GAMA Gas-Fired Furnace Guide

INSTALLATION AND SERVICING
INSTRUCTIONS
AND
USER'S INFORMATION MANUAL
**INSTALLER — AFFIX THIS INSTRUCTION
PACKET ADJACENT TO THE FURNACE.
**HOMEOWNER — RETAIN THESE
INSTRUCTIONS FOR FUTURE REFERENCE.
INSTRUCTIONS D'ENTRETIEN ET
INSTALLATION
ET
MANUEL DE L'USAGER
**INSTALLATEUR -- PLACEZ LA POCHETTE
D'INSTRUCTIONS À COTÉ DU GÉNÉRATEUR
D'AIR CHAUD.
**PROPRIÉTAIRE -- CONSERVEZ CES
INSTRUCTIONS POUR Y RÉFÉRER PLUS TARD.
LITERATURE BOOKLET NO. 20557401
ISSUE 0442
20536912

Owner Record
Furnace Model #Serial #Installation Date
INSTALLED BY:
Dealer
Address
Telephone #License #
Contact Person
Other Equipment Installed:
Equipment Type
Model #Serial #Installation Date
Equipment Type
Model #Serial #Installation Date
Equipment Type
Model #Serial #Installation Date
WHEN FRENCH IS REQUIRED!
ATTENTION: MR. INSTALLER OR HOMEOWNER
TO OBTAIN INSTALLATION INSTRUCTIONS, USER'S INFORMATION MANUAL AND FURNACE
MARKINGS IN FRENCH CONSULT WITH YOUR DEALER OR LOCAL DISTRIBUTOR:
HAVE AVAILABLE THE MODEL NO. AND SERIAL NO. LOCATED ON THE UNIT RATING PLATE TO
INSURE THE CORRECT FRENCH INSTRUCTION PACKET.
POUR OBTENIR DE LA DOCUMENTATION EN FRANÇAIS!
ÀL'ATTENTION DE L'INSTALLATEUR OU DU PROPRIÉTAIRE
POUR OBTENIR LES INSTRUCTIONS D'INSTALLATION, LE MANUEL DE L'USAGER ET LES
MARQUAGES EN FRANÇAIS, CONSULTEZ VOTRE MARCHAND OU LE DISTRIBUTEUR DE VOTRE RÉGION:
AYEZ EN MAIN LE MODELE ET LE NUMÉRO DE SÉRIE INDIQUÉS SUR LA PLAQUE SIGNALÉTIQUE
DE L'APPAREIL POUR OBTENIR LA POCHETTE D'INSTRUCTIONS EN FRANÇAIS APPROPRIÉE.

USER'S INFORMATION MANUAL
Gas-Fired Furnace
READ ALL INSTRUCTIONS IN THIS MANUAL AND RETAIN THIS AND ALL ADDITIONAL INSTRUCTIONS FOR FUTURE REFERENCE.
Congratulations...
...you have one of the most modern gas furnaces made.
Your unit has been carefully selected to keep you warm
and comfortable during the winter months. It will deliver
superb performance with only minimal help from you.
To keep your operating costs low and to eliminate
unnecessary service calls, we have provided a few
guidelines. These guidelines will help you understand
how your gas furnace operates and how to maintain it so
you can get years of safe and dependable service.
GAMA Certified
The Gas Appliance Manufacturers Association (GAMA)
symbol verifies that Annual Fuel Utilization Efficiency
(AFUE) ratings for our gas furnaces have been derived
from U.S. Government standard tests.
CSA International Design Certified
The CSA International symbols on each nameplate is
your assurance that your furnace design meets nationally
recognized standards for safety and performance.
—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.
—Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
FIRE OR EXPLOSION HAZARD
Failuretofollowsafetywarningsexactly
could result in serious injury death or
property damage.
TABLE OF CONTENTS
SAFETY .......................... 2
OPERATING YOUR FURNACE ........... 2
Lighting Instructions ................. 2
Temperature Control ................. 3
Fan Operation ..................... 3
MAINTENANCE OF YOUR FURNACE ...... 4
Periodic Inspections ................. 4
Cleaning/Replacing the Filter ........... 5
Parts Replacement Guide ............. 6
20558901 Issue 0442 Page 1 of 6

For your safety -
Read before operating
Here are afew "Do's and Don'ts"
•Do become familiar with the User's Instruction
Manual and Installation Instructions.
•Do check to see that your home has adequate
insulation, weatherstripping, caulking, and storm
windows. Elimination of infiltration of outside air and
drafts can save up to 40% of your fuel bill.
•Do consider adding a humidifier to your heating
system. Higher indoor humidity slows evaporation
of perspiration, making the home seem warmer.
•Don't waste fuel by setting your thermostat too
high. Energy conservation experts recommend a
daytime thermostat setting of 68°F, with a lower
setting at night.
•Don't turn off the furnace when you expect to be
away for more than a day. Instead, lower the
thermostat setting a few degrees. You can then
restore normal comfort level quickly and save fuel
too.
•Don't block registers with furniture.
•Don't put a lamp, TV, or radio too near your
thermostat. This will cause it to give a false reading.
If you do not follow these instructions exactly, a fire
or explosion may result, causing property damage,
personal injury, or loss of life.
These furnaces are equipped with an ignition device
which automatically lights the burners. Do not try to
light the burners by hand.
Before operating, smell around the furnace area for gas.
Be sure to smell next to the floor because some gas is
heavier than air and will settle to the lowest point. Refer
to "What to do if you smell gas" on page 1 if the odor
of gas is present.
Use only your hand to adjust the gas control switch;
never use tools. If the switch will not move by hand,
don't try to repair it, call a qualified service technician.
Force or attempted repair may result in a fire or
explosion.
Do not use this furnace if any part has been under water.
A flood-damaged furnace is extremely dangerous.
Attempts to use the furnace can result in fire or explosion.
A qualified service agency should be contacted to inspect
the furnace and to replace all gas controls, control system
parts, electrical parts that have been wet or the furnace
if deemed necessary.
The furnace area must be kept clear and free of
combustible materials, gasoline, and other
flammable vapors and liquids. Failure to do so
could cause actions that may result in property
damage, personal injury, or loss of life.
Operating Your Furnace
Lighting Instructions
1. STOP! Read the previous safety information.
2. Set the thermostat to the lowest setting.
3. Turn off all electric power to the furnace.
4. Remove the burner compartment access panel.
5. This appliance is equipped with an automatic ignition.
device. Do not try to light the burners by hand.
6. Move the gas control knob to "OFF" (see Figure 1).
Figure 1
7. Wait 5 minutes to clear out any gas, then smell for
gas (including at the bottom of the unit near the
ground). If you smell gas, stop and follow the
directions in "What to do if you smell gas" on page
1. If you don't smell gas, continue to next step.
8. Move the gas control knob to "ON".
9. Replace the burner compartment access panel.
10. Turn on all electric power to the furnace.
20558901 Issue 0442 Page 2 of 6

11. Set the thermostat to the desired setting.
12. If the furnace will not operate, follow the instructions
in "To Turn Off Gas to Furnace" and call your
service technician or gas supplier.
To Turn Off Gas to Furnace
1. Set the thermostat to the lowest setting.
2. Turn off all electric power to the furnace if service is
to be performed.
3. Remove the burner compartment access panel.
4. Move the gas control switch to "OFF" (see Figure 1).
Do not force.
5. Replace the burner compartment access panel.
Temperature Control
There are many types and styles of thermostats. Yours
may look different from the one pictured in Figure 2,
depending on the type of thermostat and whether cooling
was installed with the system. However, almost all
thermostats perform the same basic functions described
in the following section.
Figure 2
Thermostat Operation
There are four (4) buttons on the thermostat (see Figure
2). One button controls the heating and cooling (if
applicable) functions. Another button is for "FAN"
operation, either continuous or automatic. The remaining
two buttons set the temperature range for the heating
temperature and the cooling temperature desired.
To put the system into operation, push the button to
either "HEAT" or "COOL" position. After you have chosen
the type of operation you desire, set the thermostat to
the temperature you would like the system to maintain.
Fan Operation
You may wish to increase your comfort by setting your
system for continuous air circulation of the indoor air.
The fan switch on the thermostat permits you to do this.
With the switch in the "ON" position the fan will operate
continuously. "AUTO" position gives fan operation only
when the unit is in either heating or cooling.
What to do if your unit is not heating properly
If your furnace is operating but fails to provide complete
comfort, check the following before calling for service:
1. Be sure the thermostat setting is correct.
2. Check to see if the filter is clean.
3. Be sure air can circulate freely throughout your home.
Do not block supply registers or return grilles with
furniture or rugs.
And if you also have cooling...
4. Keep surface of the outdoor coil free from dirt, lint,
paper, or leaves.
5. Check and clean indoor coil, if necessary. (This
check should be made at the start of each cooling
season by your service technician).
What to do if your unit fails to operate
1. Be sure the main switch that supplies power to the
furnace is in the "ON" position.
2. Replace any burned-out fuses or reset circuit
breakers.
3. Be sure the thermostat is properly set.
4. If the furnace still does not start, call your service
technician.
Should the gas supply fail to shut off or if
overheating occurs, shut off the gas valve to the
furnace before shutting off the electrical supply.
20558901 Issue 0442 Page 3 of 6

Maintenance Of Your Furnace
Always shut off all power to the unit before
attempting any of the following maintenance
procedures. Failure to do so may result in personal
injury.
There are routine maintenance steps you should take to
keep your furnace operating efficiently. This maintenance
will assure longer life, lower operating costs, and fewer
service calls. In addition to the maintenance procedures
listed in this manual, there are also other service and
maintenance procedures that require the skills of a
service person who has specialized tools and training.
(See "Servicing the Furnace" section of the Installation
and Servicing part of this booklet.) Personal injury can
result if you are not qualified to do this work. Please
call your dealer when service is needed.
Cleaning
The cabinet of the furnace can be cleaned with soap and
water. Grease spots can be removed with a household
cleaning agent. The cabinet can be kept attractive by
polishing with automotive wax at least twice a year.
Installations Around Insulation
Insulating materials may be combustible. Therefore, a
furnace installed in an attic or other insulated space must
be kept free and clear of insulating materials. Make sure
to examine the furnace area when the furnace is installed
or additional insulation has been added.
Periodic Inspections
Your gas furnace is designed to give many years of
efficient, satisfactory service. However, the varied air
pollutants commonly found in most areas can affect
longevity and safety. Chemicals contained in everyday
household items such as laundry detergents, cleaning
sprays, hair sprays, deodorizers, and other products
which produce airborne residuals may have an adverse
affect upon the metals used to construct your appliance.
It is important that you conduct periodic physical
inspections of your appliance, paying special attention to
the gas burner and the flue outlet from the furnace.
These components are located at the front of the unit. A
flashlight will be useful for these inspections. Make one
inspection prior to the beginning of the heating season
and another during the middle.
Should you observe unusual amounts of any of the
following conditions, it is important that you call your
authorized dealer at once to obtain a qualified service
inspection:
•Rust, flakes, or other deposits
•Coatings
•Corrosion
Even if no unusual rust or other conditions are observed,
it is recommended that the furnace be inspected and
serviced at least once per year by a qualified service
technician. Regular inspection and planned
maintenance will assure many years of economical
performance from your gas furnace.
Combustion Air
Adequate combustion and ventilation air must reach
your gas furnace to provide for proper and safe
operation. Do not block or obstruct air openings on
the furnace, air openings communicating with the
area in which the furnace is installed and the
spacing around the furnace. Any obstruction of this
airflow can cause an unsafe condition which may
result in death or permanent injury.
Furnaces located in a closet, alcove, or utility room must
have provision for adequate air supply by means of upper
and lower grilles in the door, or by the introduction of
outside air, or both. National Fuel Gas Code, ANSI
Z223.1 (latest edition), CAN/CGA B149.1 &.2 Installation
Codes (latest edition), and local requirements are
generally alike. However, local codes take precedence.
Venting and Furnace Support
Venting of this furnace must comply with our published
instructions. Be sure the installer has followed these
requirements. If not, you should request the installer to
comply as soon as possible.
For your safety, please note the following:
1. This is a category IV furnace and is dual certified as
a direct vent furnace (two pipe system) using outside
air for combustion or as a non-direct vent furnace
(one pipe system) using air from inside the structure
for combustion. The vent - air intake system must be
with schedule 40 PVC, CPVC or ABS pipe including
all elbows and vent terminals. All pipe and fittings
must conform to the American Society for Testing and
Material (ASTM), and American National Standards
Institute (ANSI) Standards.
Common venting with other condensing appliances
or non-condensing appliances is not allowed.
20558901 Issue 0442 Page 4 of 6

In all direct vent (two pipe) instances, the vent
outlet shall be installed so as to be in the same
atmospheric pressure zone as the combustion air
intake.
2. This furnace is not designed for use with a vent
damper. Use of such a device will not improve the
efficiency of this furnace and can cause an unsafe
condition which may result in death or permanent
injury.
The vent-air intake system from your furnace may rise
vertically and terminate above the roof or horizontally
through the outside wall.
Make sure all air intake and flue product carrying areas
external to the furnace (i.e., vent terminal) are clear and
free of obstructions. The vent-air intake system and
condensate drain system is in place, is physically sound
without holes or excessive deterioration, and is installed
in accordances with the installation instructions.
Check to see that the furnace cabinet is sound and firmly
supported, without sagging. There should be no cracks
or gaps between the furnace and the base or floor, which
would permit entry of unfiltered air.
It is important that the outside area where the vent
terminates is kept clear of any obstructions which might
block or impede the venting of the furnace. Should
venting become blocked at anytime, your furnace is
equipped with a special safety control to prevent
operation of the furnace until the condition has been
corrected. Contact your dealer if you desire more
information about this safety feature.
Should any unusual conditions be observed during your
inspections, call an authorized service dealer immediately.
For proper venting terminations, see the Installation
Instructions furnished with the furnace.
Return Air
Ascertain that all return air duct connections are tight and
sealed to the furnace cabinet and that all return air grilles
or registers are located outside the space containing the
furnace.
Cleaning/Replacing the Filter
It is very important to clean or replace the air filter
regularly. Dirty filters are the most common cause of
inadequate heating or cooling performance and can
sharply increase the operational costs of your unit. In
some cases, they can double the cost. The air filter
should be inspected at least every 6 weeks and
cleaned or replaced as required.
Your furnace may use either a disposable filter,
permanent filter, electronic or high efficiency media air
cleaner. Consult filter/cleaner manufacturer for
maintenance service and static pressure drop for air
moving requirements.
Permanent filters may be replaced with disposable filters.
Refer to Table 1 when selecting the proper size and
quantity of disposable filter.
If your air distribution system has a central return air filter-
grille, you do not need a filter in your furnace.
Table 1 EXTERNAL FILTER RACK SIZE
* SIDE RETURN BOTTOM/END RETURN
15 ½ X 25 12 X 25
15 ½ X 25 15 ½ X 25
15 ½ X 25 19 X 25
*NOT FOR USE WITH COUNTER (DOWN) FLOW MODELS
Safety Interlock Switch
The blower compartment door on your high efficiency gas
furnace is equipped with a safety interlock switch that will
automatically shut off your complete system (including
blower) once the door is removed. This is for your
personal safety. Be sure to check your furnace for proper
operation once the door or panel has been replaced.
If the system does not operate once the panel has been
replaced, try removing and replacing it once again. If the
furnace still does not operate, call your dealer for service.
Rollout Switch
This unit is equipped with a manual reset high
temperature sensor or rollout switch. In the unlikely event
of a sustained main burner flame rollout, the rollout switch
will shut off the flow of gas by closing the main gas valve.
The switch is located inside the gas burner area. Flame
rollout can be caused by blockage of the power vent
system, a blocked heat exchanger, or improper gas
pressure or adjustment. If this event occurs, the unit will
not operate properly. The gas supply to the unit should
be shut off and no attempt should be made to place it
in operation.The system should be inspected by a
qualified service technician.
Lubrication
Lubrication of the bearings in the circulating air blower
motor and the combustion blower motor is not
recommended.
Burner Flame
While the furnace is in operation, observe the main
burner flames. Compare these observations to Figure 3
to determine if proper flame adjustment is present. If
your observations indicate improper flame adjustment, call
your authorized service dealer for service.
20558901 Issue 0442 Page 5 of 6

Figure 3
Do not attempt to adjust flame! Your service
representative will perform this adjustment correctly.
Condensate Collection and Disposal System
If the furnace has a condensate drain, it is
incorporated within the furnace and is selfpriming.
The condensate system must not be exposed to
temperatures under 32°F. Use of heat tape is
permissible provided the rate temperature of tape
does not exceed 155°F.
Make sure the condensate drain line does not become
blocked or plugged. Visual inspection of condensate flow
can easily be made while the furnace is operating. Use
a flashlight to illuminate discharge end of the condensate
drain that is placed in the sewer opening. The furnace
will not operate properly if condensate drain line becomes
blocked or plugged. If this event occurs, have the
furnace inspected by a qualified service technician.
Warranty Procedure
When warranty parts are required:
1. Be prepared to furnish the following information:
a. Purchaser's name
b. Complete model number, serial number, and
date of installation.
c. An accurate description of the problem or
defective parts.
2. Contact your dealer or distributor.
Keep this User's Information Manual (including
Warranty) and proof of purchase for your records.
Your warranty is determined from your date of
installation. If proof of your date of installation is not
supplied, the warranty will be based on the
manufacture date code.
Failure to follow the correct warranty procedure could
result in disallowance of warranty claim.
PARTS REPLACEMENT INFORMATION GUIDE
CASING GROUP GAS CONTROL GROUP BLOWER GROUP
Top Panel Manifold Blower Housing
Front Door Burner Blower Motor
Blower Door Shield Top & Bottom Blower Wheel
Burner Access Door Orifice Capacitor
Control Access Door Ignitor Blower Support Leg
Gas Valve
Sensor
ELECTRICAL GROUP HEAT EXCHANGER GROUP INDUCER GROUP
Limit Switch Primary Heat Exchanger Pressure Switch (Low Fire)
Control Board Condensing Heat Exchanger Pressure Switch (High Fire)
Transformer Burner Box Panel Inducer Blower & Motor
Rollout Switch Burner Inlet Plate Inducer Blower Switch
Door Interlock Switch Flue Box Pressure Switch Tubering
Auxiliary Limit Switch (when used)
CONDENSATE DISPOSAL GROUP
Condensate Trap
Condensate Hoses
TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or classified section of your local telephone
directory under the "Heating Equipment" or "Air Conditioning Contractors & Systems" headings for dealer listing or see the
first page of the installation instruction section of this manual for the name and address to contact.
Have available the Model No. and Serial No. located on the unit rating plate to insure correct replacement part.
WARNING: Improper installation, adjustment, alteration, service or maintenance can cause personal injury or property
damage. Consult a qualified installer, service agency, or your local gas supplier for information or assistance.
20558901 Issue 0442 Page 6 of 6

AFFIX LABEL HERE
INSTALLATION INSTRUCTIONS
UPFLOW OR LEFT HORIZONTAL
TWO STAGE HEAT VARIABLE SPEED
GAS-FIRED CONDENSING
WARM AIR FURNACE
Issue 0442
TABLE OF CONTENTS
Safety ........................................... 2
Furnace Specifications ............................... 3
Introduction ....................................... 6
Location/Placement .................................. 6
Air for Combustion & Ventilation ........................ 8
Ducting .......................................... 11
Venting .......................................... 12
Electrical Connections ................................ 19
Gas Connections ................................... 19
Control Board & Variable Speed Motor Features ............. 21
Unit Sequence of Operation ............................ 22
Start-Up Operation & Checkout ......................... 23
Sequence of Operation ............................... 28
Servicing The Furnace ............................... 29
Control System Diagnostics ............................ 31
Wiring Diagram ..................................... 32
RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
Installation and service must be performed
by a qualified installer, service agency or
the gas supplier. Installation by an
unqualified person may lead to equipment
damage and/or a hazardous condition
which may cause bodily injury and harm
and, as such, at the sole discretion of the
manufacturer, the entire warranty may be
voided and be of no further force and
effect.
WHAT TO DO IF YOU SMELL GAS:
•Do not try to light any appliance.
•Extinguish any open flame.
•Do not touch any electrical switch; do
not use any phone in your building.
•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.
20558801 Issue 0442 Page 1 of 32

SAFETY
The following is a list of safety precautions and their locations in this manual.
These safety rules and precautions must be followed when installing this furnace.
1. Use only with type of gas approved for this furnace. Refer to the furnace rating
plate.
2. Install this furnace only in a location and position as specified in The
Location/Placement Section on page 6of these instructions.
3. Provide adequate combustion and ventilation air to the furnace space as
specified in Air for Combustion and Ventilation section on page 8 of these
instructions.
4. Combustion products must be discharged outdoors. This furnace requires a
special vent system with adequate clearances around the vent-air intake terminal
(s), as specified in Venting on page 12 of these instructions.
5. As a TYPE FSP CATEGORY IV furnace the combustion air connections, the flue
gas connection, the vent-air intake terminal and condensate trap and drain
system must be as specified in the Venting section starting on page 12 of these
instructions. Venting and drain materials must be as specified and are to be
supplied by the installer. On direct vent systems the vent outlet shall be installed
so as to be in the same atmospheric pressure zone as the combustion air intake.
6. 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, as
specified in The Gas Connection section on page 19 of these instructions.
7. Always install furnace to operate within the furnace's intended temperature-rise
range with a duct system which has an external static pressure within the
allowable range, as specified in Furnace Specifications on page 3 of these
instructions. See furnace rating plate.
8. When a furnace is installed so that 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 outside
the space containing the furnace. See page 11 for Ducting.
9. A gas-fired furnace for installation in a residential garage must be installed as
specified in The Location / Placement section on page 6 of these instructions.
10. The furnace is not to be used for temporary heating of buildings or structures
under construction. As noted on page 6 under Introduction.
20558801 Issue 0442 Page 2 of 32

FURNACE SPECIFICATIONS
MODEL
UNIT DIMENSIONS DUCT SUPPLY
OPENING
DUCT
RETURN
OPENING
AIR INLET
& VENT
CONNECTION
DIA.*
MAX. OVER
CURRENT
PROTECTION
MAX.
UNIT
AMPS
ELECTRICAL
SUPPLY MIN.
WIRE SIZE(AWG)
TEMPERATURE
RISE
RANGE
NET
WEIGHT
LBS
LENGTH WIDTH HEIGHT
A B C D EFGH
EV050U3 29 1/2 13 1/2 47 3/8 11 1/2 18 15/16 12 21 5/8 215 9.9 14 45-55 131
EV075U3 29 1/2 13 1/2 47 3/8 11 1/2 18 15/16 12 21 5/8 215 9.9 14 50-60 140
EV100U4 29 1/2 17 47 3/8 15 18 15/16 15 1/2 21 5/8 215 11.8 14 50-60 167
EV125U5 29 1/2 20 1/2 47 3/8 18 1/2 18 15/16 19 21 5/8 220 15 12 50-60 193
* SEE TABLES 3 AND 4 ON PAGES 15 AND 16 FOR ALLOWABLE MAX VENT AND AIR INLET LENGTHS AND DIAMETERS.
20558801 Issue 0442 Page 3 of 32

BLOWER MOTOR SPECIFICATIONS AND AIRFLOW ADJUSTING DATA
Adjusting Airflow
MODEL MOTOR
HP BLOWER WHEEL
HEAT SETTING COOL SETTINGS
ADJUST HEAT COOL CFM @ .50 STATIC
HEATING CFM ADJUSTMENT SETTING "A" SETTING "B" SETTING "C" SETTING "D"
EV050U3 1/2 10 X 6
NORM ANORM 1200 1000 800 600
LOW FIRE 600 ( + ) 1380 1150 920 690
HIGH FIRE 775 ( - ) 1020 850 680 510
EV075U3 1/2 10 X 6
NORM ANORM 1200 1000 800 600
LOW FIRE 1000 ( + ) 1380 1150 920 690
HIGH FIRE 1230 ( - ) 1020 850 680 510
EV100U4 3/4 12 X 9
NORM ANORM 1600 1400 1200 1000
LOW FIRE 1240 ( + ) 1800 1610 1380 1150
HIGH FIRE 1550 ( - ) 1360 1190 1020 850
EV125U5 112 X 12
NORM ANORM 2000 1800 1600 1400
LOW FIRE 1250 ( + ) 2200 2070 1840 1610
HIGH FIRE 1940 ( - ) 1700 1530 1360 1190
When operating the furnace in the heating mode, the static pressure and the temperature rise (supply air temperature
minus return air temperature) must be within those limits specified on the rating label. Failure to follow this warning
could lead to severe furnace damage.
Turn OFF all gas and electrical power to furnace before performing any maintenance or service on unit. (Unless
specific test requires gas and electrical supplies.) Failure to take this precaution may result in personal injury due
to electrical shock or uncontrolled gas leakage.
20558801 Issue 0442 Page 4 of 32

FURNACE WIRING SPECIFICATIONS
20558801 Issue 0442 Page 5 of 32

The furnace cabinet must have an uninterrupted or unbroken electrical ground to minimize personal injury if an
electrical fault should occur. The unit must also be electrically grounded in accordance with local codes, or in the
absence of local codes, with the latest edition of the (U.S.) National Electrical Code ANSI/NFPA No. 70 or CSA
Standard C22.1; Part 1 Canadian Electrical Code, if an external electrical source is utilized. DO NOT use gas piping
as an electrical ground.
INTRODUCTION
This furnace is design certified by CSA International as a category IV furnace and is dual certified as direct vent furnace
(two pipe system) using outside air for combustion or as a non-direct vent furnace (one pipe system) using air from inside
the structure for combustion.
It is shipped as a packaged unit, complete with burners and controls, and requires a line voltage (120V) connection to
the junction box, a thermostat hook-up as per the wiring diagram, a gas line connection, a condensate drain connection,
ducting and flue piping. This furnace can be installed in either upflow or horizontal (left) airflow positions at no time
should this unit be operated on its back. The design of this furnace is NOT CSA Certified for installation in
recreation vehicles, in manufactured (mobil) homes, outdoors or for temporary construction heating.
This furnace has been designed to interface with split system cooling equipment (approved by a nationally recognized
testing laboratory) so as to provide "year round air conditioning". The blower has been sized for both heating and cooling
and is equipped with a variable speed circulation air blower motor to deliver a constant air flow.
The furnace installation must conform with local building codes or in the absence of local codes, with the latest edition
of the (U.S.) National Fuel Gas Code ANSI Z223.1 (NFPA-54) or Canadian Natural Gas and Propane Installation Codes
CSA B149.1.
For complete information on installation standards consult the (U.S.) National Fuel Gas Code, obtainable from the
National Fire Protection Association, Inc., Batterymarch Park, Quincy, MA 02269 or the American Gas Association, 1515
Wilson Boulevard Arlington, VA 22209 or the Canadian installation codes obtainable from Canadian Standards Association,
178 Rexdale Boulevard, Etobicoke, Ontario, Canada M9W 1R3.
This furnace is designed for minimum continuous return-air temperature of 60°F dB or intermittent operation down to
55°F dB such as when used with a night setback thermostat. Return-air must not exceed a maximum continuous
temperature of 85°F dB.
These instructions are written for individual residential installation only. For multi-unit installation or
commercial applications, please contact manufacturer for recommendations.
LOCATION / PLACEMENT
Site Selection:This furnace may be located in an attic, closet, basement, crawl space, alcove or suspended from the
ceiling of a utility room or basement. Select a location that will meet all requirements for safety,
clearances, ventilation and combustion air, ductwork design, gas piping, electrical wiring and venting.
Clearances: The following minimum clearances, or greater, must be provided between the furnace and adjacent
construction.
TABLE 1MINIMUM INSTALLATION CLEARANCES
"UPFLOW" POSITION "HORIZONTAL (LEFT)" POSITION
Suitable for alcove or closet installation† on combustible
flooring at minimum clearance from adjacent construction
not less than the following:
Suitable for attic, alcove or closet installation† on
combustible flooring at minimum clearance from adjacent
construction not less than the following:
* Line contact only permissible between lines formed by
intersection of the top and two sides of the furnace jacket
and building joist, studs, or framing.
Top Sides Back Front Vent
2" 1" 1" 3" 0"
† For closet installation see Air for Combustion and Ventilation.
20558801 Issue 0442 Page 6 of 32

Failure to comply with all of the clearances will
create a fire hazard.
INSTALLATION POSITIONS
The furnace should not be connected to an
operational chimney. The furnace should also be located
as near to the center of the air distribution system as
possible, and should be installed level.
This furnace may be installed on non-combustible or
on wood flooring, however, it must not be installed
directly on carpeting, tile or any other combustible
material.
In a horizontal position, line contact with combustibles
is only permissible between lines formed by the
intersection of the furnace top, the front and back sides,
and building joists, studs or framing (See Figure 1).
Figure 1HORIZONTAL LINE CONTACT
Furnace must not lean back. It must be level or
tilt up to 2°to the front. (See Figure 1.)
A clearance of at least 30" should be provided at the
front of the unit for servicing. For attic installations, the
passageway and servicing area adjacent to the furnace
should be floored.
If furnace is tilted back condensate will collect in the
secondary heat exchanger which will result in
improper combustion, fire hazard, or other unsafe
conditions which could result in property damage,
personal injury or death.
If the furnace is to be installed in a crawl space,
consult local codes. (Use of a concrete pad 1" to 2" thick
is recommended.)
If the furnace is to be suspended from the ceiling, it
will be necessary to use steel pipe straps around each
end of the furnace. These straps should be attached to
the furnace with sheet metal screws and to the rafters
with bolts. The furnace may also be suspended by using
an angle iron frame bolted to the rafters. (See Table on
page 3 for size and weight of furnace.) Care must be
taken to allow for service access.
If a furnace is to be installed in a residential garage,
it must be installed so the burners and the ignition source
are located not less than 18" above the floor and the
furnace must be located or protected to avoid physical
damage by vehicles.
If this furnace is installed in a garage and/or any
unconditioned space, where local plumbing code
would require potable water supply piping to be
protected; a thermostatically controlled heat tape
must be installed along the entire length of the
condensate drain in the unconditioned space. Any
blockage of the condensate drain will result in
improper combustion, fire hazard, or other unsafe
conditions which could result in property damage,
personal injury or death.
Do not place combustible material on the furnace
jacket. Failure to comply with this warning will
create a fire hazard.
This furnace is not watertight and is not designed
for outdoor installation. This furnace shall be
installed in such a manner as to protect the
electrical components from water. Outdoor
installation would lead to a hazardous electrical
condition and to premature furnace failure.
20558801 Issue 0442 Page 7 of 32

AIR FOR COMBUSTION AND VENTILATION
Contaminated Combustion Air:
If the furnace is to be installed in a structure defined
as having contaminated combustion air, the furnace must
use the direct vent (two pipe) configuration using non-
contaminated outside air for combustion. Allowing
exposure to substances containing chlorine or fluoride
could harm the furnace and void the warranty.
Substances to avoid include, but are not limited to:
•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 (such as perchloroethylene)
•Printing inks, paint removers, varnishes, etc.
•Hydrochloric acid
•Cements and glues
•Antistatic fabric softeners for clothes dryers
•Masonry acid washing materials
•Unrefined gases
Contaminated combustion air may cause premature
failure of the heat exchanger that may lead to a
hazardous condition and/or bodily harm, or loss of
life.
Adequate Ventilation and Combustion Air:
This section is provided to give guidelines for the
introduction of air for ventilation and combustion air. The
total quantity of air provided to the installation area must
equal the requirements of all gas appliances in the area.
Adequate facilities for providing air for combustion
and ventilation must be provided in accordance with the
latest edition of the National Fuel Gas Code ANSI
Z223.1/NFPA54 orCSA B149.1 Natural Gas and Propane
Installation Codes, or applicable provisions of the local
building codes.
The furnace shall be installed in a location in which
the facilities for ventilation permits satisfactory combustion
of gas, proper venting and maintenance of ambient
temperature at safe limits under normal conditions of use.
The furnace shall be located so as not to interfere with
proper circulation of air.
In addition to air needed for combustion, ventilation in
the form of process air must be provided as required for:
cooling of equipment or material, controlling dew point,
heating, drying, oxidation or dilution, safety exhaust and
odor control. Air must be supplied for ventilation,
including all air required for comfort and proper working
conditions for personnel. Direct venting (two pipe)
allows for the combustion air to be supplied directly
to the furnace from the outdoors. Ventilation needs
only to be considered when furnace is installed as
direct vent (two pipe). Non-direct venting (one pipe)
requires both combustion and ventilation air
requirements from the furnace location.
For purposes of this instruction the following
definitions apply:
Confined Space: A space whose volume is less
than 50 cubic feet per 1000
Btu/hr of the aggregate input
rating of all appliances installed
in that space.
Unconfined Space: A space whose volume is not
less than 50 cubic feet per 1000
Btu/hr of the aggregate input
rating of all appliances installed
in that space. Rooms
communicating directly with the
space in which the appliances
are installed, through openings
not furnished with doors, are
considered a part of the
unconfined space.
If the installation area meets the definition of
"Unconfined Space" and does not have additional air
requirements as described, the furnace may be installed
without making special provisions for combustion and
ventilation air.
Whenever this furnace is installed in an area along
with one or more gas appliances, the total Btu/hr
input of all appliances (using maximum input of
each appliance) must be included when determining
the free area requirements for combustion and
ventilation air openings.
Do not block the combustion or ventilation air
openings in the furnace. Any blockage will result in
improper combustion and may result in a fire
hazard or unsafe condition.
20558801 Issue 0442 Page 8 of 32

If ventilation and/or combustion air must be supplied to the "Confined Space" from inside the building structure, two
permanent openings to an additional room of sufficient volume as to combine the volumes of the spaces to meet the
criteria for an "Unconfined Space" must be created. Each opening must have a free area of not less than one square
inch per 1000 Btu per hour of total input of all appliances within the "Confined Space" (but not less than 100 square
inches). These openings must be located 12 inches from the top and bottom of the furnace area respectively and must
be at least 3 inches long on the smaller side of the opening (See Figure 2). Neither opening can be blocked at any time.
Figure 2CONFINED SPACE / INDOOR AIR
TOTAL INPUT
(Btuh) MIN. FREE AREA (Sq. In.) ROUND DUCT (Dia. In.)
40,000
60,000
80,000
100,000
120,000
140,000
160,000
100
100
100
100
120
140
160
12
12
12
12
13
14
15
EXAMPLE:
50,000 Btuh Furnace & 10,000 Btuh Water
Heater = 60,000 Btuh Total Input = 12"
Dia. Round Duct.
If ventilation and/or combustion air must be supplied to the "Confined Space" from outside the building structure,
two permanent openings to the outdoors must be created. Each opening must have a free area of not less than one
square inch per 4000 Btu per hour of total input of all appliances within the "Confined Space". These openings must
be located 12 inches from the top and bottom of the furnace area respectively (See Figures 3, 4, and 5). Neither
opening can be blocked at any time.
Figure 3CONFINED SPACE / OUTDOOR AIR
TOTAL INPUT
(Btuh) MIN. FREE AREA (Sq. In.) ROUND DUCT (Dia. In.)
40,000
60,000
80,000
100,000
120,000
140,000
160,000
10
15
20
25
30
35
40
4
5
5
6
6
7
8
EXAMPLE:
50,000 Btuh Furnace & 10,000 Btuh Water
Heater = 60,000 Btuh Total Input = 5" Dia.
Round Duct.
20558801 Issue 0442 Page 9 of 32

Figure 4
CONFINED SPACE / OUTDOOR AIR
FROM ATTIC
Figure 5
CONFINED SPACE / OUTDOOR AIR
FROM ATTIC & CRAWL SPACE
For an attic installation it is important to keep
insulation 12" or more away from any furnace
openings. Some types of insulating materials may
be combustible.
When horizontal ducts are used to supply air from the
outdoors, they must be of the same cross sectional area
as the free area of the openings to which they connect.
The minimum dimension of rectangular air ducts must not
be less than 3 inches. Each opening must have a free
area of not less than one square inch per 2,000 Btu per
hour of total input of all appliances within the "Confined
Space". These openings must be located 12 in. from the
top and bottom of the furnace area. Neither opening can
be blocked at any time (See Figure 6).
Figure 6CONFINED SPACE / OUTDOOR
AIR THROUGH HORIZONTAL DUCTS
Furnaces installed with combustion air drawn from
a heated space which includes exhaust fans,
fireplaces, or other devices that may produce a
negative pressure should be considered confined
space installations.
20558801 Issue 0442 Page 10 of 32

DUCTING
The proper sizing of warm air ducts is necessary to insure satisfactory heating operation. Ductwork should be in
accordance with the latest editions of (U.S.) NFPA-90A (Air Conditioning Systems) and NFPA-90B (Warm Air Heating
and Air Conditioning Systems) or Canadian equivalent.
Ductwork Recommendation:
The supply duct work should be attached to the
flanged opening provided at the discharge end of the
furnace. See page 3 "Furnace Specifications" for the
dimensions of this opening.
A left, right, or bottom return air opening must be
used as determined by the layout of the installation. An
externally mounted air filter is required.
This furnace has a two piece bottom panel. For
bottom or end duct return, remove the back portion of the
bottom panel by removing the four (4) screws - two (2) on
each side toward the back of the furnace (See Figure 7).
Tilt furnace toward the front, the back portion of the panel
will drop down. Then the back portion can be removed
by pulling toward the back of the furnace.
Figure 7BOTTOM PANEL REMOVAL
Knockouts are provided on both sides of the furnace
to facilitate the cutout required to the return air ductwork.
Furnace cutouts must be the full size specified by the
corner markers. Undersized cutouts will adversely
affect the airflow capability of the furnace and could
cause overheating of the heat exchanger.
The following recommendations should be followed
when installing the ductwork:
1. Install locking-type dampers in all branches of the
individual ducts to balance out the system. Dampers
should be adjusted to impose the proper static at the
outlet of the furnace.
2. Noncombustible flexible duct connectors are
recommended to connect both the supply and return
ducts to the furnace.
3. In cases where the return air grille is located close to
the blower inlet, there should be at least one 90° air
turn between blower and return grille. Further
reduction in sound can be accomplished by installing
acoustical air turning vanes and/or lining the inside of
the duct with acoustical material.
4. It is recommended that the supply duct be provided
with a removable access panel. This opening shall
be accessible when the furnace is installed and shall
be of such a size that the heat exchanger can be
viewed for possible openings using light assistance or
a probe can be inserted by sampling the air stream.
The access panel shall be designed so as to prevent
leaks when locked in position. If an air conditioning
coil is installed, the access panel to the coil can be
used for this purpose.
When supply ducts carry air circulated by the
furnace to areas outside the spaces containing the
furnace, the return air shall also be handled by a
duct sealed to the furnace casing and terminating
outside the space containing the furnace. Incorrect
ductwork termination and sealing will create a
hazardous condition that could lead to bodily harm.
Air openings, intake and outlet pipes, return air
grilles and warm air registers must not be
obstructed.
Filters:
Air filters must be used in every installation. For side
return installations, air filters must be installed external to
the furnace casing. An external filter rack kit with filter
(parts No. 20069901 or Cat. No. 68L75 for 12 / 15½" x
25" sizes and 20069902 or Cat. No. 68L76 for 15½ / 19"
x 25" sizes) is available as an optional accessory.
For bottom (end) return installations, the above
optional external rack may be used, if the unit was not
provided with a internal filter. Minimum filter size and
suggested filter materials are shown in Table 2. (If
different type filter is used, it must be an equivalent high
airflow capacity.)
Table 2 EXTERNAL FILTER RACK SIZE
MODEL SIDE
RETURN BOTTOM/END RETURN
050-3
075-3 15 ½ X 25 12 X 25
100-4 15 ½ X 25 15 ½ X 25
125-5 15 ½ X 25 19 X 25
20558801 Issue 0442 Page 11 of 32

When installing the furnace with cooling equipment for
year round operation, the following recommendations
must be followed for series or parallel air flow:
1. In series flow applications, the coil is mounted after
the furnace in an enclosure in the supply air stream.
The furnace blower is used for both heating and
cooling airflow.
2. In parallel flow installation, dampers must be provided
to direct air over the furnace heat exchanger when
heat is desired and over the cooling when cooling is
desired. At no time may the evaporator coil be
located on the return air side of the heat exchanger.
IMPORTANT: The dampers should be adequate to
prevent cooled air from entering the
furnace, and if manually operated, must
be equipped with means to prevent
operation of either the cooling unit or
furnace unless the damper is in the full
cool or full heat position.
The coil MUST be installed on the air discharge
side of the furnace. Under no circumstances
should the air flow be such that cooled, conditioned
air can pass over the furnace heat exchanger. This
will cause condensation in the heat exchanger and
possible failure of the heat exchanger that could
lead to a fire hazard and/or hazardous conditions
that may lead to bodily harm. Heat exchanger
failure due to improper installation will not be
covered by warranty.
VENTING
Venting for this category IV furnace must be with
schedule 40 PVC, CPVC or ABS pipe including all elbows
and vent terminals. All pipe and fittings must conform to
the American Society for Testing and Material (ASTM),
and American National Standards Institute (ANSI)
Standards. PVC primer and solvent cement used to
secure all PVC joints must conform to ASTM D2564.
Common venting with other condensing appliances
or non-condensing appliances is not allowed.
In all direct vent (two pipe) instances, the vent
outlet shall be installed so as to be in the same
atmospheric pressure zone as the combustion air
intake.
All combustion air and exhaust piping must be
installed in accordance with local codes and these
instructions. For additional venting information refer to
ANSI/NFPA 211 Chimney, Fireplaces, Vents and Solid
Fuel Burning Appliances or Canadian equivalent.
1. Determine termination location based on clearances
provided in Figure 8 and the appropriate termination
spacing shown in Figures 10, 11, 12, 14, and 15.
2. Ensure all vent and air termination remain at least 12"
above ground or normally expected snow
accumulation height.
3. The vent for this appliance shall not terminate
a) Over public walkways; or
b) Near soffit vents or crawl space vents or other
areas where condensate or vapor could creat a
nuisance or hazard or cause poperty damage; or
c) Where condenstae vapor could cause damage or
could be detrimental to the operation of
regulators, relief valves, or other equipment.
4. Do not terminate within 4' horizontally from any
electric meter, gas meter, regulator or any relief
equipment. These distances apply to U.S.
installations. In Canada, the Canadian Fuel Gas
Code takes precedence over this requirement.
5. Vent pipe systems (2 pipe or 1 pipe) termination
clearances will follow the direct vent termination
clearances as shown in Figure 8.
Failure to terminate vent runs above the annual
snow accumulation level may result in nuisance
furnace shutdown and/or hazardous condition that
may lead to bodily harm or loss of life.
20558801 Issue 0442 Page 12 of 32