and service.
• In the absence of local codes, the location of any combustion
air inlet relative to any vent terminal must be at least 8
inches. This includes installations involving more than one
furnace.
• The quality of outdoor air must also be considered. Be
sure that the combustion air intake is not located near
a source of solvent fumes or other chemicals which can
cause corrosion of the furnace combustion system. (See
list of substances on page 5).
• Route piping as direct as possible between the furnace
and the outdoors. Horizontal piping from inducer to the flue
pipe must be sloped 1/4” per foot to ensure condensate
flows towards the drain tee or PVC trap. Longer vent runs
require larger pipe diameters. Refer to the Inducer & Venting
Options section on page 15 for additional information.
• If a Direct Vent (2-pipe) system is used, the combustion air
intake and the vent exhaust must be located in the same
atmospheric pressure zone. This means both pipes must
exit the building through the same portion of exterior wall
or roof as shown in Figure 7, Figure 8,Figure 9,&Figure
10 (page 11).
• Piping must be mechanically supported so that its weight
does not bear on the furnace. Pipe supports must be
installed a minimum of every 5 feet along the vent run to
Figure 9. Alternate Horizontal Vent Installation
Support
NOTE: Vent Configuration to Provide
12" Minimum height above Snow Level.
1/2"
Armaflex
Insulation or
Equivalent
(if required)
12" Above
Maximum
Expected
Snow Level
19" Max.
(See Note)
Outside
Wall
12” min. to maximum
expected snow level
(both pipes)
90° Elbow
Exhaust vent
option B
Exhaust vent
option A
Mounting kit faceplate
secured to wall with screws
(both pipes)
Combustion
air inlet
Exhaust vent
option C
18” Min.18” Min.
36” Max.36” Max.
8” Min.
36” Max.
(all positions)
Figure 7. Inlet & Exhaust Pipe Clearances
Note 2
Mechanical draft
vent terminal
Direct vent
terminal
50,000 Btuh
or less
Forced air inlet
Direct vent
terminal - more
than 50,000 Btuh
Mechanical
draft vent
terminal
Mechanical
draft vent
terminal
Less
than
10 ft.
3 ft.
NOTES:
1. All dimensions shown are
minimum requirements.
2. Exterior vent terminations must
be located at least 12” above the
maximum expected snow level.
Note 2
4 ft
4 ft
12 in.
12 in.
9 in.
Note 2
Figure 8. Vent Locations

11
ensure no displacement after installation. Supports may be
at shorter intervals if necessary to ensure that there are no
sagging sections that can trap condensate. See Figure 32
(page 35)and Figure 33 (page 36). It is recommended
to install couplings along the vent pipe, on either side of
the exterior wall. These couplings may be required by local
code.
• If breakable connections are required in the combustion air
inlet pipe (if present) and exhaust vent piping, then straight
neoprene couplings for 2” or 3” piping with hose clamps
can be used. These couplings can be ordered through
your local furnace distributor. To install a coupling:
1. Slide the rubber coupling over the end of the pipe that is
attached to the furnace and secure it with one of the hose
clamps.
2. Slide the other end of the rubber coupling onto the other
pipe from the vent.
3. Secure the coupling with the second hose clamp, ensuring
that the connection is tight and leak free.
Outdoor Terminations - Horizontal Venting
• Vent and combustion air intake terminations shall be
installed as depicted in Figure 7 & Figure 8 and in accordance
with these instructions:
• Vent termination clearances must be consistent with the
NFGC, ANSI 2223.1/NFPA 54 and/or the CSA B149.1,
Natural Gas and Propane Installation Code. Table 11
(page 34) lists the necessary distances from the vent
termination to windows and building air intakes.
• Vent and combustion air intake terminations must be located
to ensure proper furnace operation and conformance to
applicable codes. A vent terminal must be located at least
3 feet above any forced air inlet located within 10 feet.
This does not apply to the combustion air inlet of a direct
vent (two pipe) appliance. In Canada, CSA B149.1, takes
precedence over these instructions. See Table 11.
• All minimum clearances must be maintained to protect
building materials from degradation by flue gases. See
Figure 7.
• For optimal performance, vent the furnace through a wall
that experiences the least exposure to winter winds.
• The vent termination shall be located at least 3 ft. horizontally
from any electric meter, gas meter, regulator and any
relief equipment. These distances apply ONLY to U.S.
installations. In Canada, CSA B149.1, takes precedence
over these instructions.
• Do not install the vent terminal such that exhaust is directed
into window wells, stairwells, under decks or into alcoves
or similar recessed areas, and do not terminate above any
public walkways.
Figure 10. Vertical Vent Termination
Combustion Air
Exhaust Vent
12” Above Maximum
Expected Snow Level
(Both pipes)
Elbows on the combustion air
inlet must be positioned pointing
away from the exhaust vent.
8" Min.
36" Max.
Plumbing Vent Roof Boot
(Both Pipes)
• If venting horizontally, a side wall vent kit is available
according to the pipe diameter size of the installation. For
2 inch pipe use side wall vent kit #904617, and for 3 inch
pipe use kit #904347. Please follow the instructions
provided with the kit.
• Concentric vent kits are available for both 2” and 3”
applications. Each size has one that meets UL 1738 and
one that meets ULC S636. Refer to the technical sales
literature for kit numbers.
• When the vent pipe must exit an exterior wall close to the
grade or expected snow level where it is not possible to
obtain clearances shown in Figure 7 (page 10), a riser may
be provided as shown in Figure 9 (page 10). Insulation
is required to prevent freezing of this section of pipe. See
Table 2 for vent freezing protection.
Outdoor Terminations - Vertical Venting
Termination spacing requirements from the roof and from
each other are shown in Figure 10. The roof penetration must
be properly flashed and waterproofed with a plumbing roof
boot or equivalent flashing. Vent and combustion air piping
may be installed in an existing chimney which is not in use
provided that:
• Both the exhaust vent and air intake run the length of the
chimney.
• The top of the chimney is sealed and weatherproofed.
• The termination clearances shown in Figure 10 are
maintained.
• No other gas fired or fuel-burning equipment is vented
through the chimney.
Vent Freezing Protection
CAUTION:
When the vent pipe is exposed to temperatures
below freezing (i.e., when it passes through
unheated spaces, chimneys, etc.) the pipe
must be insulated with 1/2 inch thick sponge
rubber insulation, Armaflex-type insulation or
equivalent. Insulating pipe is important to avoid
condensate icing.
• Table 2 lists the maximum length of flue pipe that can travel
through an unconditioned space or an exterior space. The
total vent length must not exceed the lengths noted in Table
1 (page 9). For Canadian installations, please refer to
the Canadian Installation Code (CAN/CGA-B149.1) and/
or local codes.
• For extremely cold climates or for conditions of short
furnace cycles (i.e. set back thermostat conditions) the last
WINTER DESIGN
TEMPERATURE
MAXIMUM FLUE PIPE LENGTH (FEET)
IN UNCONDITIONED & EXTERIOR SPACES
WITHOUT INSULATION WITH INSULATION*
20 45 70
0 20 70
-20 10 60
*NOTE: Insulation thickness greater than 3/8 inch, based on an
R value of 3.5 (ft x F x hr) / (BTU x in.)
Table 2. Vent Protection

12
18 inches of vent pipe can be reduced. It is acceptable
to reduce from 3” to 2-1/2”, 3” to 2”, or 2” to 1-1/2” if the
total vent length is at least 15 feet in length and the vent
length is within the parameters specified in Table 1. The
restriction should be counted as 3 equivalent feet. Smaller
vent pipes are less susceptible to freezing, but must not
be excessively restrictive. The length of the 2 inch pipe
must not be longer than 18 inches.
• If furnace is installed horizontally, make sure the drainage
port on the in-line drain assembly is pointed downward
to ensure proper drainage of condensate. See Figure 36
(page 39)& Figure 37 (page 40).
• To prevent debris or creatures from entering the combustion
system, a protective screen may be installed over the
combustion air intake opening. The screens hole size
must be large enough to prevent air restriction.
Existing Installations
When an existing furnace is removed from a vent system
serving other appliances, the existing vent system may not
be sized properly to vent the remaining appliances (For
example: water heater). An improperly sized venting system
can result in the formation of condensate, leakage, or spillage.
The existing vent system should be checked to make sure
it is in compliance with NFGC and must be brought into
compliance before installing the furnace.
NOTE: If replacing an existing furnace, it is possible you will
encounter an existing plastic venting system that is subject
to a Consumer Product Safety Commission recall. The pipes
involved in the recall are High Temperature Plastic Vent
(HTPV). If your venting system contains these pipes DO
NOT reuse this venting system! This recall does not apply
to other plastic vent pipes, such as white PVC or CPVC.
Check for details on the CPSC website or call their toll-free
number [phone].
Condensate Disposal
The method for disposing of condensate varies according
to local codes. Consult your local code or authority having
jurisdiction.
Each of the condensate drain lines must be J-trapped using
field supplied parts. After the condensate lines are J-trapped,
they may be combined together into a single run to the drain.
The drain lines must be routed downward to ensure proper
drainage from furnace.
Neutralizer kit P/N 902377 is available for use with this furnace.
Please follow the instructions provided with the kit.
For Installations where there is limited clearance for the
J-Trap (such as an attic where it may be installed between
ceiling joists), either side of the J-Trap can be shortened to
a minimum of 3 Inches. See Figure 11, (page 14).
CIRCULATING AIR REQUIREMENTS
WARNING:
Do not allow combustion products to enter the
circulating air supply. Failure to prevent the
circulation of combustion products into the
living space can create potentially hazardous
conditions including carbon monoxide poisoning
that could result in personal injury or death.
All return ductwork must be secured to the
furnace with sheet metal screws. For installations
in confined spaces, all return ductwork must be
adequately sealed. When return air is provided
through the bottom of the furnace, the joint
between the furnace and the return air plenum
must be air tight.
The surface that the furnace is mounted on must
provide sound physical support of the furnace
with no gaps, cracks or sagging between the
furnace and the floor or platform.
Return air and circulating air ductwork must
not be connected to any other heat producing
device such as a fireplace insert, stove, etc. This
may result in fire, explosion, carbon monoxide
poisoning, personal injury, or property damage.
Plenums & Air Ducts
• Plenums and air ducts must be installed in accordance with
the Standard for the Installation of Air Conditioning and
Ventilating Systems (NFPA No. 90A) or the Standard for
the Installation of Warm Air Heating and Air Conditioning
Systems (NFPA No. 90B).
• If the maximum airflow is 1,600 CFM or more, it is required
that two openings be used for return air on upflow furnaces.
• It is recommended that the outlet duct contain a removable
access panel. The opening should be accessible when the
furnace is installed in service and shall be of a size that
smoke or reflected light may be observed inside the casing
to indicate the presence of leaks in the heat exchanger.
The cover for the opening shall be attached in such a way
as to prevent leaks.
• If outside air is used as return air to the furnace for
ventilation or to improve indoor air quality, the system must
be designed so that the return air is not less than 60° F
(15° C) during operation. If a combination of indoor and
outdoor air is used, the ducts and damper system must
be designed so that the return air supply to the furnace is
equal to the return air supply under normal, indoor return
air applications.
• When a cooling system is installed which uses the furnace
blower to provide airflow over the indoor coil, the coil must
be installed downstream (on the outlet side) of the furnace
or in parallel with the furnace.
• If a cooling system is installed in parallel with the furnace, a
damper must be installed to prevent chilled air from entering
the furnace and condensing on the heat exchanger. If a
manually operated damper is installed, it must be designed
so that operation of the furnace is prevented when the

13
damper is in the cooling position and operation of the
cooling system is prevented when the damper is in the
heating position.
• It is good practice to seal all connections and joints with
industrial grade sealing tape or liquid sealant. Requirements
for sealing ductwork vary from region to region. Consult
with local codes for requirements specific to your area.
Return Air Connections
• In applications where the supply ducts carry heated air to
areas outside the space where the furnace is installed,
the return air must be delivered to the furnace by duct(s)
secured to the furnace casing, running full size and without
interruption. Do not use the back of the furnace for
return air.
• Position the furnace with the return air ductwork ensuring
even alignment of furnace (or coil casing) air opening and
return air duct. NOTE: The ductwork must have an opening
equal to that of the return air opening of the furnace (or coil
casing). See Figure 26 (page 27)for return air opening
size.
Upflow & Horizontal Furnaces
• The return air ductwork may be connected to the left side,
right side, or bottom of the furnace. NOTE: If using the left
or right side of the furnace for return air, the bottom panel
(Figure 26) must not be removed from the bottom of the
furnace.
WARNING:
The bottom panel of the furnace must be in
place when the furnace is installed with side
return air ducts. Removal of all or part of the
base could cause circulation of combustible
products into the living space and create
potentially hazardous conditions, including
carbon monoxide poisoning that could result in
personal injury or death.
• Side Return Installations: To attach the return air duct
to the left or right side of the furnace, punch out the 4
knockouts from the side of the furnace (Figure 26 (page
27)). Using sharp metal cutters, cut an opening between
all 4 knockouts to expose the blower assembly. Position
the return air duct over the opening and secure to the side
with sheet metal screws.
• Bottom Return Installations: If using the bottom of the
furnace for return air, the bottom panel (Figure 26) must be
removed from the bottom of the furnace. See page 17 for
removal instructions. Position the furnace over the return
air duct and secure together with sheet metal screws. Make
sure the screws penetrate the duct and furnace casing.
Supply Air Connections
• The supply air must be delivered to the heated space by
duct(s) secured to the furnace or coil box casing, running
full size and without interruption.
• To attach the supply air duct to upflow & horizontal furnaces,
bend the flanges on the furnace upward 90° with wide
duct pliers. See Figure 26 (page 27)for furnace flange
locations. NOTE: If system installation includes AC coil
casing, bend the flanges on the coil casing upward 90°
before attaching the supply air duct.
• Position the supply air ductwork onto the furnace ensuring
even alignment of furnace air opening and supply air duct.
NOTE: The ductwork must have an opening equal to that
of the supply air opening of the furnace. See Figure 26 for
supply air opening size.
Acoustical Treatments
Damping ducts, flexible vibration isolators, or pleated media-
style filters on the return air inlet of the furnace may be used
to reduce the transmission of equipment noise eminating
from the furnace. These treatments can produce a quieter
installation, particularly in the heated space. However, they
can increase the pressure drop in the duct system. Care
must be taken to maintain the proper maximum pressure rise
across the furnace, temperature rise and flow rate. This may
mean increasing the duct size and/or reducing the blower
speed. These treatments must be constructed and installed in
accordance with NFPA and SMACNA construction standards.
Consult with local codes for special requirements. For best
sound performance, be sure to install all the needed gaskets
and grommets around penetrations into the furnace, such
as for electrical wiring

14
FURNACE INSTALLATION
*TC series gas furnaces offer a wide range of installation
options, including installation in the upflow or horizontal
positions with either right, left, or upflow return air.
General Requirements
• The furnace must be leveled at installation and attached to
a properly installed duct system. See Figure 1 (page 5)
for the required clearances needed to move the furnace
to its installation point (hallways, doorways, stairs, etc).
• The furnace must be installed so that all electrical
components are protected from water.
• The furnace must be installed upstream from a refrigeration
system. (If applicable)
• The cabinet plug must always be used to close the hole
in the side of the furnace when rotating the inducer.
• The furnace requires special venting materials and
installation procedures. Refer to the Combustion Air &
Venting Requirements section (page 6) for venting
guidelines and specifications.
Upflow Furnaces
WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.
*TC series gas furnaces are shipped with the bottom panel
installed as shown in Figure 16 (page 18). If the furnace
is installed with only side return air, the bottom panel must
not be removed. If the furnace is installed with bottom return
air, the bottom panel must be removed. See Bottom Panel
Removal on page 17.
Horizontal Furnaces
WARNING:
The furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.
The *TC series gas furnace can be installed horizontally
(Figure 11) in an attic, basement, crawl space or alcove. It
can also be suspended from a ceiling in a basement or utility
room in either a right to left airflow or left to right airflow as
shown in Figure 12.
*TC series furnaces are shipped with the bottom panel
installed. If furnace is installed horizontally, remove the bottom
panel from the furnace before attaching the duct system. See
Bottom Panel Removal section (page 17).
If installing the furnace with an evaporator coil (in an
attic), it is required that a drip pan be placed under the
furnace. If the installation is on a combustible platform
(Figure 11), it is recommended that the drip pan extend
at least 12 inches past the top and front of the furnace.
NOTE: Although it is not required to use a drip pan for heat
only applications, state and local codes may require it.
If the furnace will be suspended from the ceiling, assemble a
support frame (Figure 12) using slotted iron channel and full
threaded rod. Fasten the frame together with nuts, washers,
and lockwashers. Secure the support frame to the rafters
with lag bolts.
NOTE: The furnace can also be suspended using steel
straps around each end of the furnace. The straps should
be attached to the furnace with sheet metal screws and to
the rafters with bolts.
It is recommended for further reduction of fire hazard that
cement board or sheet metal be placed between the furnace
and the combustible floor and extend 12 inches beyond the
front of the door and top of the furnace.
Figure 12. *TC Horizontally Suspended in Attic
Lag
Bolt
Nuts (x2)
Washer
and
Lockwasher
Nuts (x2)
Threaded
Rod
Flue pipe vented
to outside
J-Trap
Height
3” Min.
Coil Plenum
Wood or
non-combustible
platform
Combustion Air Condensate
Drain Lines
Figure 11. *TC Horizontally Installed on a Platform

15
Inducer & Venting Options
To increase installation flexibility, the inducer assembly can be
rotated to 2 different positions (‘B’, ‘C’, & ‘D’ width cabinets
only). Each variation has slightly different requirements with
regard to condensate disposal and, in some cases, the need
to seal the furnace cabinet.
IMPORTANT NOTES
• For ‘A’ width cabinets, the vent pipe can only exit the
cabinet through the top of the cabinet.
• The inducer assembly must never be positioned to
vent downwards on horizontal installs.
Before using Table 3,the number of pipes (1-pipe or 2-pipe)
connected to the furnace must be known. Find the proper
furnace style (upflow or horizontal) and then the side that
the pipes will exit from the furnace. Finally select the option
that properly matches your installation type from Figure 34
(page 37), Figure 35 (page 38), Figure 36 (page 39)&
Figure 37 (page 40).
NOTE: It is important that Direct Vent (2-pipe) systems
maintain an airtight flow path from the air inlet to the flue
gas outlet. The furnace ships from the factory with two holes
in the cabinet for the air inlet and flue gas outlet. In certain
configurations, it is necessary to remove and relocate a
plastic cap in the furnace cabinet. If changing the position
of the air inlet and flue gas outlet, it is required that the
previous hole be closed off with the plastic cap to maintain
air tightness in the furnace. The hole locations are shown
in Figure 26 (page 27).
Inducer Assembly Rotation
WARNING:
Inducer rotation must be completed before
the furnace is connected to gas and electric. If
both utilities have been connected, follow the
shutdown procedures printed on the furnace
label and disconnect the electrical supply.
CAUTION:
It is good practice to label all wires prior to
disconnection. Wiring errors can cause improper
and dangerous operation.
1. Disconnect the electrical harness from the inducer
assembly.
2. Remove the inducer assembly ground wire from the blower
deck or door.
3. Remove 4 screws securing the inducer assembly to the
header box.
4. Remove drain tube from inline drain assembly.
5. Rotate the inducer assembly to its new position.
6. Secure the inducer assembly to the header box by
reinstalling the four screws.
7. Remove the cabinet plug from side of furnace and reinstall
in hole on opposite side of cabinet.
8. Connect all condensate drains as required for your
installation. See Table 3 and Figure 34 (page 37), Figure
35 (page 38), Figure 36 (page 39)or Figure 37 (page
40).
9. Reconnect the electrical harness to the inducer assembly.
10. Reconnect the inducer assembly ground wire to the blower
deck or door.
11.Verify proper operation as detailed on the furnace label.
Pressure Switch Tubing
Figure 13 displays the proper routing of pressure switch tubing
for *TC furnaces. All upflow / horizontal furnaces have two
pairs of switches. One set is connected to the static tap on
the inducer assembly and the other to the collector box.
‘A’ WIDTH CABINETS
VENT UPFLOW HORIZ.
RIGHT
HORIZ.
LEFT
1-Pipe
Options
Right N/A Option 7 N/A
Up Option 1 N/A N/A
Left N/A N/A Option 8
2-pipe
Options
Right N/A Option 9 N/A
Up Option 2 N/A N/A
Left N/A N/A Option 10
B, C, & D, WIDTH CABINETS
VENT UPFLOW HORIZ.
RIGHT
HORIZ.
LEFT
1-Pipe
Options
Right Option 3 N/A N/A
Up N/A Option 11 Option 12
Left Option 4 N/A N/A
2-pipe
Options
Right Option 5 N/A N/A
Up N/A Option 13 Option 14
Left Option 6 N/A N/A
Table 3. Vent & Inducer Blower Options
AIRFLOW
12345678
Figure 13. Pressure Switch Tubing for
*TC Upflow / Horizontal Furnaces
*Not applicable for ‘A’ Width Cabinets

16
Accessories
The components in Figure 14 & Figure 15 are included in the
extra parts bag supplied with the purchase of *TC furnaces.
Depending on your particular installation, some of these
components are optional and may not be used. Please refer
to the descriptions and accompanying figures when installing
these items.
Finish Flange
The finish flange must be installed to vent the combustion
air pipe through the top of the furnace. NOTE: For proper
installation it is important that the pipe and screw holes in
the finish flange, gasket, and cabinet are aligned.
1. Position flange gasket over hole in the furnace cabinet.
2. Position finish flange on top of the flange gasket.
NOTE: Make sure the flange is properly oriented so that
the FRONT lettering is located near the front of the furnace
as shown in Figure 14.
3. Secure flange and gasket to cabinet with three field supplied
sheet metal screws.
Rubber Grommets
The 2 1/4” rubber grommet is used to seal the opening
between the furnace cabinet and the 2” PVC vent pipe. The
rubber grommet should be installed in the 3” hole prior to
running the vent pipe out of cabinet. No sealants are required.
See Figure 14.
The 7/8” rubber grommet is used to seal the opening between
the furnace cabinet and the gas pipe. The rubber grommet
should be installed in the 1 5/8” hole prior to running the gas
pipe into the cabinet. No sealants are required.
The 3/4” rubber grommet is used if venting out the left side of
the cabinet and the drain tube is routed through the blower
deck. Remove the plastic plug from the hole and install the
grommet before routing the drain tube.
PVC Components
IMPORTANT NOTES:
• Before permanently installing these components, it is
recommended you dry-fit them first to ensure proper
fit and alignment with other vent pipes.
• The 2” PVC pipe shown in Figure 15 is not provided in
the extra parts bag.
The 2” PVC Tee and Trap are used when the inducer is
rotated to vent out thru the left or right side of the furnace
cabinet. See Figure 15.
The 1/2” x 3/4” hose barb can be used to route the condensate
drain to the outside of the cabinet. It must be installed from
inside the cabinet with the threaded end inserted thru the 1
1/16” hole. See Figure 26 (page 27)for hole location. The
condensate drain should be connected to the barbed end.
Attach 1” PVC drain line to the threaded end.
Typical Orientation
1. Install the PVC Tee vertically on the 2” vent pipe that is
extending out the side of the cabinet. Permanently bond
them together using appropriate primer and cement. Refer
to the typical orientation shown in Figure 15.
2. Install the reducer or PVC trap (if supplied) on the bottom
end of the PVC Tee. Permanently bond them together
using appropriate primer and cement.
Figure 15. PVC Components
Ø 3/4” Rubber
Grommet
ø 2 1/4” Rubber
Grommet
ø 7/8” Rubber
Grommet
Inlet Air
Finish Flange
Flange
Gasket
FRONT
FRONT lettering must be
located near front
of furnace
1/2” x 3/4”
Hose Barb
2” PVC Elbow
(Field Supplied)
2” PVC Te e
1/2” x 3/4”
Hose Barb
2” PVC Pipe from Inline
Drain Assembly
(Not Included)
PVC
Trap
INSTALLATION OF PVC COMPONENTS
(TYPICAL ORIENTATION)
INSTALLATION OF PVC COMPONENTS
(ALTERNATE ORIENTATION)
2” PVC Te e
2” PVC Pipe from Inline
Drain Assembly
(Not Included)
PVC
Trap
1/2” Tubing (Field Supplied
)
Drain Line Attached
to PVC Tr ap
(Do Not Tr ap)
1/2” Tubing (Field Supplied)
Drain Line Attached
to PVC Tr ap
(Do Not Tr ap)
Figure 14. Finish Flange & Rubber Grommets

17
3. Install the 1/2” x 1/2” hose barb on the 2” PVC reducer.
NOTE: Do not over tighten! Use an adequate amount of
Teflon tape on the threads. Do not use liquid sealants.
4. Verify all connections and joints for tight fit and proper
alignment with other vent pipes.
Alternate Orientation
1. Install the 2” PVC Tee horizontally on the 2” vent pipe that
is extending out the side of the cabinet. Permanently bond
them together using appropriate primer and cement. Refer
to the alternate orientation shown in Figure 15.
2. Install the 2” PVC Elbow on the end of the 2” PVC Tee.
Permanently bond them together using appropriate primer
and cement.
3. Install the reducer or PVC trap (if supplied) on the bottom
end of the PVC Tee. Permanently bond them together
using appropriate primer and cement.
4. Install the 1/2” x 1/2” hose barb on the 2” PVC reducer.
NOTE: Do not over tighten! Use an adequate amount of
Teflon tape on the threads. Do not use liquid sealants.
5. Verify all connections and joints for tight fit and proper
alignment with other vent pipes.
Condensate Drain Lines
IMPORTANT NOTE
If the furnace is installed in an area where temperatures
fall below freezing, special precautions must be made
for insulating condensate drain lines that drain to the
outdoors. If condensate freezes in the lines, this will
cause improper operation or damage to the furnace. It
is recommended that all drain lines on the outside of
the residence be wrapped with an industry approved
insulation or material allowed by local code.
The placement of the condensate drain lines will depend on
the configuration selected in Table 3 (page 15). The drain
lines can be routed out the left or right side of the furnace,
but must maintain a downward slope to ensure proper
condensate drainage.
The J-trap may need to be rotated to the side that matches
your setup in Figure 34 (page 37), Figure 35 (page 38),
Figure 36 (page 39)& Figure 37 (page 40). To rotate the
J-trap, loosen the clamp on the drain tube, rotate the J-trap
to either side, and retighten the clamp.
It is permissible to locate the trap away from the furnace. The
condensate drain system (J-trap and drain tube) should be
no more than 30 equivalent feet while maintaining 1/4” per
foot slope, and insulated if located in an unconditioned space.
THREE GENERAL RULES APPLY:
• Each condensate drain line must be separately trapped
using a J-Trap or field supplied loop. After individually
trapping the condensate lines, it is acceptable to combine
the drains.
• There must always be a drain attached to the collector at
the outlet of the secondary heat exchanger.
• There must always be a drain at the lowest point of the
venting system. NOTE: If using a condensate pump, the
furnace drain line must be installed above the pumps water
line.
EXCEPTIONS AND CLARIFICATIONS TO THE
GENERAL RULES:
• In some cases, the lowest point in the vent system is where
it connects to the inducer (Option 12 & Option 14). In this
case one drain at this location is sufficient.
• If the vent exits the furnace horizontally, the vent may be
turned vertically with a tee. The drip leg formed by the
tee must include a drain (Option 3, Option 4, Option 5, &
Option 6).
• In certain cases, it is permitted to drain the inducer back
into the top drain of the collector (Option 3, Option 5, Option
11, & Option 13). To ensure proper drainage of condensate,
make sure the drain line does not sag or becomes twisted.
The drain tube supplied with the furnace may need to be
trimmed.
Bottom Panel Removal
The steps listed below describe how to remove the bottom
panel from the furnace. See Figure 16 (page 18).
1. Remove the door from the blower compartment.
2. Disconnect the blower motor wiring harness from the
control board.
3. Remove two screws securing the blower assembly to the
furnace.
4. Carefully pull the blower assembly out thru the front of the
furnace.
5. Remove all screws securing bottom panel to bottom of
furnace and front brace.
6. Lift up and slide bottom panel out through front of furnace.
7. Reinstall the blower assembly in reverse order.
Alternate Bottom Panel Removal
If the bottom panel cannot be removed using the previous
instructions, the steps below are an alternate method for
removing the bottom panel. See Figure 17 (page 18).
1. Remove the door from the blower compartment
2. Remove all screws securing the bottom panel to the front
brace.
3. Remove two screws securing the furnace cabinet to the
blower deck.
4. Remove all screws securing the furnace cabinet to the
bottom pane.
5. Remove the screw securing the bottom corner of the
furnace cabinet to the front brace.
6. Carefully spread the bottom corner of the furnace cabinet
outwards while sliding the bottom panel out through the
front of the furnace.
7. Reassemble the furnace in reverse order.

18
Bottom
Panel Front
Brace
Door
Wiring
Harness
Screws
Blower
Assembly
Screws
Figure 16. Bottom Panel Removal
Figure 17. Alternate Removal Method
Screws
Front
Brace
Bottom
Panel
Screws
Blower
Deck
Door
GAS SUPPLY & PIPING
WARNING:
FIRE OR EXPLOSION HAZARD
• Failure to follow safety warnings exactly could
result in serious injury or property damage.
• Installation and service must be performed
by a qualified installer, service agency or the
gas supplier.
• Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Leave the building immediately.
• Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the fire department.
• All gas piping must be installed in compliance with
local codes and utility regulations. In the absence of
local codes the gas line installation must comply with
the latest edition of the National Fuel Gas Code (ANSI
Z223.1) or (CAN/CGA B149.1) Installation Codes.
• Some local regulations require the installation of a
manual main shut-off valve and ground joint union
external to the furnace. The shut-off valve should be
readily accessible for service and/or emergency use.
Consult the local utility or gas supplier for additional
requirements regarding placement of the manual main
gas shut-off. See Figure 18 (page 19).
• Per ANSI 21.47, A 1/8-inch NPT plugged tapping,
accessible for test gauge connection, must be installed
immediately upstream of the gas supply connection to
the furnace external to the cabinet. If local codes allow
the use of a flexible gas appliance connector, always
use a new listed connector. Do not use a connector
that has previously serviced another gas appliance.
• Gas piping must never run in or through air ducts,
chimneys, gas vents, or elevator shafts.
• Compounds used on threaded joints of gas piping
must be resistant to the actions of liquefied petroleum
gases.
• The main gas valve and main power disconnect to the
furnace must be properly labeled by the installer in
case emergency shutdown is required.
• Flexible gas connectors are not recommended for
this type of furnace but may be used if allowed by
local jurisdiction. Only new flexible connectors may
be used. Do not reuse old flexible gas connectors.
• A drip leg should be installed in the vertical pipe run
to the unit. See Figure 18.

19
Figure 18. Typical Gas Connections
See
Note “B”
See
Note “B”
Right Side Entry
Left Side Entry
A
utomatic Gas Valvle
(w/ Manual Shut-Off)
Pipe
Nipple
Elbow
See
Note “A”
See
Note “A”
8
Shut-Off
Valve
Dripleg
Union
Manifold
Burner
Assembly
Plug
See Note “C”
Manifold
Burner
Assembly
Plug
A
utomatic Gas Valvle
(w/ Manual Shut-Off)
Shut-Off
Valve
Dripleg
Union
Pipe
Nipple
Elbow
NOTE A: Consult local codes for Shut- Off Valve location requirements.
NOTE B: Inducer assembly omitted for clarity of pipe installation.
NOTE C: Left side gas entry not available on ‘A’ width cabinets.
Leak Check
WARNING:
FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Never test for gas leaks with an open flame.
Use a commercially available soap solution
made specifically for the detection of leaks
to check all connections. A fire or explosion
may result causing property damage, personal
injury or loss of life.
After the gas piping to the furnace is complete, all connections
must be tested for gas leaks. This includes pipe connections
at the main gas valve, emergency shutoff valve and flexible
gas connectors (if applicable). The soap and water solution
can be applied on each joint or union using a small paintbrush.
If any bubbling is observed, the connection is not sealed
adequately and must be retightened. Repeat the tightening
and soap check process until bubbling ceases.
IMPORTANT NOTE
When pressure testing gas supply lines at pressures
greater than 1/2 psig (14 inch W.C.), the gas supply
piping system must be disconnected from the furnace
to prevent damage to the gas control valve. If the test
pressure is less than or equal to 1/2 psig (14 inch W.C.),
close the manual shut-off valve.
High Altitude Application (Natural Gas Only)
The installation of this furnace at altitudes above 2,000 feet
must meet the requirements of the National Fuel Gas Code
or local jurisdiction. In Canada, the requirements for high
altitude are different and governed by CGA B149.1. Please
consult your local code authority.
WARNING:
The reduction of input rating necessary for high
altitude installation may only be accomplished
with factory supplied orifices. Do not attempt to
drill out orifices in the field. Improperly drilled
orifices may cause fire, explosion, carbon
monoxide poisoning, personal injury or death.
The furnaces are shipped from the factory with orifices and
gas regulator settings for natural gas operation at sea level
altitudes. At 2,000 feet, the NFGC requires that this appliance
be derated 4% for each 1,000 feet of altitude. For example,
the input needs to be reduced 8% at 2,000 feet, 12% at 3,000
feet, etc. This deration is in reference to the input rate and
gas heating value at sea level.
To derate the furnace requires knowing the heating value of
the gas at the installation site. Heating values at particular
job sites vary for two reasons:
1. The chemical mixture of the gas varies from region to
region and is expressed as the “sea level heating value”.
2. The heating value varies by altitude. For this reason,
particularly in high altitude areas, the local gas utility usually
Table 6 (page 28) lists gas flow capacities for standard pipe
sizes as a function of length in typical applications based on
nominal pressure drop in the line.
NOTE: The ‘A’ width furnace can only be installed with right
side gas entry. ‘B’, ‘C’, & ‘D’ width furnaces may be installed
for either left or right side gas entry (only).
When connecting the gas supply, provide clearance between
the gas supply line and the entry hole in the furnace casing to
avoid unwanted noise and/or damage to the furnace. Typical
gas hookups are shown in Figure 18.

20
specifies the heating value at the residence’s gas meter
as the “local value”.
For added flexibility, two tables have been provided for
natural gas installations with high or low heating values at
sea level. Table 9 (page 30) & Table 10 (page 30) contain
the orifice sizes and manifold pressure to use at various
altitudes. Table 9 (HIGH) is for natural gas installations with
a heating value of more than 1,000 Btu per cubic foot and
Table 10 (LOW) is for less than 1,000 Btu per cubic foot. To
determine which table to use:
1. Consult your local utility for the local heating value at your
installation.
2. From Table 8 (page 29), find your local heating value as
supplied by the utility company. Follow down the column
and stop at your altitude level.
3. If your sea level heating value is HIGH, use Table 9 or if
it’s LOW, use Table 10. See example.
EXAMPLE
Elevation: ......................................................5,000 feet
Type of Gas:.............................................. Natural Gas
Local Heating Value of Gas:.................................. 750
From Table 8, find 750 and follow down the column, stop
at the 5,000 feet row. The heating value listed is LOW.
Table 10 will be used to determine orifice size and manifold
pressure.
After changing the regulator pressure or changing the orifices,
it is required that you measure the gas input rate. This may
be accomplished in the usual way, by clocking the gas
meter and using the local gas heating value. See Verifying
& Adjusting the Input Rate section (page 24).
IMPORTANT NOTE
Observe the action of the burners to make sure there is
no yellowing, lifting or flashback of the flame.
For US installations only: To avoid nuisance tripping
at altitudes from 7,500 to 10,000 feet, a pressure switch
conversion may be required. Consult the tables in the LP
and High altitude and LP gas conversion kit for installations
in the US.
Converting from Natural Gas to LP / Propane
WARNING:
The furnace was shipped from the factory
equipped to operate on natural gas. Conversion
to LP / Propane gas must be performed by
qualified service personnel using a factory
supplied conversion kit. Failure to use the proper
conversion kit can cause fire, explosion, property
damage, carbon monoxide poisoning, personal
injury, or death.
Conversion to LP / Propane is detailed in the installation
instructions provided with the conversion kit. Generally,
this will require the replacement of the burner orifices and
the spring assembly in the pressure regulator. Approved
conversion kits are listed below:
• Installations in the United States: For Propane (LP)
conversion or for LP gas installations in altitudes between
2,000 ft. and 10,000 ft. above sea level, use the LP &
High Altitude LP Gas Conversion Kit (P/N 905028) for
Installations in the United States. Please follow the
instructions provided with the kit.
• Installations in Canada: For Propane (LP) conversion or for
LP Gas installations in altitudes between zero and 4,500
ft. above sea level, use the LP & High Altitude LP Gas
Conversion Kit (P/N 905029) for Installations in Canada.
Please follow the instructions provided with the kit.
If the installation is in the U.S. above 2,000 ft., refer to Table 7
(page 29) to determine the correct orifice size and regulator
pressure. See Example below.
EXAMPLE
Elevation: ......................................................5,000 feet
Type of Gas:............................................ Propane Gas
Input BTUH of Furnace: ....................................80,000
From Table 7, find 5,000 and follow across the row; stop
at the 80,000 btuh column. At first stage, the manifold
pressure listed is 4.2, but at 2nd stage the pressure is 9.0.
The listed orifice size is 56.
When conversion is complete, verify the manifold pressure
and input rate are correct as listed in the Tables.