Goodman GMES80 Series Guide

Service and Troubleshooting


Copyright © 2019-2020 Goodman Manufacturing Company, L.P.
This manual is to be used by qualied, professionally
trained HVAC technicians only. Goodman does not assume
any responsibility for property damage or personal injury
due to improper service procedures or services performed
by an unqualied person.
RS6621003r3
April 2020
®
is a registered trademark of Maytag Corporation or its related companies and is used under license.
All rights reserved.
TABLE OF CONTENTS
IMPORTANT INFORMATION............................................ 2
PRODUCT IDENTIFICATION ........................................... 4
SYSTEM OPERATION...................................................... 6
SCHEDULED MAINTENANCE ....................................... 25
SERVICING..................................................................... 27
ACESSORIES ................................................................. 45
TROUBLESHOOTING CHART ....................................... 48
WIRING DIAGRAMS....................................................... 51
Pride and workmanship go into every product to provide
our customers with quality products. It is possible, however,
that during its lifetime a product may require service.
Products should be serviced only by a qualied service
technician who is familiar with the safety procedures
required in the repair and who is equipped with the proper
tools, parts, testing instruments and the appropriate service
manual. 




















Cancer and Reproductive Harm -
www.P65Warnings.ca.gov
0140M00517-A

IMPORTANT INFORMATION
2




Pride and workmanship go into every product to provide our
customers with quality products. It is possible, however, that
during its lifetime a product may require service. Products
should be serviced only by a qualied service technician who
is familiar with the safety procedures required in the repair
and who is equipped with the proper tools, parts, testing in-
struments and the appropriate service manual. 


OUTSIDE THE U.S., .
(Not a technical assistance line for dealers.) Your telephone company will bill you for the call.


R  RSK  RR  RS JR R 
  SRS RS R SS R R
 QS R RS     S 

 

S

R RSR R
S S 

 R SRS 
 RS

R  S SRR
 RS JRR 

IMPORTANT INFORMATION
3
B10259-216
CO can cause serious illness including permanent brain
damage or death.
Advertencia especial para la instalación de calentadores ó manejadoras
de aire en áreas cerradas como estacionamientos ó cuartos de servicio.
B10259-216
El monóxido de carbono puede causar enfermedades severas
como daño cerebral permanente ó muerte.
Las emisiones de monóxido de carbono pueden circular a través
del aparato cuando se opera en cualquier modo.
B10259-216
RISQUE D'EMPOISONNEMENT AU MONOXYDE DE CARBONE
Cette ventilation est nécessaire pour éviter le danger d'intoxication
au CO pouvant survenir si un appareil produisant du monoxyde
de carbone continue de fonctionner au sein de la zone confinée.

PRODUCT IDENTIFICATION
4

The model and manufacturing number are used for positive identication of component parts used in manufacturing.
Please use these numbers when requesting service or parts information.
* M E S 9 6 0 6 0 3 B N A A
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Brand Minor Revision
A- Amana® G- Goodman® A - Initial Release
V- GMC® B - 1st Revision
Configuration
M - Upflow/Horizontal Major Revision
C - Downflow/Horizontal A - Initial Release
B - 1st Revision
Airflow
C - Variable Speed/ComfortNet Nox
E - High Efficiency Multi Speed N - Natural Gas
S - Single Speed X - Low Nox
Gas Valve Stages Cabinet Width
M - Modulating A - 14"
V - 2 Stage B - 17.5"
S - Single Stage C - 21"
D - 24.5"
AFUE
97 - 97% AFUE Maximum CFM
80 - 80% AFUE 3 - 1200 CFM
92 - 92% AFUE 4 - 1600 CFM
80 - 80% AFUE 5 - 2000 CFM
MBTU/h
040 - 40,000
060 - 60,000
080 - 80,000
Furnace Nomenclature

PRODUCT IDENTIFICATION
5
MODEL # MFG. # 80% GAS FURNACE
AMES800403A*
AMES800603A*
AMES800603B*
AMES800604B*
AMES800803B*
AMES800804B*
AMES800804C*
AMES800805C*
AMES801005C*
AMES801205D*
ACES800403A*
ACES800603A*
ACES800804B*
ACES800805C*
ACES801005C*
*MES800403A*
*MES800603A*
*MES800603B*
*MES800604B*
*MES800803B*
*MES800804B*
*MES800804C*
*MES800805C*
*MES801005C*
*MES801205D*
*MES800403A*
*MES800604B*
*MES800804B*
*MES800805C*
*MES801005C*
*CES800403A*
*CES800603A*
*CES800804B*
*CES800805C*
*CES801005C*
*CES800603A*
*CES800804B*
GMC Brand 80% Down-flow Gas Furnace.
VCES80
ACES80
AMANA Brand 80% Gas Furnace. Multispeed
ECM blower motor. Can be used in downflow or
horizontal positions. Stainless Steel tubular Heat
Exchanger. Comes in A , B & C Cab sizes.
Goodman Brand 80% Gas furnace. Multi-speed ECM
blower motor. Can be installed in Up-flow ,
horizontal Left & right positions. Left or Right side
Gas entry. Alumanized Steel Tubular Heat
Exchanger. Comes in A , B , C & D Cab width sizes.
A = 14"
B = 17.5"
C = 21"
D = 24.5"
GMES80
VMES80
GMC Brand 80% Gas Furnace.
GCES80
Goodman Brand 80% Gas Furnace. Multi-speed ECM
blower motor. Can be used in down-flow or
horizontal positions. Alumanized Steel tubular Heat
Exchanger. Comes in A , B & C Cab sizes.
AMES80
Amana Brand 80% Gas furnace. Multispeed ECM
blower motor. Can be installed in Upflow ,
horizontal Left & right positions. Left or Right side
Gas entry. Stainless Steel Tubular HEat
Exchanger. Comes in A , B , C & D Cab width
sizes.
A = 14"
B = 17.5"
C = 21"
D = 24.5"

SYSTEM OPERATION
6


1. 115 VAC power applied to furnace.
2. Integrated ignition control module performs internal
checks.
3. Integrated ignition control module LED will light.
4. Integrated ignition control monitors safety circuits contin-
uously.
5. Furnace awaits call from thermostat.

1. R and W thermostat contacts close, initiating a call for
heat.
2. Integrated control module performs safety circuit checks.
3. The induced draft blower is energized causing pressure
switch contacts to close. Induced draft blower remains
energized for pre-purge period.
4. Ignitor warm up begins after pre-purge is completed.
5. Gas valve opens at end of ignitor warm up period, deliv-
ering gas to burners to establish ame.
6. The control checks for a signal from the ame sensor
within seven (4) seconds after the gas valve is energized.
Gas will only continue to ow if a ame signal is present.
7. Circulator blower is energized on heat speed following a
xed thirty (30) second blower on delay.
8. Furnace runs, integrated control module monitors safety
circuits continously.
9. R and W thermostat contacts open, allowing the gas valve
to cycle o󰀨.
10. Induced draft blower is de-energized following a fteen
(15) -second post purge.
11. Circulator blower is de-energized following a selectable
heat o󰀨 delay period (90, 120, 150 or 180 seconds).
12. Furnace awaits next call from thermostat.
The adjustable delay-off timing allows the installer to
customize the comfort level.

The normal operational sequence in cooling mode is as
follows:
1. R and Y thermostat contacts close, initiating a call for cool.
2. Integrated control module performs safety circuit checks.
3. Outdoor fan and compressor are energized.
4. Circulator blower is energized on cool speed following a
xed ve (7) second on delay.
5. Furnace circulator blower and outdoor cooling unit
run, integrated control module monitors safety circuits
continuously.
6. R and Y thermostat contacts open, completing the call for
cool.
7. Outdoor fan and compressor are de-energized.
8. Circulator blower is de-energized following a xed forty
ve (65) second cool o󰀨 delay period.
9. Furnace awaits next call from thermostat.

The normal operational sequence in fan only mode is as
follows:
1. R and G thermostat contacts close, initiating a call for fan.
2. Integrated control module performs safety circuit checks.
3. Circulator blower is energized on .
4. Circulator blower runs, integrated control module monitors
safety circuits continuously.
5. R and G thermostat contacts open, completing the call
for fan.
6. Circulator blower is de-energized.
7. Furnace awaits next call from thermostat.

SYSTEM OPERATION
7

The following presents the probable causes of questionable
furnace operation and how to x them. Look through the
observation window in the blower access door and make a
note of the number of ashes in sequence between pauses.
Next, refer to the Troubleshooting Chart on the following
pages for an interpretation of the LED signals and to the
information in this section for a description of the problem.
1.      
Check for voltage to the furnace and low voltage
at the control board. Check for blown fuse on the control
board. If the control determines it has an internal fault, it
enters a locked-out state. Any of the situations mentioned
will cause the diagnostic LED to provide The
control board should only be replaced after all other
checks from the Troubleshooting Chart have been veried.
2. If a ame is not sensed during the rst
seven (4) seconds after the gas valve is energized, the
control turns o󰀨 the gas. There will then be a 30 second
delay while the induced draft blower is energized to purge
the heat exchanger. The ignitor will next be energized
and preheated for (8) seconds. The gas valve will then
be energized. If ame is not sensed in seven (4) seconds
the gas valve will be de-energized and another purge
will occur. The control will cycle the gas valve a total of
three (3) times before it determines it cannot establish
measurable combustion and enters a locked out state.
The diagnostic light code for this problem is 
followed by a longer pause. The control can be reset
and brought out of lockout mode by turning the thermostat
o󰀨 for more than (5) seconds and less than (20) seconds
and then back on. It can also be reset by turning o󰀨 the
electrical disconnect switch to the furnace for a minimum
of 5 seconds.
 The control board will automatically reset one hour
after lockout occurs. If the furnace frequently has to be reset,
it means that a problem exists that should be corrected. Refer
to Troubleshooting Chart on the following pages for aid in
determining the cause.
3. If the control senses the
pressure switch is closed when the induced draft blower
is o󰀨, it waits until the fault is corrected. The diagnostic
light code for this problem is followed
by a longer pause. The probable cause is either a faulty
pressure switch or wiring.
4.  If, after the induced draft
blower is energized, the pressure switch does not close
within 5 minutes, the control will go into a 1-hour lockout.
The control will automatically reset from lockout adn restart
the ignition sequence. The diagnostic light code for this
problem is    followed by a pause.
The probable causes are either disconnected hose to
the pressure switch, faulty pressure switch or wiring, or
restricted air intake or ue piping.
5.    If the limit control opens, the air
circulator blower will be turned on until the limit closes. The
induced draft blower will turn o󰀨 for 5 seconds then turn
o󰀨. The diagnostic light code for this problem is 
followed by a pause. The probable cause is either
low conditioned air ow due to dirty lter or resistance in
duct work, faulty limit, faulty blower, or blower speed set
to low.
6.        If the control
senses a ame when the gas valve is de-energized, it
will run the air circulation blower and the induced draft
blower continuously with no further furnace operation.
The diagnostic ash code for this is a . The
probable causes are either a short to ground in ame
sense circuit, miswiring, lingering burner ame or a slow
closing gas valve.
7.    If the rollout control opens, the
air circulator blower will be energized all the time. The
diagnostic light code for this problem is  
followed by a pause. The probable cause is either
restricted ue piping or improper air requirements.
8.     If the furnace continues to
operate and the micro-amp signal from the ame sensor
falls below specied level, the diagnostic light code for
this problem will be  followed by a pause.
The probable cause is either a coated/oxidized sensor,
incorrectly positioned senser in burner ame or lazy burner
ame due to improper gas pressure or combustion air.
9.     Improperly connected
igniter, bad igniter or poor ground to the equipment. The
diagnostic light code for this problem is .

SYSTEM OPERATION
8

Please adhere to the following warnings and cautions when
installing, adjusting, altering, servicing, or operating the
furnace.
R RS JRR    RR S
JS R SR R  RR  S
 R  SSS R R S 
Q SRSR  R  S SR



S R S R RS  R S 
 SSRS SS R    RK  
S
 

R  SRR S R R
RR R


R SS RR  RS JRR 
  R SK R S   R
 R S R R

 Discharge body’s static electricity before touching
unit. An electrostatic discharge can adversely a󰀨ect electrical
components.
Use the following precautions during furnace installation
and servicing to protect the integrated control module from
damage. By putting the furnace, the control, and the person
at the same electrostatic potential, these steps will help
avoid exposing the integrated control module to electrostatic
discharge. This procedure is applicable to both installed and
uninstalled (ungrounded) furnaces.
1. Disconnect all power to the furnace. Do not touch the
integrated control module or any wire connected to the
control prior to discharging your body’s electrostatic
charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the
furnace near the control. Any tools held in a person’s
hand during grounding will be discharged.
3. Service integrated control module or connecting wiring
following the discharge process in Step 2. Use caution
not to recharge your body with static electricity; (i.e., do
not move or shu󰀪e your feet, do not touch ungrounded
objects, etc.). If you come in contact with an ungrounded
object, repeat Step 2 before touching control or wires.
4. Discharge any static electricity from your body to ground
before removing a new control from its container. Follow
Steps 1 through 3 if installing the control on a furnace.
Return any old or new controls to their containers before
touching any ungrounded object.

This product is designed for use as a residential home gas
furnace. It is  designed or certied for use in mobile home,
trailer, or recreational vehicle applications.
This furnace can be used in the following non-industrial commercial
applications: 󰀩
󰀩In such
applications, the furnace must be installed with the installation
instructions.
Goodman & Amana®80% furnaces are ETL certified
appliances and are appropriate for use with natural or propane
gas. (If using propane gas, a propane conversion kit
is required).

       
         

To ensure proper installation, operation and servicing,
thoroughly read the installation and service manuals
for specics pertaining to the installation, servicing and
application of this product.


SS RR  RS JRR    R
XS SK S S R SK R R
X  RS R RR S RRR
R   S R

R RR  RS JRR    R
  S S R    RRR RR

To ensure proper furnace operation, install, operate, maintain
and service the furnace in accordance with the installation,
operation and service instructions, all local building codes
and ordinances. In their absence, follow the latest edition of
the National Fuel Gas Code (NFPA 54/ANSI Z223.1), and/or
CAN/CGA B149 Installation Codes, local plumbing or waste
water codes, and other applicable codes.
The rated heating capacity of the furnace should be greater
than or equal to the total heat loss of the area to be heated.
The total heat loss should be calculated by an approved
method or in accordance with “ASHRAE Guide” or “Manual
J-Load Calculations” published by the Air Conditioning
Contractors of America.

SYSTEM OPERATION
9


R SS Q  RR  RS
JRR     S S SR
 S  
Follow the instructions listed below when selecting a
furnace location. Refer also to the guidelines provided in the
Combustion and Ventilation Air Requirements section in this
manual or the installation instructions for details.
• Centrally locate the furnace with respect to the proposed
or existing air distribution system.
• Ensure the temperature of the return air entering the
furnace is between 55°F and 100°F when the furnace
is heating.
• If the furnace is installed in an application where the
typical operating sound level of a furnace is deemed
objectionable, an optional sound reduction kit is
available. Consult your local distributor for more details.
• Provide provisions for venting combustion products
outdoors through a proper venting system. Special
consideration should be given to vent/ue pipe routing
and combustion air intake pipe when applicable.
•   All installations must be vented in
accordance with National Fuel Gas Code, NFPA 54/ANSI
Z223.1 - lateset edition. In Canada the furnaces must
be vented in accordance with the National Standard of
Canada, CAN/CGA B149.
• Ensure upow or horizontal furnaces are not installed
directly on carpeting, or any other combustible material.
The only combustible material allowed is wood.
• A special accessory subbase must be used for upright
counterflow unit installations over any combustible
material (including wood). Refer to subbase instructions
for installation details. ( A subbase will not be
required if an air conditioning coil is located beneath
the furnace between the supply air opening and the
combustible oor.
• Exposure to contaminated combustion air will result in
safety and performance-related problems. Do not install
the furnace where the combustion air is exposed to the
following substances:
chlorinated waxes or cleaners
chlorine-based swimming pool chemicals
water softening chemicals
deicing salts or chemicals
carbon tetrachloride
halogen type refrigerants
cleaning solutions (such as perchloroethylene)
printing inks
paint removers
varnishes
hydrochloric acid
cements and glues
antistatic fabric softeners for clothes dryers
and masonry acid washing materials
• Seal o󰀨 a non-direct vent furnace if it is installed near
an area frequently contaminated by any of the above
substances. This protects the non-direct vent furnace
from airborne contaminants. To ensure that the enclosed
non-direct vent furnace has an adequate supply of
combustion air, vent from a nearby uncontaminated
room or from outdoors. Refer to the Combustion and
Ventilation Air Requirements section in this manual or
the installation instructions for details.
• If the furnace is used in connection with a cooling unit,
install the furnace upstream or in parallel with the cooling
unit coil. Premature heat exchanger failure will result if
the cooling unit coil is placed ahead of the furnace.
• If the furnace is installed in a residential garage, position
the furnace so that the burners and ignition source are
located not less than 18 inches (457 mm) above the oor.
Protect the furnace from physical damage by vehicles.
• If the furnace is installed horizontally, the furnace access
doors must be vertical so that the burners re horizontally
into the heat exchanger. Do not install the unit with the
access doors on the “up/top” or “down/bottom” side of
the furnace.

Installations must adhere to the clearances to combustible
materials to which this furnace has been design certied. The
minimum clearance information for this furnace is provided
on the unit’s clearance label. These clearances must be
permanently maintained. Refer to Specication Sheet for
minimum clearances to combustible materials. Clearances
must also accommodate an installation’s gas, electrical, and
drain trap and drain line connections.  In addition to
the required clearances to combustible materials, a minimum
of 24 inches service clearance must be available in front of
the unit.
A furnace installed in a conned space (i.e., a closet or
utility room) must have two ventilation openings with a total
minimum free area of 0.25 square inches per 1,000 BTU/hr of
furnace input rating. One of the ventilation openings must be
within 12 inches of the top; the other opening must be within
12 inches of the bottom of the conned space. In a typical
construction, the clearance between the door and door frame
is usually adequate to satisfy this ventilation requirement.

SYSTEM OPERATION
10

If suspending the furnace from rafters or joist, use 3/8”
threaded rod and 2”x2”x1/8” angle iron as shown in the
following gure. If the furnace is installed in a crawl space it
must also be suspended from the oor joist or supported by
a concrete pad. Never install the furnace on the ground or
allow it to be exposed to water. The length of rod will depend
on the application and the clearances necessary.
PROVIDE 8" MINIMUM CLEARANCE BETWEEN
CENTER ROD AND FURNACE CABINET TO
ALOW FOR CIRCULATOR BLOWER REMOVAL.
ALTERNATE
GAS PIPING
ASSURE FURNACE IS LEVEL FROM
END TO END. ON 90% FURNACES
MAKE SURE THE UNIT HAS A
SLIGHT FORWARD TILT WITH THE
FRONT OF THE FURNACE 0"-3/4"
BELOW THE BACK OF THE
FURNACE.
CONDENSATE
DRAIN
TILT OUTWARD TO ALLOW FOR
DOOR AND CIRCULATOR
BLOWER REMOVAL
POSITION AS CLOSE AS
POSSIBLE TO BLOWER DECK TO
ALLOW FOR CIRCULATOR
BLOWER REMOVAL.
2"x2"x1/8" ANGLE IRON
(3 PLACES)
GAS PIPING
SUPPORT
NUTS
HOLD DOWN
NUTS
3/8" DIAMETER
THREADED ROD
(6 PLACES)


When an existing furnace is removed from a venting
system serving other appliances, the venting system may be
too large to properly vent the remaining attached appliances.
The following vent testing procedure is reproduced from the

     

The following steps shall be followed with each appliance connected
to the venting system placed in operation, while any other appliances
connected to the venting system are not in operation:
a. Seal any unused openings in the venting system;
b. Inspect the venting system for proper size and horizontal pitch,
as required by the National Fuel Gas Code, ANSI Z223.1
or the CSA B149 Installation Codes and these instructions.
Determine that there is no blockage or restriction, leakage,
corrosion and other deciencies which could cause an unsafe
condition;
c. In so 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. 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
shall operate at maximum speed. Do not operate a summer
exhaust fan. Close replace dampers;
d. Follow the lighting instructions. Place the appliance being
inspected in operation. Adjust thermostat so appliance shall
operate continuously;
e. Test for draft hood equipped spillage at the draft hood relief
opening after 5 minutes of main burner operation. Use the
ame of a match or candle;
f. 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, replace dampers
and any other gas burning appliance to their previous
conditions of use;
g. If improper venting is observed during any of the above tests,
the common venting system must be corrected.
Corrections must be in accordance with the latest edition of
the National Fuel Gas Code NFPA 54/ANSI Z223.1 and/or
CSA B149 Installation Codes.
If resizing is required on any portion of the venting system,
use the appropriate table in Appendix G in the latest edition of
the National Fuel Gas Code ANSI Z223.1 and/or CSA B149
Installation Codes.

A high quality single stage thermostat with a common terminal
is recommended.

In an area having good air circulation, locate the thermostat
and dehumidistat (if applicable) about five feet high on
a vibration-free inside wall. Do not install the thermostat
or dehumidistat where it may be inuenced by any of the
following:
• Drafts, or dead spots behind doors, in corners, or under
cabinets.
• Hot or cold air from registers.
• Radiant heat from the sun.
• Light xtures or other appliances.
• Radiant heat from a replace.
• Concealed hot or cold water pipes, or chimneys.
• Unconditioned areas behind the thermostat and
dehumidistat, such as an outside wall.
Consult the instructions packaged with the thermostat and
dehumidistat for mounting instructions and further precautions.




SS RR  RS JRR   R
  R S  R   RSR R RR
S     SSSS RQR
S R  S   R R
Improved construction and additional insulation in buildings
have reduced heat loss by reducing air inltration and escape
around doors and windows. These changes have helped in
reducing heating/cooling costs but have created a problem
supplying combustion and ventilation air for gas red and
other fuel burning appliances. Appliances that pull air out
of the house (clothes dryers, exhaust fans, replaces, etc.)
increase the problem by starving appliances for air.

SYSTEM OPERATION
11
If this furnace is to be installed in the same space with other
gas appliances, such as a water heater, ensure there is an
adequate supply of combustion and ventilation air for the other
appliances. Refer to the latest edition of the National Fuel Gas
Code NFPA 54/ANSI Z223.1 (Section 9.3), or CAN/CGA B149
Installation Codes (Sections 7.2, 7.3, or 7.4), or applicable
provisions of the local building codes for determining the
combustion air requirements for the appliances.
Most homes will require outside air be supplied to the furnace
area by means of ventilation grilles or ducts connecting
directly to the outdoors or spaces open to the outdoors such
as attics or crawl spaces.
The following information on air for combustion and ventilation
is reproduced from the 



 Air for combustion, ventilation, and dilution of ue gases
for appliances installed in buildings shall be obtained by application
of one of the methods covered in 9.3.2 through 9.3.6. Where the
requirements of 9.3.2 are not met, outdoor air shall be introduced in
accordance with methods covered in 9.3.3 through 9.3.6.
Exception No. 1: This provision shall not apply to direct vent ap-
pliances.
Appliances of other than natural draft design and other than
Category 1 vented appliances shall be provided with combustion,
ventilation, and dilution air in accordance with the appliance man-
ufacturer’s instructions.
Appliances shall be located so as not to interfere with proper
circulation of combustion, ventilation, and dilution air.
 Where used, a draft hood or a barometric draft regulator shall
be installed in the same room or enclosure as the appliance served
so as to prevent any di󰀨erence in pressure between the hood or
regulator and the combustion air supply.
 Makeup air requirements for the operation of exhaust fans,
kitchen ventilation systems, clothes dryers, and replaces shall
be considered in determining the adequacy of a space to provide
combustion air requirements.
 The required volume of indoor air
shall be determined in accordance with the method in 9.3.2.1 or
9.3.2.2 except that where the air inltration rate is known to be
less than 0.40 ACH, the method in 9.3.2.2 shall be used. The total
required volume shall be the sum of the required volume calculated
for all appliances located within the space. Rooms communicating
directly with the space in which the appliances are installed through
openings not furnished with doors, and through combustion air open-
ings sized and located in accordance with 9.3.2.3, are considered
a part of the required volume.
The minimum required volume shall be
50 ft 3per 1,000/Btu/hour (4.8m3/kW).
 Where the air inl-
tration rate of a structure is known, the minimum required volume
shall be determined as follows:
(1) For appliances other than fan-assisted, calculate using the
following equation:
21 ft3I
other
Required Volume other > ________ _________
ACH 1000 Btu/hr
(2) For fan-assisted appliances, calculate using the following equation:
15 ft3I
fan
Required Volume fan > ________ _________
ACH 1000 Btu/hr
where:
I
other
= all appliances other than fan-assisted input in Btu per hour
I fan = fan-assisted appliances input in Btu per hour
ACH = air change per hour (percent of volume of space ex-
changed per hour, expressed as a decimal)
(3) For purposes of this calculation, an inltration rate greater than
0.60 ACH shall not be used in the equations in 9.3.2.2(1) and
9.3.2.2(2).
      Openings used to
connect indoor spaces shall be sized and located in accordance
with the following:
(1)* Combining spaces on the same story. Each opening shall have
a minimum free area of 1 in.2/1000Btu/hr (2200 mm2/kW) of the
total input rating of all appliances in the space but not less than
100 in.2(0.60m2). One opening shall commence within 12 in.
(300 mm) of the top, and one opening shall commence within
12 in. (300 mm) of the bottom, of the enclosure [see Figure
A.9.3.2.3(1)]. The minimum dimension of air openings shall be
not less than 3 in. (80 mm).
Furnace
Water
Heater
Opening
Chimney or Gas Vent
Opening








(2) Combining spaces in dierent stories. The volumes of spaces in
di󰀨erent stories shall be considered as communicating spaces
where such spaces are connected by one or more openings in
doors or oors having a total minimum free area of 2 in.2/1000
Btu/hr (4400 mm2/kW) of total input rating of all appliances.
 Outdoor combustion air shall be
provided through opening(s) to the outdoors in accordance with
the methods in 9.3.3.1 or 9.3.3.2. The minimum dimension of air
openings shall not be less than 3 in. (80 mm).

SYSTEM OPERATION
12
Two permanent open-
ings, one commencing within 12 in. (300 mm) of the top and one
commencing within 12 in. (300 mm) of the bottom, of the enclosure
shall be provided. The openings shall communicate directly, or by
ducts, with the outdoors or spaces that freely communicate with the
outdoors, as follows:
(1)* Where directly communicating with the outdoors or where com-
municating to the outdoors through vertical ducts, each opening
shall have a minimum free area of 1 in.2/4000 Btu/hr (550 min2/
kW) of total input rating of all appliances in the enclosure. [See
Figure A.9.3.3.1(1)(a) and Figure A.9.3.3.1(1)(b).]
Furnace
Water
Heater
Outlet Air
Chimney or Gas Vent






Inlet Air
Ventilation louvers for
unheated crawl space
Alternate
air inlet
Ventilation louvers
(each end of attic)



Furnace
Water
Heater
Outlet Air
Chimney or Gas Vent






Inlet air duct
[ends 1 ft (300 mm)
above floor]
Ventilation louvers
(each end of attic)


(2)* Where communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of 1
in.2/2000 Btu/hr (1100 min2/kW) of total input rating of all appli-
ances in the enclosure. [See Figure A.9.3.3.1(2).]
Furnace
Water
Heater
Chimney or Gas Vent






Outlet air duct
Inlet air duct


One permanent open-
ings, commencing within 12 in. (300 mm) of the top of the enclosure,
shall be provided. The appliance shall have clearances of at least
1 in. (25 mm) from the sides and back and 6 in. (150 mm) from the
front of the appliance. The opening shall directly communicate with
the outdoors or shall communicate through a vertical or horizontal
duct to the outdoors or spaces that freely communicate with the
outdoors (see Figure A.9.3.3.2) and shall have a minimum free area
of the following:
(1) 1 in.2/3000 Btu/hr (700 mm2per kW) of the total input rating of
all appliances located in the enclosure, and
(2) Not less than the sum of the areas of all vent connectors in the
space.
Furnace
Water
Heater
Opening
Chimney or Gas Vent







Alternate
Opening
Location


The use
of a combination of indoor and outdoor combustion air shall be in
accordance with (1) through (3) (see example calculation in Annex J]:
(1) Indoor Openings: Where used, openings connecting the interior
spaces shall comply with 9.3.2.3.
(2) Outdoor Opening(s) Location. Outdoor opening(s) shall be
located in accordance with 9.3.3.
(3) Outdoor Opening(s) Size. The outdoor opening(s) size shall be
calculated in accordance with the following:
(a) The ratio of the interior spaces shall be the available vol-
ume of all communicating spaces divided by the required
volume.
(b) The outdoor size reduction factor shall be 1 minus the ratio
of interior spaces.

SYSTEM OPERATION
13
(c) The minimum size of outdoor opening(s) shall be the full
size of outdoor opening(s) calculated in accordance with
9.3.3, multiplied by the reduction factor. The minimum
dimension of air openings shall not be less than 3 in. (80
mm).
Engineered combustion air instal-
lations shall provide an adequate supply of combustion, ventilation,
and dilution air and shall be approved by the authority having
jurisdiction.
Where all combustion
air is provided by a mechanical air supply system, the combustion
air shall be supplied form outdoors at the minimum rate of 0.35 ft3/
min per 1000 Btu/hr (0.034 m3/min per kW) for all appliances located
within the space.
 Where exhaust fans are installed, additional air shall be
provided to replace the exhausted air.
Each of the appliances served shall be interlocked to the
mechanical air supply system to prevent main burner operation
where the mechanical air supply system is not in operation.
 Where combustion air is provided by the building’s me-
chanical ventilation system, the system shall provide the specied
combustion air rate in addition to the required ventilation air.

    The required size of openings for
combustion, ventilation, and dilution air shall be based on the net
free area of each opening. Where the free area through a design
of louver or grille or screen is known, it shall be used in calculating
the size opening required to provide the free area specied. Where
the louver and grille design and free area are not known, it shall be
assumed that wood louvers will have 25 percent free area, and metal
louvers and grilles will have 75 percent free area. Nonmotorized
louvers and grilles shall be xed in the open position.
Screens shall not be smaller
than 1/4 in. mesh.
Motorized louvers shall be interlocked
with the appliance so they are proven in the full open position prior
to main burner ignition and during main burner operation. Means
shall be provided to prevent the main burner form igniting should the
louver fail to open during burner startup and to shut down the main
burner if the louvers close during burner operation.
Combustion air ducts shall comply
with 9.3.8.1 through 9.3.8.8.
Ducts shall be constructed of galvanized steel or a material
having equivalent corrosion resistance, strength, and rigidity.
Exception: Within dwellings units, unobstructed stud and joist spaces
shall not be prohibited from conveying combustion air, provided that
not more than one reblock is removed.
 Ducts shall terminate in an unobstructed space, allowing
free movement of combustion air to the appliances.
Ducts shall serve a single space.
 Ducts shall not serve both upper and lower combustion
air openings where both such openings are used. The separation
between ducts servicing upper and lower combustion air openings
shall be maintained to the source of combustion air.
Ducts shall not be screened where terminating in an attic
space.
Horizontal upper combustion air ducts shall not slope down-
ward toward the source of combustion air.
The remaining space surrounding a chimney liner, gas vent,
special gas vent, or plastic piping installed within a masonry, metal,
or factory built chimney shall not be used to supply combustion air.
Exception: Direct vent appliances designed for installation in a
solid fuel-burning replace where installed in accordance with the
manufacture’s installation instructions.
Combustion air intake openings located on the exterior of
the building shall have the lowest side of the combustion air intake
openings located at least 12 in. (300 mm) vertically from the ad-
joining grade level.



R SS RS JRR   
SX -S S R RR RS S
 R     SRS S
R 
Category I Venting is venting at a non-positive pressure. A
furnace vented as Category I is considered a fan-assisted
appliance and does not have to be “gas tight.”Single-
Stage and Two-Stage gas furnaces with induced draft blowers
draw products of combustion through a heat exchanger
allowing in some instances common venting with natural draft
appliances (i.e. water heaters).
All installations must be vented in accordance with National
Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition. In
Canada, the furnaces must be vented in accordance with the
National Standard of Canada, CAN/CGA B149.1 and CAN/
CGA B149.2 - latest editions and amendments.
 The vertical height of the Category I venting system
must be at least as great as the horizontal length of the
venting system.

R SS  R RS JR 
SX    R RR'S
 R S S  
When an existing furnace is removed from a venting system
serving other appliances, the venting system may be too
large to properly vent the remaining attached appliances. For
complete details refer to Exisiting Furnace Removal section
of this manual.

SYSTEM OPERATION
14
When resizing any portion of the common venting system,
use the appropriate table in Appendix G in the latest edition
of the National Fuel Gas Code NFPA 54/ANSI Z223.1.
Upow or Horizontal units are shipped with the induced
draft blower discharging from the top of the furnace (“Top”
is as viewed for an upow installation). The induced draft
blower can be rotated 90 degrees for Category I venting.
Refer to the following gure. For horizontal installations, a
four inch single wall pipe can be used to extend the induced
draft blower outlet 1/2” beyond the furnace cabinet. Vent the
furnace in accordance with the National Fuel Gas Code NFPA
54/ANSI Z223.1 - latest edition. In Canada, vent the furnace
in accordance with the National Standard of Canada, CAN/
CGA B149.1 and CAN/CGA B149.2 - latest editions and
amendments.

R  R SRS SS   S 
  RS K    RR S 
SKS  SRS S SS R R S  S
  R     R R
Make sure all wires are at least one inch from ue pipe.
Relocate junction box to right side of cabinet if necessary.
Refer to Electrical Connections section of this manual for
instructions.

Wash
Crown
Clay Tile Size: 8" x 8" x12"
(Each x 24" Length)
Clay Tile Size Generally
12" x 12" (24" Length)
1/2" to 1" Air Space
Second Floor
First Floor
Attic Floor
Roof Line
Throat
Damper
Breech
Clean Out
Fan Assisted
Forced Air
Furnace
Natural Draft
Water Heater
Water Heater
Vent Connector
Basement Floor
F.A.F. Vent
Connector


This checklist serves as a summary of the items to be checked
before venting an 80% furnace into a masonry chimney. In
addition, we recommend that a qualied serviceman use
this checklist to perform a yearly inspection of the furnace
venting system.
This checklist is only a summary. For detailed information
on each of the procedures mentioned, see the paragraph
referenced with each item.
This inspection is based upon a draft topical report, “Masonry
Chimney Inspection and Relining”, issued by the Gas
Research Institute. While not yet nalized, we believe this
report represents the best information on this subject which
is currently available.

SYSTEM OPERATION
15
Proper Chimney
Termination?
(Check 1)
Line, terminate with
listed vent cap
(Fix 1)
No
Yes
Chimney channel
free of solid and
liquid fuel
appliances?
(Check 2)
Change venting
arrangements
(Fix 2)
No
Yes
Crown in good
condition
(Check 3)
Rebuild crown
(Fix 3)
and/or Reline
(Fix 4)
Yes
No
Yes
No
No
Reline
(Fix 4)
Reline
(Fix 4)
Cleanout free of
debris?
(Check 4)
Liner in good
condition?
(Check 5)
Yes
Yes
No Reline
(Fix 4)
Dilution air
available?
(Check 6)
Complete the
installation.
(Check 7)

A masonry chimney used as a vent for gas red equipment
must extend at least three feet above the highest point where it
passes through the roof. It must extend at least two feet higher
than any portion of a building within a horizontal distance of
10 feet. In addition, the chimney must terminate at least 3 feet
above any forced air inlet located within 10 feet. The chimney
must extend at least ve feet above the highest connected
equipment draft hood outlet or ue collar.
If the chimney does not meet these termination requirements,
but all other requirements in the checklist can be met, it may
be possible for a mason to extend the chimney. If this will not
be practical, see Fix 1.
2' Min. 2' Min. 3' Min.
10' or Less
Wall or
Parapet
Chimney
Ridge
2' Min.
10' or Less
3' Min.
Chimney
-

Wall or
Parapet
Chimney
: No Height
above parapet
required when distance
from walls or parapet is
more than 10 feet.
More than 10'
3' Min.
Ridge
3' Min.
Chimney
2' Min.
More than 10'
10'
Height above any
roof surface within
10 feet horizontally.




Solid fuel appliances include replaces, wood stoves, coal
furnaces, and incinerators.
Liquid fuel appliances include oil furnaces, oil-red boilers
and oil-red water heaters.
Appliances which burn propane (sometimes referred to
as LP (liqueed petroleum)) gas are considered gas-red
appliances.

SYSTEM OPERATION
16

Damage from condensate usually shows up rst in the crown.
If any of the following trouble signs are present, the condition
of the crown is not satisfactory:
a) Crown leaning
b) Bricks missing
c) Mortar missing
d) Tile liner cracked
e) No tile liner
f) Salt staining at mortar joints. (White stains, and mortar
becomes sandy and/or erodes.)
For problems a, b, or c, see Fix 3. If problems d, e, or f are
present, see Fix 4.  It may be necessary to
follow both Fix 3 and Fix 4.

A cleanout (dropleg) must be present such that the upper
edge of the cleanout cover is at least 12 inches below the
lower edge of the lowest chimney inlet opening.
A chimney without a cleanout could become partially blocked
by debris. If no cleanout is present, the chimney must be
relined (Fix 4).
Remove the cleanout cover, and examine the cleanout for
debris. If signicant amounts of any of the following are found:
• Fuel oil residue
• Bricks
• Mortar or sand
• Pieces of the tile liner
• Rusted pieces of the metallic liner
reline the chimney (Fix 4).

If a metal liner is present, it must be checked. It cannot be
assumed that all existing metal liners are correctly installed
and in good condition.
Remove the lowest existing vent connector, and examine
the inside of the elbow or tee at the base of the liner. A small
amount of soot may be considered acceptable, provided the
installer vacuums it away. If rusted pieces of the liner have
collected here, the metal liner must be removed and replaced
(Fix 4).
Next, gently tap the inside of the liner with a Phillips
screwdriver. If the screwdriver perforates the liner, or if the
tapping does not sound like metal hitting metal, the liner must
be removed and replaced (Fix 4).
Remember that all appliances must be vented inside the liner.
Venting one appliance inside the liner and another appliance
outside the liner is not acceptable.
Next, use a ashlight and small mirror to sight up the liner. B
vent must be supported so as to not come into direct contact
with the chimney walls or tile liner. If it is not, it can probably
be rehung so as to be acceptable. A thimble or re stop may
be helpful here.
Flexible liners should be hung straight or nearly straight. If it
is spiraled in the chimney and in good condition, it should be
rehung. To do this, break the top seal; pull up and cut o󰀨 the
excess liner length, and ret the top seal. Use caution when
doing this, as the cut edges of exible liners may be sharp.
The surfaces of the liner must be physically sound. If gaps
or holes are present, the metal liner must be removed and
replaced (Fix 4).
Finally, conrm that the metal liner is the correct size for the
appliances to be installed. Use the GAMA tables and rules.
If a metal liner is not present, a clay tile liner must be present,
or the chimney must be lined (Fix 4).
Use a ashlight and small mirror at the cleanout or vent
connector to inspect the clay tile liner. If any of the following
problems are present:
• Tile sections misaligned
• Tile sections missing
• Gaps between tile sections
• Signs of condensate drainage at the cleanout or vent
connectors
• Mortar protruding from between tile sections
• Use of sewer pipe or drainage pipe rather than an
approved re clay tile
reline the chimney (Fix 4).
Next, measure the size of the liner. It may be possible to do
this from the cleanout. The liner must be at least as large as
the minimum size established by the tables in National Fuel
Gas Code NFPA 54/ANSI Z223.1 - latest edition and in the
National Standard of Canada, CAN/CGA B149.1 and CAN/
CGA B149.2 - latest editions and amendments. If the liner
is too small or too large, then the chimney must be relined
(Fix 4).

If gas-red appliances are to be vented into a clay tile liner,
a source of dilution air is required.
Dilution air cannot be obtained through:
• Induced draft appliances
• Natural draft appliances with vent dampers
Su󰀩cient dilution air can ordinarily be obtained through the
draft hood of a natural draft appliance only if the appliance’s
vent connector does not include a vent damper.
If dilution air will not be available, the chimney must be relined
(Fix 4).

If Checks 1 through 6 have been satisfactory, and the liner is
an acceptable size as determined by the tables in National
Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition and in
the National Standard of Canada, CAN/CGA B149.1 and CAN/
CGA B149.2 - latest editions and amendments, then the clay
tile liner can probably be used as a vent for the gas appliances.
However, the installer must keep in mind the following factors
which may render the tile liner unsuitable for use as a vent:

SYSTEM OPERATION
17
• Extremely cold weather
• Long vent connectors
• Masonry chimneys with no air gap between the liner and
the bricks. (In practice, this can be di󰀩cult to detect.)
• Exterior chimneys (The tables in National Fuel Gas
Code NFPA 54/ANSI Z223.1 - latest edition and in the
National Standard of Canada, CAN/CGA B149.1 and
CAN/CGA B149.2 - latest editions and amendments
assume interior chimneys.)
If, in the judgment of the local gas utility, installer, and/or local
codes; one or more of the above factors is likely to present a
problem, the chimney must be relined (Fix 4).

Any cap or roof assembly used with a liner must be approved
by the liner manufacturer for such use. The liner and cap/roof
assembly must then terminate above the roof in accordance
with the manufacturer’s instructions.
In some cases, a shorter extension above the roof may be
possible with a liner than would be required with a masonry
chimney.
For further information on relining, see Fix 4.

If the masonry chimney has more than one channel, it may be
possible to vent the gas appliances into one channel and vent
the solid or liquid fuel appliance(s) into another channel(s).
Do not vent an 80% furnace inside of a metal liner with other
appliances vented outside the liner.
Alternatively, the homeowner may agree to discontinue use
of the replace (solid fuel appliance). If so, the tile liner must
be cleaned to remove creosote buildup. The replace opening
must then be permanently sealed.
If oil-fired appliance(s) are being replaced by gas-fired
appliance(s), the tile liner must rst be cleaned to remove
the fuel oil residue.
If none of the above options are practical, the 80% furnace
may need to be vented vertically with B vent.
Under some conditions a 90%+ furnace could be installed
rather than an 80%. The 90% furnace can be vented
horizontally or vertically through PVC pipe.

If the chimney crown is damaged, a qualied mason must
repair it in accordance with nationally recognized building
codes or standards. One such standard which may be
referenced is the Standard for Chimneys, Fireplaces, Vents,
and Solid Fuel Burning Appliances, ANSI/NFPA 211.

Relining options include B vent and exible liners.
If the chimney has diagonal o󰀨sets, B vent probably cannot
be used.
If B vent is to be used, it must be supported adequately.
Supports (such as re stops or thimbles) must be used to
prevent the B vent from coming into direct contact with the tile
liner or chimney walls. Direct contact would result in higher
heat loss, with an increased possibility of poor venting system
performance.
It is not acceptable to vent one appliance inside the B vent
and other appliances outside. The excess space between the
B vent and the chimney walls must be covered at the top of
the chimney by a weatherproof, corrosion resistant ashing.
The B vent should then be topped with a listed vent cap. The
listed vent cap will, when installed per the manufacturer’s
instructions, prevent problems due to rain, birds, or wind
e󰀨ects.
A B vent installed as described in this section is considered to
be an enclosed vent system, and the sizing tables in National
Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition and in
the National Standard of Canada, CAN/CGA B149.1 and CAN/
CGA B149.2 - latest editions and amendments may be used.
If a exible liner is to be used, it must be made of the proper
materials:
• For most residential applications, an aluminum liner
should be acceptable.
• If the combustion air supplied to the furnace will be
contaminated with compounds containing chlorine
or uorine, a liner of AL29-4C stainless steel should
be used. Common sources of chlorine and uorine
compounds include indoor swimming pools and chlorine
bleaches, paint strippers, adhesives, paints, varnishes,
sealers, waxes (which are not yet dried) and solvents
used during construction and remodeling. Various
commercial and industrial processes may also be
sources of chlorine/uorine compounds.
• Heavier gauge 300 and 400 series stainless steel liners
were developed for use with oil or solid fuel appliances.
They are not suitable for use with gas-red appliances.
Flexible liners specically intended and tested for gas
applications are listed in the UL “Gas and Oil Equipment
Directory”. (UL Standard 1777).
For sizing of exible liners, see Note 22 and the tables in the
National Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition
and in the National Standard of Canada, CAN/CGA B149.1
and CAN/CGA B149.2 - latest editions and amendments.
To install the liner, read and follow the liner manufacturer’s
instructions and your local codes. Excess liner length should
be pulled out of the chimney and cut o󰀨. Use caution when
doing this, as the cut edges of exible liners may be sharp.
Do not spiral excess liner inside of the chimney. Support the
liner as recommended by the liner manufacturer.
Some manufacturers of exible liners o󰀨er an insulation
sleeve designed to be added to the liner before it is installed
in the chimney. (Poured insulation, either vermiculite or other
materials, is no longer recommended.) Insulation will need to
be added to the exible liner if:
• •It is required by the liner manufacturer’s instructions.
• •The previous liner was properly sized and installed,
and su󰀨ered from condensation damage.
• •It is required by your local building codes.

SYSTEM OPERATION
18
Even if none of those three conditions exist which require
additional liner insulation, the installer may wish to consider
it if:
• •The local climate is very cold.
• •The chimney is very tall.
• •The vent connectors used are very long or have a large
number of elbows.
• • Local experience indicates that exible liners installed
without insulation are likely to have condensation
problems.
Insulation must be selected and installed in accordance with
the liner manufacturer’s instructions.
Finally, cap the chimney and terminate the liner in accordance
with the liner manufacturer’s instructions.

Horizontal applications, in particular, may dictate many of
the installation’s specics such as airow direction, ductwork
connections, and ue pipe connections.

Furnaces have provisions allowing for electrical and gas
line connections through either side panel. In horizontal
applications the connections can be made either through the
“top” or “bottom” of the furnace.


 SS RR  RS JRR   R 
 RR RS KS R S

 RR KS
S   SRS  RR R R


RSS S RR  Q SR R SR

This furnace is shipped from the factory congured for natural
gas at standard altitude. Propane gas installations require
an orice change to compensate for the energy content
di󰀨erence between natural and propane gas.
High altitude installations may require both a pressure switch
and an orice change. These changes are necessary to
compensate for the natural reduction in the density of both
the gas fuel and the combustion air at higher altitude.
Refer to the Accessories Charts in this manual or product
Specification Sheet for a tabular listing of appropriate
manufacturer’s kits for propane gas and/or high altitude
installations. The indicated kits must be used to insure
safe and proper furnace operation. All conversions must be
performed by a qualied installer, or service agency.


R  SSRS  RS   JRR


R R    SRS   S
S

    R S R S 
R SS  S  S  R  SSR
S RR S KS    SS  RS  SRS
RS JRR    XSR  RS
 R X

The furnace rating plate includes the approved furnace gas
input rating and gas types. The furnace must be equipped
to operate on the type of gas applied. This includes any
conversion kits required for alternate fuels and/or high altitude.

R R R R Q   
S S RSSRS S S    R 
  R S S R S R
Inlet gas supply pressures must be maintained within the
ranges specied below. The supply pressure must be constant
and available with all other household gas red appliances
operating. The minimum gas supply pressure must be
maintained to prevent unreliable ignition. The maximum must
not be exceeded to prevent unit overring.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.


When this furnace is installed at high altitude, the appropriate
High Altitude orice kit must be applied. This is required due
to the natural reduction in the density of both the gas fuel and
combustion air as altitude increases. The kit will provide the
proper design certied input rate within the specied altitude
range.
High altitude kits are purchased according to the installation
altitude and usage of either natural or propane gas. Refer
to the product Specification Sheet or Technical Manual
for a tabular listing of appropriate altitude ranges and
corresponding manufacturer’s high altitude (Natural, Propane
gas, and/or Pressure Switch) kits.
Do  derate the furnace by adjusting the manifold pressure
to a lower pressure than specied on the furnace rating plate.
The combination of the lower air density and a lower manifold
pressure will prohibit the burner orice from drawing the proper
amount of air into the burner. This may cause incomplete
combustion, ashback, and possible yellow tipping.
In some areas the gas supplier may articially derate the gas
in an e󰀨ort to compensate for the e󰀨ects of altitude. If the
gas is articially derated, the appropriate orice size must be
determined based upon the BTU/ft3content of the derated
gas and the altitude. Refer to the National Fuel Gas Code,
NFPA 54/ANSI Z223.1, and information provided by the gas
supplier to determine the proper orice size.

SYSTEM OPERATION
19
A di󰀨erent pressure switch may be required at high altitude
regardless of the BTU/ft3content of the fuel used. Refer to the
product Specication Sheet or Technical Manual for a tabular
listing of appropriate altitude ranges and corresponding
manufacturer’s pressure switch kits.


SS RR  RS JRR   R 
 RR RS KS R S  RR KS
S   SRS  RR R R 
RSS S RR  Q SR R SR

This unit is configured for natural gas. The appropriate
manufacturer’s propane gas conversion kit, must be applied
for propane gas installations.
• • Single-stage 80% furnace modelsusing a Honeywell
VR8215 single stage valve or a White-Rodgers 36J22
use LPT-03 LP Conversion Kit.
Refer to the specification sheet for the model you are
servicing. Refer to the “propane gas and/or High Altitude
Installations” section for details.

This unit is equipped with a 24 volt gas valve controlled
during furnace operation by the integrated control module.
As shipped, the valve is congured for natural gas. The valve
is eld convertible for use with propane gas by using the
appropriate propane gas conversion kit. Taps for measuring
the gas supply pressure and manifold pressure are provided
on the valve.
       



The gas valve has a manual ON/OFF control located on
the valve itself. This control may be set only to the “ON” or
“OFF” position. Refer to the Lighting Instructions Label or the
“Putting the Furnace Into Operation” section of this manual or
the installation instructions for use of this control during start
up and shut down periods.


 SS SSRR R Q 
  RR  Q S RR S 
RR S    R  R 
RK   R
The gas piping supplying the furnace must be properly sized
based on the gas ow required, specic gravity of the gas,
and length of the run. The gas line installation must comply
with local codes, or in their absence, with the latest edition of
the National Fuel Gas Code, NFPA 54/ANSI Z223.1.
Length of Nominal Black Pipe Size
Pipe in Feet 1/2" 3/4" 1" 1 1/4" 1 1/2"
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 980
40 63 130 245 500 760
50 56 115 215 440 670
60 50 105 195 400 610
70 46 96 180 370 560
80 43 90 170 350 530
90 40 84 160 320 490
100 38 79 150 305 460
CFH =
(Pressure 0.5 psig or less and pressure drop of 0.3" W.C.; Based on 0.60 Specific
Gravity Gas)


BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
To connect the furnace to the building’s gas piping, the installer
must supply a ground joint union, drip leg, manual shuto󰀨
valve, and line and ttings to connect to gas valve. In some
cases, the installer may also need to supply a transition piece
from 1/2” pipe to a larger pipe size.
The following stipulations apply when connecting gas piping.
Refer to the following gures for typical gas line connections
to the furnace.
1. Use black iron or steel pipe and ttings for the building
piping.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
3. Use ground joint unions.
4. Install a drip leg to trap dirt and moisture before it can
enter the gas valve. The drip leg must be a minimum of
three inches long.
5. Install a 1/8” NPT pipe plug tting, accessible for test
gage connection, immediately upstream of the gas
supply connection to the furnace.
6. Use two pipe wrenches when making connection to
the gas valve to keep it from turning. The orientation of
the gas valve on the manifold must be maintained as
shipped from the factory.
7. Install a manual shuto󰀨 valve between the gas meter
and unit within six feet of the unit. If a union is installed,
the union must be downstream of the manual shuto󰀨
valve, between the shuto󰀨 valve and the furnace.
8. Tighten all joints securely.
9. Connect the furnace to the building piping by one of the
following methods:
• – Rigid metallic pipe and ttings.
• – Semi-rigid metallic tubing and metallic fittings.
Aluminum alloy tubing must not be used in exterior
locations. In order to seal the grommet cabinet
penetration, rigid pipe must be used to reach the outside
of the cabinet. A semi-rigid connector to the gas piping
may be used from there.

SYSTEM OPERATION
20
10. Use listed gas appliance connectors in accordance with
their instructions. Connectors must be fully in the same
room as the furnace.
11. Protect connectors and semi-rigid tubing against physical
and thermal damage when installed. Ensure aluminum-
alloy tubing and connectors are coated to protect against
external corrosion when in contact with masonry, plaster,
or insulation, or subjected to repeated wetting by liquids
such as water (except rain water), detergents, or sewage.


S  S  S   SR

SS R
 R  S

Before placing unit in operation, leak test the unit and gas
connections.

  SS  XS R R R S
R    SR KS
Check for leaks using an approved chloride-free soap and
water solution, an electronic combustible gas detector, or
other approved testing methods.
 Never exceed specied pressures for testing. Higher
pressure may damage the gas valve and cause subsequent
overring, resulting in heat exchanger failure. Disconnect
this unit and shuto󰀨 valve from the gas supply piping system
before pressure testing the supply piping system with
pressures in excess of 1/2 psig (3.48 kPa). Isolate this unit
from the gas supply piping system by closing its external
manual gas shuto󰀨 valve before pressure testing supply
piping system with test pressures equal to or less than 1/2
psig (3.48 kPa).



R S S R  R   K S  S 
  RS R  SS

R RR 
RS JR R    RR XS S  
R S KS S  R 
A gas detecting warning system is the only reliable way to
detect a propane gas leak. Iron oxide (rust) can reduce the
level of odorant in propane gas. Do not rely on your sense of
smell. Contact a local propane gas supplier about installing
a gas detecting warning system. If the presence of gas is
suspected, follow the instructions on this page.
All propane gas equipment must conform to the safety
standards of the National Board of Fire Underwriters, NBFU
Manual 58.
For satisfactory operation, propane gas pressure must be
11 inch WC at the furnace manifold with all gas appliances
in operation. Maintaining proper gas pressure depends on
three main factors:
1. Vaporization rate, depending on temperature of the liquid,
and “wetted surface” area of the container or containers.
2. Proper pressure regulation. (Two-stage regulation is
recommended for both cost and e󰀩ciency).
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size
will depend on length of pipe run and total load of all
appliances.
Complete information regarding tank sizing for vaporiza-
tion, recommended regulator settings, and pipe sizing is
available from most regulator manufacturers and propane
gas suppliers.
Always use a pipe sealant approved for natural gas and LP
gas.
Refer to the following illustration for typical propane gas
installations and piping.



 







 S R S S  S  X
R R  S  S SR R 
 R SR  S S 
R   S S K
• S R S S R  R K S 
S    RS R  SS
• R S R   K  S 
X  R 