Carrier 58UXT Series Instructions and recipes

58UXT
Upflow/Horizontal, 2-Speed, 2-Stage
Induced-Combustion Gas Furnace
Installation, Start-Up, and Operating Instructions
Size 060-120, Series 100
NOTE: Read the entire instruction manual before starting the
installation.
Index Page
SAFETY CONSIDERATIONS..................................................1-2
Clearances to Combustibles......................................................1
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
PROCEDURE........................................................................2-3
Dimensional Drawing ....................................................................2
INTRODUCTION..........................................................................3
LOCATION....................................................................................3
General......................................................................................3
Location Relative to Cooling Equipment ................................3
Hazardous Locations.................................................................4
AIR FOR COMBUSTION AND VENTILATION...................4-5
Unconfined Space.....................................................................4
Confined Space......................................................................4-5
UPFLOW INSTALLATION .........................................................5
HORIZONTAL ATTIC INSTALLATION...................................5
HOROZONTAL CRAWLSPACE INSTALLATION...............5-6
FILTER ARRANGEMENT...........................................................6
LEVELING LEGS (IF REQUIRED)............................................6
GAS PIPING...............................................................................6-7
ELECTRICAL CONNECTIONS...............................................8-9
115-v Wiring..........................................................................8-9
24-v Wiring...............................................................................9
Accessories................................................................................9
VENTING ......................................................................................9
START-UP, ADJUSTMENT, AND
SAFETY CHECK................................................................9-18
General......................................................................................9
Sequence of Operation........................................................9-13
Adaptive Heating Mode....................................................10-11
Non-Adaptive Heating Mode............................................11-12
Cooling Mode .........................................................................12
Continuous Blower Mode.......................................................12
Heat Pump Mode...............................................................12-13
Defrost.....................................................................................13
Start-Up Procedures...........................................................13-14
Adjustments .......................................................................14-17
Set Gas Input Rate ............................................................14-16
Set Temperature Rise........................................................16-17
Set Thermostat Heat Anticipator ......................................17-18
Check Safety Controls............................................................18
Checklist..................................................................................18
SAFETY CONSIDERATIONS
Installation and servicing of heating equipment can be hazardous
due to gas and electrical components. Only trained and qualified
personnel should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions
such as cleaning and replacing air filters. All other operations must
be performed by trained service personnel. When working on
heating equipment, observe precautions in the literature, on tags,
and on labels attached to or shipped with the unit and other safety
precautions that may apply.
Follow all safety codes. In the United States, refer to the National
Fuel Gas Code (NFGC) NFPA No. 54-1992/ANSI Z223.1-1992.
In Canada, refer to the current edition of the National Standard of
®ama
CANADIAN GAS ASSOCIATION
APPROVED
R
Table 1—Minimum Clearances To Combustible
Materials (In.)
UNIT SIZE 060 080—120
UPFLOW
Furnace Sides Single-Wall Vent 1 0
Type B-1 Double-Wall Vent 0 0
Furnace Back 00
Plenum Top 11
Furnace Front (See Notes) Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 3 3
Vent Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 1 1
HORIZONTAL POSITION (IN ALCOVE, ATTIC,
AND CRAWLSPACE)
Sides* 11
Back 00
Top Single-Wall Vent 1 1
Type B-1 Double-Wall Vent 1 1
Furnace Front† (See Notes) Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 3 3
Vent Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 1 1
HORIZONTAL POSITION (IN CLOSET)**
Sides*‡ 11
Back 00
Top Single-Wall Vent 2 2
Type B-1 Double-Wall Vent 2 2
Furnace Front
(See Notes) Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 3 3
Vent Single-Wall Vent 6 6
Type B-1 Double-Wall Vent 1 1
* Supply side must maintain 6 in. clearance from flue to combustible materials
when using single-wall vent.
† 18 in. front clearance required for alcove.
‡ Indicates supply or return sides when furnace is in horizontal position. Line
contact only permissible between lines formed by intersections of top and two
sides of furnace jacket, building joists, studs, or framing. Clearance to return
side is 0 in.
** J-Box must be installed on lower (bottom) inside of furnace.
NOTES:
1. Provide 30-In. front clearance for servicing. An open door in front of furnace
can meet this requirement.
2. A minimum clearance of 3 In. must be provided in front of furnace for
combustion air and proper operation.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 6a 8a PC 101 Catalog No. 535-847 Printed in U.S.A. Form 58UXT-1SI Pg 1 7-95 Replaces: New
→

Canada CAN/CGA- B149.1- and .2-M91 Natural Gas and Propane
Installation Codes Amendment No. 1 and (NSCNGPIC). Wear
safety glasses and work gloves. Have fire extinguisher available
during start-up and adjustment procedures and service calls.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on the furnace and in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies a hazard which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage.
These instructions cover minimum requirements and conform to
existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing residen-
tial construction practices. We require these instructions as a
minimum for a safe installation.
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
PROCEDURE
Electrostatic discharge can affect electronic components.
Take precautions during furnace installation and servicing to
protect the furnace electronic control. Precautions will pre-
vent electrostatic discharges from personnel and hand tools
which are held during the procedure. These precautions will
help to avoid exposing the control to electrostatic discharge
by putting the furnace, the control, and the person at the same
electrostatic potential.
1. Disconnect all power to the furnace. DO NOT TOUCH THE
CONTROL OR ANY WIRE CONNECTED TO THE CON-
TROL PRIOR TO DISCHARGING YOUR BODY’S ELEC-
TROSTATIC CHARGE TO GROUND.
2. Firmly touch a clean, unpainted, metal surface of the furnace
chassis which is close to the control. Tools held in a person’s
hand during grounding will be satisfactorily discharged.
3. After touching the chassis you may proceed to service the
control or connecting wires as long as you do nothing that
recharges your body with static electricity (for example; DO
Table 2—Dimensions (In.)
UNIT SIZE A D E FLUE COLLAR SHIP. WT(LB)
060-12 14-3/16 12-9/16 12-11/16 4 134
080-16 21 19-3/8 19-1/2 4 154
100-16 21 19-3/8 19-1/2 4 166
100-20 24-1/2 22-7/8 23 4 184
120-20 24-1/2 22-7/8 23 5 194
Fig. 1—Dimensional Drawing A88367
A
D13⁄16″
E11⁄16″
11⁄16″
28 1⁄2″
39 7⁄8″
24 5⁄16″
11⁄16″3″
2 1⁄16″
1″
12 5⁄16″
5 3⁄8″
5 13⁄16″
2 3⁄8″
AIR INLET
7⁄8-IN. DIA HOLE
POWER ENTRY
7⁄8-IN. DIA
ACCESSORY
1 3⁄4-IN.DIA HOLE
GAS ENTRY
1⁄2-IN. DIA HOLE
THERMOSTAT
WIRE ENTRY
SIDE INLET
FLUE COLLAR
NOTE:
Minimum return-air opening at furnace:
1. For 800 CFM–16-In. round or 141⁄2x 12-In. rectangle.
2. For 1200 CFM–20-In. round or 141⁄2x 191⁄2-In. rectangle.
3. For 1600 CFM–22-In. round or 141⁄2x 231⁄4-In. rectangle.
4. For airflow requirements above 1800 CFM, use both side inlets,
a combination of 1 side inlet and the bottom, or the bottom only.
2 additional 7⁄8In. Dia knockouts are located in the top plate.
NOTES:
5 3⁄8″
5 13⁄16″
2 3⁄8″
2 11⁄16″
1″
2 1⁄16″19″
13⁄16″
7⁄8-IN. DIA
POWER ENTRY
AIRFLOW
OUTLET
1 1⁄2-IN.DIA
R.H. GAS ENTRY
7⁄8-IN. DIA ACCESSORY
1⁄2-IN. DIA THERMOSTAT
WIRE ENTRY
SIDE INLET 141⁄2″
1″
231⁄4″
SIDE RETURN
DUCT LOCATION
13⁄4″
TYP 1″
5⁄8″
TYP
2

NOT move or shuffle your feet, DO NOT touch ungrounded
objects, etc.).
4. If you touch ungrounded objects (recharge your body with
static electricity), firmly touch furnace again before touching
control or wires.
5. Use this procedure for installed and uninstalled (ungrounded)
furnaces.
6. Before removing a new control from its container, discharge
your body’s electrostatic charge to ground to protect the
control from damage. If the control is to be installed in a
furnace, follow items 1. through 5. before bringing the control
or yourself into contact with the furnace. Put all used AND
new controls into containers before touching ungrounded
objects.
7. An ESD service kit (available from commercial sources) may
also be used to prevent ESD damage.
INTRODUCTION
The model 58UXT Series 100 Furnace is available in sizes 60,000
through 120,000 Btuh input capacities.
The design of the upflow/horizontal gas-fired furnace is A.G.A.
and C.G.A. design-certified for use with natural and propane gases
and for installation on combustible wood flooring, in alcoves,
attics, basements, closets, or utility rooms. The design of this
furnace line is not A.G.A. and C.G.A. design-certified for instal-
lation in mobile homes, recreation vehicles, or outdoors.
Before installing the furnace, refer to the current edition of the
NFGC. Canadian installations must be installed in accordance with
NSCNGPIC and all authorities having jurisdiction. For further
information, the NFGC is available from National Fire Protection
Association Inc. Batterymarch Park, Quincy, MA 02269; Ameri-
can Gas Association, 1515 Wilson Boulevard, Arlington, VA
22209; or from Literature Distribution.
Installation must conform to the regulations of the serving gas
supplier and the local building, heating, and plumbing codes in
effect in the area in which the installation is made, or in the
absence of local codes with the requirements of the NFGC.
Application of this furnace should be indoors with special
attention given to vent sizing and material, gas input rate, air
temperature rise, and unit sizing. Improper installation or
misapplication of the furnace can require excessive servicing
or cause premature component failure.
This furnace is designed for a 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
temperature must not exceed 85°F db.
To aid in installation, troubleshooting, and service, a status code
label is located on the blower compartment door. This label
explains how to use the LED status indicator on the furnace control
which is viewed through the sight glass on the door.
Improper installation, adjustment, alteration, service, mainte-
nance, or use can cause carbon monoxide poisoning, explo-
sion, fire, electrical shock, or other conditions which may
cause personal injury or property damage. Consult a qualified
installer, service agency, local gas supplier, or your distribu-
tor or branch for information or assistance. The qualified
installer or agency must use only factory-authorized and
listed kits or accessories when modifying this product. A
failure to follow this warning can cause electrical shock, fire,
personal injury, or death.
For high-altitude installations, the high-altitude conversion kit
MUST be installed at or above 5500 ft above sea level.
For accessory installation details, refer to the applicable installa-
tion literature.
NOTE: Remove all shipping brackets and materials before oper-
ating the furnace.
Step 1—Location
GENERAL
Do not install furnace in a corrosive or contaminated atmo-
sphere. Make sure all combustion and circulating air require-
ments are met.
Do not use this furnace during construction when adhesives,
sealers, and/or new carpets are being installed and curing. If
the furnace is required during construction, use clean outside
air for combustion and ventilation. Compounds of chlorine
and fluorine, when burned in combustion air, form acids
which will cause corrosion of the heat exchangers and metal
vent system. Some of these compounds are released from
paneling and dry wall adhesives, paints, thinners, masonry
cleaning materials, and many other solvents commonly used
in the construction process.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
This furnace must be installed so the electrical components are
protected from water.
Locate the furnace as near the center of the air distribution system
and chimney or vent as possible. The furnace should be installed
as level as possible. When a furnace is installed so that the supply
ducts carry air to areas outside the space containing the furnace,
the return air must also be handled by a duct(s) sealed to the
furnace casing and terminating outside the space containing the
furnace.
Provide ample space for servicing and cleaning. Always comply
with the minimum fire protection clearances shown on the unit
clearance label. This furnace shall not be installed directly on
carpeting, tile, or any combustible material other than wood
flooring.
LOCATION RELATIVE TO COOLING EQUIPMENT
The cooling coil must be installed parallel with or on the
downstream side of the furnace to avoid condensation in the heat
exchangers. When installed parallel with a furnace, dampers or
other means used to control the flow of air must prevent chilled air
from entering the furnace. If the dampers are manually operated,
they must be equipped with means to prevent operation of either
unit unless the damper is in the full-heat or full-cool position.
3

HAZARDOUS LOCATIONS
When the furnace is installed in a residential garage, it must be
installed so that the burners and ignition source are located at least
18 in. above the floor. The furnace should be protected from
physical damage by vehicles. When a furnace is installed in public
garages, airplane hangars, or other buildings having hazardous
atmospheres, the unit must be installed in accordance with the
recommended good practice requirements of the National Fire
Protection Association, Inc.
Step 2—Air for Combustion and Ventilation
Provisions for adequate combustion and ventilation air must be
provided in accordance with Section 5.3, Air for Combustion and
Ventilation, of the NFGC or applicable provisions of the local
building codes.
Canadian installations must be in accordance with Section 7 of the
NSCNGPIC and all authorities having jurisdiction.
Air for combustion must not be contaminated by halogen
compounds, which include fluoride, chloride, bromide, and
iodide. These elements are found in aerosol sprays, deter-
gents, bleaches, cleaning solvents, salts, air fresheners, and
other household products.
All fuel-burning equipment must be supplied with air for combus-
tion of the fuel. Sufficient air MUST be provided to ensure there
will not be a negative pressure in the equipment room or space. In
addition, a positive seal MUST be made between the furnace
cabinet and the return-air duct to prevent pulling air from the
burner area and draft safeguard opening into the circulating air.
The operation of exhaust fans, kitchen ventilation fans,
clothes dryers, or fireplaces could create a negative air
pressure condition at the furnace. Make-up air must be
provided for these devices, in addition to that required by the
furnace.
The requirements for combustion and ventilation air depend upon
whether the furnace is located in a CONFINED or UNCONFINED
space.
UNCONFINED SPACE
An unconfined space must have at least 50 cu ft for each 1000
Btuh of total input for all the appliances (such as furnaces, clothes
dryers, water heaters, etc.) in the space.
For Example:
58UXT FURNACE HIGH-STAGE
INPUT BTUH MINIMUM SQ FT WITH 7-1/2 FT CEILING
60,000 400
80,000 534
100,000 667
117,000 780
If the unconfined space is of unusually tight construction, air for
combustion and ventilation MUST come from either the outdoors
or spaces freely communicating with the outdoors. Combustion
and ventilation openings must be sized the same as for a confined
space as defined below. Return air must not be taken from the
room unless an equal or greater amount of air is supplied to the
room.
CONFINED SPACE
A confined space has volume less than 50 cu ft per 1000 Btuh of
the total input rating for all appliances installed in that space. A
confined space MUST have 2 permanent openings, 1 within 12 in.
of the ceiling, and the other within 12 in. of the floor which freely
communicate with an unconfined space or the outdoors. (See Fig.
2.)
NOTE: In determining the free area of an opening, the blocking
effect of the louvers, grilles, and screens must be considered. If the
free area of a louver or grille design is unknown, it may be
assumed that wood louvers have a 20 percent free area, and metal
louvers or grilles have a 60 percent free area. Screens, when used,
must not be smaller than 1/4-in. mesh. Louvers and grilles must be
constructed so they cannot be closed.
The size of the openings depends upon whether the air comes from
outside of the structure or an unconfined space inside the structure.
1. All air from inside the structure:
a. Each opening MUST have at least 1 sq in. of free area per
1000 Btuh of the total input for all equipment within the
confined space, but not less than 100 sq in. per opening.
(See Fig. 2.) The minimum dimension of air openings shall
be not less than 3 in.
For Example:
COMBUSTION AIR FROM UNCONFINED SPACE
58UXT Furnace
High-Stage
Input Btuh
Free Area per Opening
(Sq In.)
60,000 100
80,000 100
100,000 100
117,000 117
b. If the building is constructed unusually tight, a permanent
opening directly communicating with the outdoors should
be provided. This opening shall have a minimum free area
of 1 sq in. per 4000 Btuh of total input rating for all
equipment in the enclosure. (See Fig. 3.)
c. If the furnace is installed on a raised platform to provide a
return-air plenum, and return air is taken directly from the
hallway or space adjacent to the furnace, all air for
combustion must come from outdoors. (See Fig. 3.)
2. All air from outside the structure:
a. If combustion air is taken from outdoors through vertical
ducts, the openings and ducts MUST have at least 1 sq in.
of free area per 4000 Btuh of the total input for all
equipment within the confined space. (See Fig. 3.)
For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
VERTICAL DUCTS
58UXT Furnace
High-Stage
Input Btuh
Free Area per Opening
(Sq In.) Round Pipe (In. Dia)
60,000 15.0 5
80,000 20.0 6
100,000 25.0 6
117,000 29.3 7
b. If combustion air is taken from the outdoors through
horizontal ducts, the openings and ducts MUST have at
least 1 sq in. of free area per 2000 Btuh of the total input
for all equipment within the confined space. (See Fig. 3.)
4

For Example:
COMBUSTION AIR FROM OUTDOORS THROUGH
HORIZONTAL DUCTS
58UXT Furnace
High-Stage
Input Btuh
Free Area per Opening
(Sq In.) Round Pipe (In. Dia)
60,000 30.0 7
80,000 40.0 8
100,000 50.0 8
117,000 58.5 9
c. When ducts are used, they must be of the same cross-
sectional area as the free area of the openings to which they
connect. The minimum dimension of ducts must not be less
than 3 in. (See Fig. 3.)
Step 3—Upflow Installation
Do not install the furnace on its back or sides. Safety control
operation will be adversely affected. Never connect return-air
ducts to the back of the furnace. A failure to follow this
warning can cause a fire, personal injury, or death.
NOTE: Door clip on control door may be removed for upflow
installation.
1. Position furnace in desired location.
2. Connect gas supply pipe.
3. Connect supply- and return-air ducts.
Step 4—Horizontal Attic Installation
Do not install the furnace on its back or sides. Safety control
operation will be adversely affected. Never connect return-air
ducts to the back of the furnace. A failure to follow this
warning can cause a fire, personal injury, or death.
The furnace can be installed horizontally with either the left-hand
(LH) or right-hand (RH) side down. A typical attic installation is
shown in Fig. 4.
CONSTRUCT A WORKING PLATFORM
Construct working platform on location where all required furnace
clearances are met. (See Table 1 and Fig. 4.)
INSTALL FURNACE
1. Position furnace in desired location.
2. Connect gas supply pipe. See Fig. 4 for typical piping entry.
3. Connect supply- and return-air ducts.
4. Install 24- X 24-in. sheet metal shield on platform in front of
louvered control panel as shown in Fig. 4.
Step 5—Horizontal Crawlspace Installation
The furnace can be installed horizontally with either LH or RH
side up. In a crawlspace, the furnace can either be hung from the
floor joist (See Fig. 5) or installed on suitable blocks or pad (See
Fig. 6.) The furnace can be suspended from each corner by hanger
bolts (4 each 3/8 in. all thread rod) cut to desired length, 1- X
3/8-in. flat washer, 3/8-in. lockwasher, and 3/8-in. nut. Dimples
are provided for hole locations. (See Fig. 1.)
Since the horizontal crawlspace installation is very similar to the
attic, refer to Horizontal Attic Installation. The installation of a
Fig. 2—Confined Space: Air for Combustion and
Ventilation from an Unconfined Space
A89012
SUPPLY
AIR
6″MIN
(FRONT) †
RETURN AIR
VENT THROUGH ROOF
1 SQ IN.
PER 1000
BTUH*IN DOOR
OR WALL
12″MAX
1 SQ IN.
PER 1000
BTUH*IN DOOR
OR WALL
12″MAX
INTERIOR
HEATED
SPACE
* Minimum opening size is 100 square in. with
minimum dimensions of 3-In.
† Minimum of 3-In. when type-B1 vent is used.
UNCONFINED
SPACE
CONFINED SPACE
Fig. 3—Confined Space: Air for Combustion and
Ventilation from Outdoors
A89013
1 SQ IN.
PER
4000
BTUH*
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH*
SUPPLY
AIR
VENT
THROUGH
ROOF
D
B
A
C
E
1 SQ IN.
PER 4000
BTUH*
DUCT
TO
OUTDOORS
RETURN AIR
1 SQ IN.
PER 2000
BTUH*
1 SQ IN.
PER 2000
BTUH*
DUCTS
TO
OUTDOORS
12″MAX
12″MAX 12″MAX
Use any of the following
combinations of openings:
A & B C & D D & E F & G
NOTE:
*Minimum dimensions of 3-In.
CONFINED SPACE
12″
MAX
12″
MAX
OUTDOORS
1 SQ IN.
PER
4000
BTUH*
F
G
5

sheet metal shield in front of the louvered control panel is covered
in Horizontal Attic Installation. For a crawlspace installation, this
same sheet metal shield must be installed above the louvered
control panel. Extend the sheet metal shield over furnace top far
enough to cover gas pipe entry hole.
Step 6—Filter Arrangement
Never operate unit without a filter or with filter access door
removed. A failure to follow this warning can cause a fire,
personal injury, or death.
The factory-supplied filter(s) is shipped in the blower compart-
ment. Determine location for the filter and move filter retaining
hardware, if necessary, before attaching the return-air duct. After
the return-air duct has been connected to the furnace, install the
filter(s) inside the furnace blower compartment. See Fig. 7 for side
return application and Fig. 8 for bottom return application.
A bottom closure panel is factory installed in the bottom of the
furnace. When bottom return inlet is desired, remove and discard
the enclosure panel.
Filter retaining brackets, supports, and retainers are factory as-
sembled and shipped installed for side return application, with 1
set of all required hardware on each furnace. (See Fig. 7.)
For bottom return applications, remove the front and back brackets
and supports from each side. The back bracket(s) are installed in
the rear of the furnace casing. Dimples are provided to mark
mounting screw locations.
The front bracket(s) are installed on the bottom front plate, as
shown in Fig. 8, once the bottom enclosure has been removed.
Rotate filter supports 180° so filter will rest on support and
reinstall. Install small U-shaped end of filter retaining rod in the
rear bracket. Install the front of filter retainer rod as shown in Fig.
8. Two sets of hardware are needed for furnaces in 24-1/2 in.
casings using 2 filters for bottom return. All hardware is provided
for filter installation.
Step 7—Leveling Legs (If Required)
When the furnace is used with side inlet(s) and leveling legs are
required, refer to Fig. 9 and install field-supplied, corrosion-
resistant 5/16-in. machine bolts and nuts.
NOTE: The length of the bolt should not exceed 1-1/2 in.
1. Lay furnace on its back. Locate and drill 5/16-in. diameter
hole in each bottom corner of furnace as shown in Fig. 9.
2. Install nut on bolt and install bolt with nut in hole. (Install flat
washer if desired.)
3. Install another nut on other side of furnace base. (Install flat
washer if desired.)
4. Adjust outside nut to provide desired height and tighten inside
nut to secure arrangement.
Step 8—Gas Piping
Emissions control devices located at heat exchanger inlets
MUST be removed for propane installations. (Refer to gas
conversion kit for instructions.)
Gas piping must be installed in accordance with national and local
codes. Refer to the NFGC in U.S. Canadian installations must be
installed in accordance with NSCNGPIC and all authorities having
jurisdiction.
The gas supply line should be a separate line running directly from
the gas meter to the furnace, if possible. Refer to Table 4 for the
recommended gas pipe size. Risers must be used to connect to the
furnace and the meter.
If a flexible connector is required or allowed by the authority
having jurisdiction, black iron pipe shall be installed at
furnace gas control valve and extend a minimum of 2 in.
outside the furnace casing. A failure to follow this warning
could result in fire, personal injury, or death.
Piping should be pressure tested in accordance with local and
national plumbing and gas codes BEFORE the furnace has been
attached. If the test pressure exceeds 0.5 psig (14-in. wc), the gas
supply pipe must be disconnected from the furnace and capped
before the pressure test. If the test pressure is equal to or less than
0.5 psig (14-in. wc), close the manual shut-off valve before the
Fig. 4—Horizontal Attic Installation A95233
30-IN. MIN
WORK AREA
6″ MIN
FLUE VENT
GAS
ENTRY MANUAL SHUTOFF
GAS VALVE
24 ″
24 ″
SHEET
METAL
SEDIMENT TRAP
LINE CONTACT ONLY PERMISSIBLE BETWEEN
LINES FORMED BY INTERSECTIONS OF
THE TOP AND TWO SIDES OF THE FURNACE
JACKET, BUILDING JOISTS,
STUDS, OR FRAMING.
CLEARANCE
TO COMBUSTABLE
MATERIALS
6

test. (See Fig.10.) It is recommended that the ground joint union be
loosened before pressure testing. After all connections have been
made, purge the lines and check for leakage with regulated gas
supply pressure.
Install a sediment trap in the riser leading to the furnace. The trap
can be installed by connecting a tee to the riser leading from the
furnace. Connect a capped nipple into the lower end of the tee. The
capped nipple should extend below the level of the gas controls.
(See Fig. 10.)
Apply joint compound (pipe dope) sparingly and only to the male
threads of each joint. The compound must be resistant to the action
of propane gas.
Install an accessible manual shut-off valve upstream of the furnace
gas controls and within 72 in. of the furnace. A 1/8-in. NPT
plugged tapping is provided on the gas valve for test gage
connection. Installation of an additional 1/8-in. NPT plugged
tapping, accessible for test gage connection, installed immediately
upstream of the gas supply connection to the furnace and down-
stream of the manual shut-off valve, is not required. Place ground
joint union between the gas control manifold and the manual
shut-off valve.
Use the proper length of pipes to avoid stress on the gas
control manifold. A failure to follow this warning can cause
a gas leak resulting in a fire, explosion, personal injury, or
death.
Fig. 5—Crawlspace Horizontal Installation A95234
NOTES:
ANGLE
IRON OR
EQUIVALENT
ROD LOCATION
USING DIMPLE
LOCATORS
(SEE DIMENSIONAL
DWG FOR
LOCATIONS)
3⁄8-IN. ROD
1. A 1 In. clearance minimum between top of
furnace and combustible material.
2. The entire length of furnace must be
supported when furnace is used in horizontal
position.
3/8-IN. HEX NUT
& WASHER (4)
REQD PER ROD
Fig. 6—Horizontal Application Using Blocks A95235
7

Use a backup wrench at the furnace gas control when
connecting the gas pipe to the furnace to avoid damaging gas
controls or manifold.
Never purge a line into a combustion chamber. Never use
matches, candles, flame, or other sources of ignition for the
purpose of checking leakage. Use a soap-and-water solution
to check for leakage. A failure to follow this warning can
cause a fire, explosion, personal injury, or death.
Step 9—Electrical Connections
115-V WIRING
Refer to the unit rating plate or Table 5 for equipment electrical
requirements. The control system requires an earth ground for
proper operation.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire.
Make all electrical connections in accordance with the National
Electrical Code (NEC) ANSI/NFPA 70-1993 and local codes or
Fig. 7—Side Filter Arrangement A95284
FILTER
RETAINER
WASHABLE
FILTER
Fig. 8—Bottom Filter Arrangement A93046
Table 3—Filter Information (In.)
FURNACE
CASING WIDTH FILTER SIZE* FILTER TYPE
Side Return Bottom Return
14-3/16‡ (1) 16 X 25 X 1† (1) 14 X 25 X 1 Cleanable
21 (1) 16 X 25 X 1 (1) 20 X 25 X 1† Cleanable
24-1/2 (2) 16 X 25 X 1† (1) 24 X 25 X 1 Cleanable
* Filters can be field modified by cutting the frame as marked and folding to the
desired size. Alternate sizes can be ordered from your distributor or dealer.
† Factory-provided with the furnace.
‡ External side filter rack must be used for upflow, right-side return.
Fig. 9—Leveling Leg Installation A89014
1 3⁄4″
1 3⁄4″
1 3⁄4″
1 3⁄4″
5⁄16″
5⁄16″
5⁄16″
5⁄16″
Table 4—Maximum Capacity of Pipe*
NOMINAL
IRON PIPE
SIZE (IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE (FT)
10 20 30 40 50
1/2 0.622 175 120 97 82 73
3/4 0.824 360 250 200 170 151
11.049 680 465 375 320 285
1-1/4 1.380 1400 950 770 660 580
1-1/2 1.610 2100 1460 1180 990 900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. wc) or less, and a
supply line pressure drop of 0.5-in. wc (based on a 0.60 specific gravity gas).
Ref: Table 10-2, NFGC.
Fig. 10—Typical Gas Pipe ArrangementA89417
8

ordinances that might apply. For Canadian installations, all elec-
trical connections must be made in accordance with CSA C22.1
Canadian Electrical Code, or authorities having jurisdiction.
The cabinet MUST have an uninterrupted or unbroken ground
according to NEC ANSI/NFPA 70-1993 and Canadian Elec-
trical Code, CSA C22.1 or local codes to minimize personal
injury if an electrical fault should occur. This may consist of
electrical wire or conduit approved for electrical ground when
installed in accordance with existing electrical codes. Do not
use gas piping as an electrical ground.
The junction box can be moved to the left-hand side of the furnace
when a left-hand side power supply is desired. Remove the 2
screws holding the junction box. Mount the junction box on the
left-hand side of the furnace. Holes have been provided in casing.
When moved, tuck the wiring harness behind the clip provided to
keep extra wire lengths out of the way.
NOTE: Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, the furnace control status LED will flash
rapidly and prevent heating operation.
24-V WIRING
Refer to ESD Precautions Procedure before proceeding with 24-v
connections.
Make field 24-v connections at the 24-v terminal block. (See Fig.
13.) Connect terminal Y/Y2 as shown in Fig. 11 or 12 for proper
cooling operation. Use only AWG No. 18 or larger, color-coded
copper thermostat wire.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the main control. Any 24-v electrical shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3-amp fuse. The control will
flash code 24 when the fuse needs replacement.
ACCESSORIES
1. Electronic air cleaner (EAC)
A terminal block (EAC-1 [hot] and EAC-2 [neutral]) is
provided for EAC connection. (See Fig. 13.) The terminals are
energized with 115v, 1-amp maximum during blower motor
operation.
2. Humidifier (HUM)
Screw terminals (HUM and Com) are provided for 24-v
humidifier connection. The terminals are energized with 24v,
0.5-amp maximum when the gas valve is energized.
Step 10— Venting
Refer to the enclosed Installation Instructions, GAMA Venting
Table for Category I Furnaces, and Venting Tables for 2- stage
Category I fan-assisted furnaces. In Canada use venting tables
found in CAN/CGA B149.1 or .2-M91 Amendment no. 1. The
horizontal portion of the venting system shall maintain a minimum
of 1/4-in. upward slope per linear ft (away from furnace), and it
shall be rigidly supported every 5 ft or less with hangers or straps
to ensure that there will be no movement after installation.
Step 11—Start-Up, Adjustment, and Safety Check
GENERAL
The furnace must have a 115-v power supply properly connected
and grounded. Correct polarity must be maintained to enable gas
heating operation.
The gas service pressure must not exceed 0.5 psig (14-in. wc), and
no less than 0.16 psig (4.5-in. wc).
This furnace can be installed with either a single-stage heating or
2-stage heating thermostat.
Thermostat wire connections at R and W/W1 are the minimum
required for gas heating operation. W2 must be connected for
2-stage heating thermostats. Y/Y2 and G are required to be
connected to furnace for cooling and heat pumps. G is required for
continuous fan. Com 24-v is required for some clock thermostats.
These connections must be made on the 24-v thermostat terminals
on the control. (See Fig. 13.) Y1 on 2-stage thermostat is required
for 2-stage cooling and 2-stage heat pump.
For single-stage thermostats, connect thermostat R to W/W1 at the
furnace control 24-v thermostat terminals. (See Fig. 11.) For
single-stage thermostats, the control will determine, based on
length of previous heating on and off cycles, when to operate in
low- and high-gas heat for optimum comfort. Setup switch-2
(SW-2) must be in the factory-shipped OFF position. See Fig. 14
and Tables 7 and 8 for setup switch information.
If a 2-stage heating thermostat is to be used, move SW-2 to the ON
position at the end of the furnace installation. This overrides the
built-in control process for selecting high and low fire and allows
the 2-stage thermostat to select gas heating modes. The W2 from
the thermostat must be connected to W2 on the control terminal
block. (See Fig. 12.)
This furnace is equipped with a manual reset limit switch in
the gas control area. The switch will open and shut off power
to the gas valve if a flame rollout or overheating condition
occurs in the gas control area. DO NOT bypass the switch.
Correct inadequate combustion-air supply, component fail-
ure, or restricted flue gas passageway before resetting the
switch.
Before operating the furnace, check each manual reset switch for
continuity. If necessary, press and release the button to reset the
switch.
SEQUENCE OF OPERATION
Using the schematic diagram in Fig. 15, follow the sequence of
operation through the different modes. Read and follow the
diagram very carefully.
Table 5—Electrical Data
UNIT SIZE VOLTS— HERTZ—
PHASE
OPERATING
VOLTAGE RANGE MAX
UNIT
AMPS
MIN
WIRE
GAGE
MAX WIRE
LENGTH (FT)‡
MAX FUSE OR
HACR-TYPE
CKT BKR AMPS†
Max* Min*
060-12 115—60—1 127 104 11.4 14 32 15
080-16 115—60—1 127 104 13.5 14 27 15
100-16 115—60—1 127 104 13.2 14 28 15
100-20 115—60—1 127 104 19.0 12 30 20
120-20 115—60—1 127 104 18.2 12 31 20
* Permissible limits of the voltage range at which the unit will operate satisfactorily.
† Time-delay fuse is recommended.
‡ Length shown is as measured 1 way along wire path between unit and service panel for maximum 2 percent voltage drop.
9

NOTE: If a power interruption occurs during a "call for heat"
(W/W1 or W/W1 and W2) and if the thermostat is still calling for
gas heating, the control will start a 90-sec blower only on period
2 sec after power is restored. The red LED will flash code 12
during the 90-sec period, after which the LED will be on
continuously as long as no faults are detected. After the 90-sec
period, the furnace will respond to the thermostat normally.
The blower door must be installed for power to be conducted
through the blower door interlock switch ILK to the furnace
control CPU, transformer TRAN, inducer motor IDM, blower
motor BLWM, hot surface ignitor HSI, and gas valve GV.
1. Adaptive Heating Mode—Single-Stage Thermostat with
2-Stage Heating
(See Fig. 11 for thermostat connections.)
NOTE: In response to thermostat call for heat R to W/W1, the
control selects high-stage gas heating only with HIGH HEAT
ONLY switch (SW1) set to ON regardless of the LOW HEAT
switch (SW2) setting. With the HIGH HEAT ONLY switch set to
OFF, LOW HEAT switch selects either low-stage gas heating only
mode when set to ON, or the adaptive heating mode when set to
OFF in response to a thermostat call for heat R to W/W1. (See Fig.
14 for description of switch settings or Fig. 16 for control circuit
diagram.)
This furnace can operate as a 2-stage furnace with a single-
stage thermostat because the furnace control CPU includes a
programmed adaptive sequence of controlled operation, which
Fig. 11—Heating and Cooling Application Wiring Diagram 1-Stage Thermostat and Condensing Unit
A95236
115-VOLT FIELD-
SUPPLIED
FUSED
DISCONNECT
JUNCTION
BOX CONTROL
BOX
24-VOLT
TERMINAL
BLOCK
THREE-WIRE
HEATING-
ONLY
FIVE
WIRE
NOTE 2
NOTE 1
1-STAGE
THERMOSTAT
TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
CONDENSING
UNIT
FURNACE
COM
R

WCY RG
GND
GND
FIELD 24-VOLT WIRING
FIELD 115-, 208/230-, 460-VOLT WIRING
FACTORY 24-VOLT WIRING
FACTORY 115-VOLT WIRING
Connect Y/Y2-terminal as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
208/230- OR
460-VOLT
THREE
PHASE
208/230-
VOLT
SINGLE
PHASE
WHT
BLK
WHT
BLK
W/W1
W2
Y/Y2
G
NOTES: 1.
2.
3.
Fig. 12—Heating and Cooling Application Wiring Diagram 2-Stage Thermostat and Condensing Unit
A95332
115-VOLT FIELD-
SUPPLIED
FUSED
DISCONNECT
JUNCTION
BOX CONTROL
BOX
24-VOLT
TERMINAL
BLOCK
FOUR-WIRE
HEATING-
ONLY
SEVEN
WIRE
2-STAGE
THERMOSTAT
TERMINALS FIELD-SUPPLIED
FUSED DISCONNECT
2-SPEED
CONDENSING
UNIT
FURNACE
G
R

W2 Y2 G Y1
GND
GND
FIELD 24-VOLT WIRING
FIELD 115-, 208/230-, 460-VOLT WIRING
FACTORY 24-VOLT WIRING
FACTORY 115-VOLT WIRING
208/230- OR
460-VOLT
THREE
PHASE
208/230-
VOLT
SINGLE
PHASE
 
Y2
Y1
C
WHT
BLK
WHT
BLK
W1CR
W2
COM
W/W1
Y/Y2
NOTE 2
NOTE 1
Connect Y/Y2-terminal as shown for proper operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
NOTES: 1.
2.
3.
10

selects low-gas-heat or high-gas-heat operation. This selection
is based upon the stored history of the length of previous gas
heating on/off periods of the single-stage thermostat.
The furnace will start up in either low- or high-gas heat. If the
furnace starts up in low-gas heat, the control CPU determines
the low-gas heat on time (from 0 to 16 minutes) which is
permitted before switching to high-gas heat.
If the power is interrupted, the stored history is erased. When
this happens, the control CPU selects low-gas heat for up to 16
minutes and then switches to high-gas heat, as long as the
thermostat continues to call for heat. Subsequent selection is
based on stored history of the thermostat cycle times.
When the wall thermostat "calls for heat", R-W/W1 circuit
closes. The furnace control performs a self-check, verifies the
low-heat and high-heat pressure switch contacts LPS and HPS
are open, and starts the inducer motor IDM in low speed or
high speed as appropriate.
a. Inducer prepurge period—As the inducer motor IDM
comes up to low speed or high speed, the low-heat pressure
switch contacts LPS (or LPS and HPS) close to begin a
15-sec prepurge period.
b. Ignitor warm-up—At the end of the prepurge period, the
hot surface ignitor HSI is energized for a 17-sec ignitor
warm-up period.
c. Trial-for-ignition sequence—When the ignitor warm-up
period is completed, the main gas valve relay contacts
MGVR-1 and -2 (and high-heat pressure switch relay
HPSR for high-stage operation) close to energize the low-
and high-heat gas valve solenoid(s) GV and the humidifier
terminal HUM. The gas valve opens, and 24-v power is
supplied for a field-installed humidifier at terminals HUM
and Com. The low-heat gas valve solenoid GV permits gas
flow to the burners where it is ignited. After 5 sec, the
ignitor HSI is de-energized, and a 2-sec flame-proving
period begins.
If the high-heat pressure switch HPS fails to close on call
for high-stage gas heat and the low-heat pressure switch
LPS closes, the furnace operates at low-heat gas flow rate
until the high-heat HPS pressure switch closes.
d. Flame-proving—When the burner flame is proved at the
flame-proving sensor electrode FSE, the control CPU
begins the blower on delay period and continues to hold the
gas valve GV open. If the burner flame is not proved within
2 sec, the control CPU closes the gas valve GV, and the
control CPU repeats the ignition sequence for up to 3 more
trials-for-ignition before going to ignition lockout. The
CONTROL TERMINATES LOCKOUT AUTOMATI-
CALLY after 3 hrs, or by momentarily interrupting 115-v
power to the furnace, or by interrupting 24-v power at
SEC1 or SEC2 to the control CPU (not at W/W1, G, R,
etc.). Opening the thermostat R-W circuit will not reset an
ignition lockout.
If flame is proved when flame should not be present, the
control CPU locks out of gas heating mode and operates
the inducer motor IDM on high speed until flame is no
longer proved.
e. Blower on delay—If the burner flame is proven, 45 sec
after the gas valve GV is opened the blower motor BLWM
is energized on the appropriate heating speed, low-gas-heat
or high-gas-heat speed. Simultaneously, the EAC terminals
EAC-1 and EAC-2 are energized with 115v and remain
energized as long as the blower motor BLWM is energized.
f. Switching from low- to high-gas heat—If the furnace
control CPU switches from low-gas heat to high-gas heat,
the control CPU switches the inducer motor IDM speed
from low to high. The high-heat pressure switch relay
HPSR closes. When the inducer motor IDM provides
sufficient pressure to close the high-heat pressure switch
HPS, the high-heat gas valve solenoid GV is energized. The
blower motor BLWM switches speed for high-gas heat 5
sec after the control CPU switches from low-gas heat to
high-gas heat.
g. Switching from high- to low-gas heat—The control CPU
will not switch from high-gas heat to low-gas heat while
the thermostat R to W circuit is closed when a single-stage
thermostat is used.
h. Blower off delay—When the thermostat is satisfied, the
R-W circuit is opened, de-energizing the gas valve GV,
stopping gas flow to the burners, the humidifier terminals
HUM and Com are de-energized. The inducer motor IDM
remains energized for a 5 sec post-purge period. The
blower motor BLWM and EAC terminals EAC-1 and
EAC-2 remain energized for 90, 135, 180, or 225 sec
(depending on selection at blower off delay switches SW-3
and SW-4). The furnace control CPU is factory set for a
135-sec blower off delay.
2. Non-Adaptive Heating Mode—Two-Stage Thermostat and
2-Stage Heating
(See Fig. 12 for thermostat connections).
Table 6—Setup Switch Description
SETUP
SWITCH NO. NORMAL POSITION DESCRIPTION OF USE
SW-1
High Heat Only OFF (Staged Gas Heat) Turn switch on to obtain only high-gas-heat operation on any call
for heat regardless of whether R-W/W1, or R-W/W1, -W2 is
closed. SW-1 overrides SW-2.
SW-2
Low Heat (Adaptive Algorithm) OFF (Single-Stage Thermostat)
Turn switch off for installations with single-stage thermostats; con-
trol selects low-gas-heat or high-gas-heat operation based on pre-
vious cycles. Turn switch on for installations with 2-stage thermo-
stats to permit only low-gas-heat operation in response to closing
R-W/W1. High-gas heat is supplied only when R to W/W1 and W2
are closed.
SW-3 and SW-4 ON, OFF Switches control gas heating mode blower off delay. (See Table
7.)
Table 7—Blower Off Delay Setup Switch (SW) Po-
sition
DESIRED HEATING
MODE BLOWER OFF
DELAY (SEC)
SETUP SWITCH
SW-3 SW-4
90 OFF OFF
135 OFF ON
180 ON OFF
225 ON ON
11

NOTE: In response to thermostat call for heat R to W/W1 and
with HIGH HEAT ONLY switch SW1 set to OFF, the control
selects low-stage heating only with LOW HEAT switch SW2 set
to ON, or the control selects adaptive heating mode with LOW
HEAT switch SW2 set to ON. The control selects high-stage
heating only with HIGH-HEAT ONLY switch SW1 set to ON. In
response to thermostat call for high-stage heat R to W1 and W2,
the control selects high-stage heating regardless of switch SW1
and SW2 settings. See Fig. 14 for description of switch settings or
Fig. 15 for control circuit diagram.
The start-up and shutdown functions and delays described in item
1. apply to the 2-stage heating mode as well, except for switching
from low- to high-stage and vice versa.
a. When the thermostat "calls for heat," the R-W/W1 circuit
closes for low-stage or the R to W1-and-W2 circuits close
for high-stage. The furnace control performs a self-check,
verifies the low-heat and high-heat pressure switch contacts
LPS and HPS are open, and starts the IDM in low speed or
high speed as appropriate.
b. Switching from low- to high-gas heat—If the thermostat
R-W/W1 circuit for low-stage is closed and the R-W2
circuit for high-gas heat closes, the control CPU switches
the IDM speed from low to high. The high-heat pressure
switch relay HPSR closes. When the inducer motor IDM
provides sufficient pressure to close the high-heat pressure
switch HPS, the high-heat gas valve solenoid GV is
energized. The blower motor BLWM switches speed to
high-gas heat 5 sec after the R-W2 circuit closes.
c. Switching from high- to low-gas heat—If the thermostat
R-W2 circuit for high-gas heat opens and the R-W/W1
circuit for low-gas heat remains closed, the control CPU
switches the inducer motor IDM speed from high to low.
The high-heat pressure switch relay HPSR opens to de-
energize the high-heat gas valve solenoid GV. When the
inducer motor IDM reduces pressure sufficiently, the
high-heat pressure switch HPS opens. The low-heat gas
valve solenoid GV remains energized as long as the
low-heat pressure switch LPS remains closed. The blower
motor BLWM switches to low-gas-heat 5 sec after the
R-W2 circuit opens.
3. Cooling Mode
a. Single-Speed Cooling Outdoor Unit
(See Fig. 11 for thermostat connections.)
(1.) The thermostat closes the R to G-and-Y circuits. The
R-Y/Y2 circuit starts the outdoor unit, and the R to
G-and-Y/Y2 circuits start the furnace blower motor
BLWM on high-cool speed.
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operat-
ing.
(3.) When the thermostat is satisfied, the R to G-and-
Y/Y2 circuits are opened. The outdoor unit stops, and
the furnace blower motor BLWM continues operating
on the high-cool speed for an additional 90 sec.
b. Two-Speed Cooling Outdoor Unit
(See Fig. 12 for thermostat connections.)
(1.) The thermostat closes the R to G-and-Y1 circuits for
low cooling or closes the R to G-and-Y1-and-Y/Y2
circuits for high cooling. The R to Y1 circuits start the
outdoor unit on low-cooling speed, and the R-G circuit
starts the furnace blower motor BLWM on low-
cooling speed (same speed as for low-gas heat). The R
to Y1-and-Y2 circuits start the outdoor unit on high-
cooling speed, and the R to G-and-Y2 circuits start
the furnace blower motor BLWM on high-cooling
speed.
NOTE: Y1 is found in the outdoor unit. The furnace control CPU
controls blower motor BLWM speed by sensing only G for
low-cooling speed and Y/Y2 for high-cooling speed.
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operating
on either cooling speed.
(3.) When the thermostat is satisfied, the R to G-and-Y1
or R to G-and-Y1-and-Y/Y2 circuits open. The out-
door unit stops, and the furnace blower continues
operating on the cooling speed for an additional 90
sec.
4. Continuous Blower Mode
a. When the R to G circuit is closed by the thermostat, the
blower motor BLWM operates on low-gas heat speed
(identical to low-cool speed). Terminals EAC-1 and EAC-2
are energized with 115v as long as the blower motor
BLWM is energized.
b. During a "call for heat," the blower motor BLWM stops
during ignitor warm-up (17 sec), ignition (7 sec), and
blower on delay (45 sec), allowing the furnace heat
exchangers to heat up quickly.
c. The blower motor BLWM reverts to continuous blower
speed after the heating cycle is completed. In high-gas heat,
the furnace control CPU holds the blower motor BLWM at
high-gas-heat speed during the selected blower off delay
period before reverting to continuous blower speed.
(1.) When the thermostat "calls for low-cooling," the
blower motor BLWM continues to operate on low-
cool speed. When the thermostat is satisfied, the
blower motor BLWM continues on continuous blower
speed.
(2.) When the thermostat "calls for high-cooling," the
blower motor BLWM operates on high-cool speed.
When the thermostat is satisfied, the blower motor
BLWM operates an additional 2 sec on high-cool
speed before reverting back to continuous blower
speed.
(3.) When the R-G circuit is opened, the blower motor
BLWM continues operating for an additional 90 sec if
no other function requires blower motor BLWM
operation.
5. Heat Pump Mode
NOTE: A dual fuel thermostat or accessory interface kit is
required with single-speed heat pumps. See dual fuel thermostat or
interface kit Installation Instructions for single-speed heat pump
thermostat and interface connections. No interface kit is needed for
2-speed heat pumps. See 2-speed heat pump Installation Instruc-
tions to determine whether a standard or dual-fuel heat pump
thermostat is required and for thermostat connections.
a. Single-Speed Heat Pump Cooling
(1.) The thermostat and interface kit close the R to
G-and-Y/Y2 circuit to start the furnace blower motor
BLWM on high-cooling speed. The Y/Y2 input to the
furnace control is necessary to provide adequate cool-
ing airflow.
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operat-
ing.
12

(3.) When the thermostat is satisfied, furnace blower motor
BLWM continues operating on the high-cool speed for
an additional 90 sec.
b. Two-Speed Heat Pump Cooling
(1.) The thermostat R to G circuits start the furnace blower
motor BLWM on low-cool speed. The thermostat
R to G-and-Y/Y2 circuits start the furnace blower
motor BLWM on high-cool speed.
NOTE: The furnace control CPU controls blower motor BLWM
speed by sensing only G for low-cool speed and Y2 for high-cool
speed.
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operating
on either cooling speed.
(3.) When the thermostat is satisfied, the furnace blower
motor BLWM continues operating on the cooling
speed for an additional 90 sec.
c. Single-Speed Heat Pump Heating
(1.) The thermostat and accessory interface kit R to G-
and-Y/Y2 circuits start the furnace blower motor
BLWM on heat pump high-heat speed (identical to
high-cool speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operat-
ing.
(3.) When the thermostat is satisfied, the furnace blower
motor BLWM continues operating on the heat pump
high-heat speed for an additional 90 sec.
d. Two-Speed Heat Pump Heating
(1.) The thermostat closes the R-G circuit for low heat and
starts the furnace blower motor BLWM on heat pump
low-heat speed (identical to low-cooling speed). Clos-
ing the R-Y/Y2 circuit to the furnace provides blower
motor BLWM heat pump high-heat speed.
NOTE: The furnace control CPU controls blower motor BLWM
speed by sensing only G (for heat pump low-heat speed) and Y2
(for heat pump high-heat speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operating
on either heating speed.
(3.) When the thermostat is satisfied, the furnace blower
motor BLWM continues operating on the heating
speed for an additional 90 sec.
(4.) Opening only the R-Y/Y2 circuit reduces the blower
motor BLWM speed to heat pump low-heat speed.
6. Defrost
a. When the furnace control R to W/W1-and-Y/Y2 circuits
are closed, the furnace control CPU continues blower
motor BLWM operation at the heat pump heating speed
until the end of the prepurge period, then shuts off until the
end of the HSI ignitor-on period (22 sec).
b. When installed with a heat pump, the furnace control CPU
automatically holds the blower off time to 22 sec during the
HSI ignitor on period. After 17 sec of the HSI ignitor-on
period, a trial-for-ignition sequence occurs as described
above for gas heating. After flame is proved and without a
blower on delay, the blower motor BLWM then operates
on high-gas-heat speed during defrost. For both single-
speed and 2-speed heat pumps, defrost mode is in high-gas
heat only.
c. When furnace control R-W/W1 circuit is opened, the
furnace control CPU begins the normal inducer post purge
period and the blower motor BLWM remains on for the
blower off delay period. If the R-G circuit remains closed,
the blower motor BLWM reverts to continuous operation.
START-UP PROCEDURES
1. Component test—The furnace features a component test
system to help diagnose a system problem in the case of a
component failure. To initiate the component test procedure,
ensure that there are no thermostat inputs to the control and all
time delays have expired. Short the TWIN/TEST terminal to
ground or Com for 1 to 4 sec. (See Fig. 13.)
NOTE: The component test feature will not operate if the control
is receiving any thermostat signals or until all time delays have
expired.
Fig. 13—Control Center A95231
123
456
78 9
PR2
L2
COM
PR1
L1
EAC-2
EAC-1
HI-COOL
HI-GAS
-HEAT
LO-GAS
-HEAT
PARK
3
FU1
SEC-1 SEC-2
1
123
456
789
10 11 12
MASTER SLAVE
TWIN
TEST
LED
GRY/Y2W/W1
COM
24 V
W2
1
ON
OFF
FURNACE AND
BLOWER OFF DELAY
SETUP SWITCHES
24-VOLT
THERMOSTAT
TERMINALS
EAC - ELECTRONIC
AIR CLEANER
(115-VAC 1 AMP MAX) 3-AMP
FUSE
LED -
DIAGNOSTIC
LIGHT
TWIN / TEST
TERMINAL
HUM -
HUMIDIFIER
(24-VAC 0.5
AMP MAX)
HUM
Fig. 14—Setup Switches on Control Center
(Factory Settings)
A93377
BLOWER-
OFF
DELAY
LOW
HEAT
(ADAPTIVE
ALGORITHM)
HIGH
HEAT
ONLY
ON OFF
4
3
2
1
13

The component test sequence is as follows:
a. The furnace control checks itself, operates the inducer
motor on low speed for 7 sec and on high speed for 7 sec,
then stops.
b. The hot surface ignitor is energized for 15 sec, then
de-energized.
c. The blower motor operates on low-gas-heat/heat pump
low-heat/low-cool/continuous fan speed for 7 sec, then
stops.
d. The blower motor operates on high-gas heat for 7 sec, then
stops. The gas valve and humidifier terminal HUM are not
energized for safety reasons.
e. The blower motor operates on heat pump high-heat/high-
cool speed for 7 sec, then stops.
NOTE: The EAC terminals are energized when the blower is
energized.
2. After all connections have been made, purge gas lines and
check for leaks.
Never purge a line into a combustion chamber. Never use
matches, candles, flame, or other sources of ignition for the
purpose of checking leakage. Use a soap-and-water solution
to check for leakage. A failure to follow this warning can
cause a fire, explosion, personal injury, or death.
3. To operate furnace, follow procedures on operating instruc-
tions label attached to furnace.
4. With furnace operating, set thermostat below room tempera-
ture and observe that furnace goes off. Set thermostat above
room temperature and observe that furnace restarts.
ADJUSTMENTS
1. Set gas input rate.
The gas input rate must be set for both high fire and low fire.
Each adjustment is made independently at the gas control
regulators.
There are 2 methods of adjusting the gas input rate. The
preferred method is by using Table 8 and following instruc-
tions in item a. The second method is by clocking the gas
meter and following instructions in item b.
The procedure in item b. MUST be used for altitudes above
2000 ft.
The gas valve regulator has been nominally set at 1.5-in. wc
for low fire and 3.5-in. wc for high fire for natural gas.
a. Check gas input rate using Table 8.
(1.) Obtain average yearly heat value for local gas supply.
(2.) Obtain average yearly specific gravity for local gas
supply.
(3.) Verify furnace model. Table 8 can only be used for
model 58UXT Furnaces.
(4.) Check and verify orifice size in furnace. NEVER
ASSUME THE ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
(5.) Find natural gas heat value and specific gravity in
Table 8.
(6.) Follow heat value and specific gravity lines to point of
intersection. Find orifice size and manifold pressure
settings for proper operation at given natural gas
conditions on low and high fire.
EXAMPLE:
Heat value = 980 Btu/cu ft
Specific gravity = 0.62
Therefore: Orifice No. 44*
Manifold pressure 3.5-in. wc on high fire and 1.5-in. wc on
low fire.
* The furnace is shipped with No. 45 orifices. Therefore, in
this example all main burner orifices must be changed and
manifold pressure must be adjusted.
(7.) Proceed to item c. to adjust manifold pressure.
b. Check gas input rate by clocking gas meter for low and
high fire.
(1.) Obtain average yearly heat value for local gas supply.
NOTE: Be sure heating value used for calculations is correct for
your altitude. Consult local gas utility for altitude adjustments (if
any) of gas heating value.
(2.) Check and verify orifice size in furnace. NEVER
ASSUME THE ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
(3.) Turn off all other gas appliances and pilots.
(4.) Turn SW-2 to ON. Close R-W/W1 and jumper R to
W2 to start furnace in high fire and let run for 3
minutes.
(5.) Measure time (in sec) for gas meter to complete 1
revolution.
(6.) Refer to Table 8 for cubic ft of gas per hr.
(7.) Multiply gas rate (cubic ft/hr) by heating value (Btu/
cubic ft).
EXAMPLE: Btu/hr heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 1070 Btu/cu ft
Time for 1 revolution of 2-cu ft dial = 72 sec
Gas rate = 100 cu ft/hr (from Table 9)
Btu heating input = 100 X 1070 = 107,000 Btuh
(8.) Remove jumper R to W2 and repeat items (5.) through
(8.) for low fire.
NOTE: High altitude—In the United States, gas input on rating
plate is for altitudes up to 2000 ft. for natural and propane gases.
Ratings for altitudes over 2000 ft MUST be reduced 4 percent for
each 1000 ft above sea level. To obtain the adjusted altitude rating,
adjust the manifold pressure (see item c.) and replace the main
burner orifices as needed. Refer to NFGC Appendix F, Table F-4
for proper orifice sizing at high altitudes. Installations at altitudes
5500 feet or higher above sea level shall use a factory supplied
high-altitude conversion kit.
NOTE: Canadian installations only—The Canadian ratings are
approved for altitudes up to 2000 ft for natural and propane gases.
High-altitude ratings are from 2000 ft to 4500 ft above sea level.
High-altitude rating includes a 10 percent derate as required by
Canadian standards.
(9.) Measured gas inputs should equal low- and high-fire
gas inputs on unit rating plate ±2 percent.
(10.) Proceed to item c. to adjust manifold pressure.
14

Fig. 15—Unit Wiring Diagram A95239
LEGEND
ALS1 AUXILIARY LIMIT SWITCH, OVERTEMP. MANUAL RESET, SPST (N.C.) ALS2 AUXILIARY LIMIT SWITCH, OVERTEMP. AUTO RESET, SPST (N.C.) BHI / LOR BLOWER MOTOR SPEED CHANGE RELAY, SPDT BHT / CLR BLOWER MOTOR SPEED CHANGE RELAY, SPDT BLWM BLOWER MOTOR, 4-SPEED, PERMANENT-SPLIT-CAPACITOR BLWR BLOWER MOTOR RELAY, SPST (N.O.) CAP CAPACITOR CPU MICROPROCESSOR AND CIRCUITRY DSS DRAFT SAFEGUARD SWITCH (N.C.) EAC-1 ELECTRONIC AIR CLEANER CONNECTION (115 VAC, 1 AMP MAX.) EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON) FRS1 FLAME ROLLOUT SWITCH OVERTEMP. MANUAL RESET, SPST (N.C.) FRS2 FLAME ROLLOUT SWITCH OVERTEMP. MANUAL RESET, SPST (N.C.) FSE FLAME-PROVING SENSOR ELECTRODE FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED FU2 FUSE, FIELD INSTALLED GV GAS VALVE, REDUNDANT LOW-HEAT OPERATORS, 2-STAGE HPS HIGH-HEAT PRESSURE SWITCH, SPST (N.O.) HPSR HIGH-HEAT PRESSURE SWITCH RELAY, SPST (N.C.) HSI HOT-SURFACE IGNITER (115 VAC) HSIR HOT-SURFACE IGNITOR RELAY, SPST (N.O.) HUM 24VAC HUMIDIFIER CONNECTION (0.5 AMP. MAX.) IDM INDUCED DRAFT MOTOR, 2-SPEED, SHADED-POLE IDR INDUCER MOTOR RELAY, SPST (N.O.) IHI / LOR INDUCER MOTOR SPEED CHANGE RELAY, SPDT ILK BLOWER DOOR INTERLOCK SWITCH, SPST (N.O.) JB JUNCTION BOX LED LIGHT-EMITTING DIODE FOR STATUS CODES LGPS LOW GAS-PRESSURE SWITCH, SPST (N.O.) LPS LOW-HEAT PRESSURE SWITCH, SPST (N.O.) LS LIMIT SWITCH, OVERTEMPERATURE-AUTO RESET, SPST (N.C.)
MGVR MAIN GAS VALVE RELAY, DPST (N.O.)
-
1 = VALVE
-
2 = HUMIDIFIER
PL1 12-CIRCUIT CONNECTOR PL2 9-CIRCUIT CONNECTOR PL3 3-CIRCUIT IDM CONNECTOR PL6 2-CIRCUIT HSI CONNECTOR SW1 HIGH-HEAT-ONLY SWITCH, SPST (MANUAL)
*
SW2 LOW-HAT-ONLY SWITCH, SPST (MANUAL)
*
SW3 & 4 BLOWER-OFF DELAY SETTING SWITCHES,
SPST (MANUAL)
*
TJ TWINNING JUMPER, SPDT FOR MASTER OR
SLAVE STATUS (MANUAL CHANGE OVER)
TRAN TRANSFORMER-115VAC/24VAC TWIN/TEST 1-CIRCUIT TWINNING BUSS CONNECTOR,
ALSO STATUS CODE RECALL
JUNCTION TERMINAL CONTROL TERMINAL FACTORY POWER WIRING (115VAC) FACTORY CONTROL WIRING (24VAC) FIELD POWER WIRING (115VAC) FIELD CONTROL WIRING (24VAC) CONDUCTOR ON CONTROL FIELD WIRING SCREW TERMINAL FIELD GROUND EQUIPMENT GROUND FIELD SPLICE PLUG RECEPTACLE
NOTES:
322292-101 REV. A
1. Use only copper wire between the disconnect switch and the unit. 2. If any of the original wire, as supplied, must be replaced, use the
same or equivalent type wire.
3. Inducer (IDM) and blower (BLWM) motors contain internal auto-reset
thermal overload switches.
4. Blower motor speed selections are for average conditions. See
Installation Instructions for details on optimum speed selection.
5. Replace only with a 3-AMP fuse. 6. Auxiliary limit switches (ALS1 & 2) used on some horizontal and
some downflow models.
7. This wire must be connected to furnace sheet metal for
control to prove flame.
RED
LS FRS2
RED
RED
FRS1
(WHEN USED) ALS1
DSS
ORN
LGPS
YEL
NOTE #8
LPS
NOTE #8
(WHEN USED)
RED
YEL
ORN
(WHEN USED)
NOTE #6
ALS2
ORN
SWITCH
12
HEAT SET-UP SWITCH NORM HI HT LO HT
*
ON
OFF
OFF
ON
BLOWER- OFF DELAY (SEC.) SWITCH
34
90 SEC
135 SEC
*
180 SEC 225 SEC
ON
OFF
OFF
ON
2-STAGE
FURNACE
CONTROL
FACTORY
SETTINGS
1234
ON
OFF
321
BLU
BLOWER-OFF DELAY BLOWER-OFF DELAY LOW-HEAT ONLY HIGH-HEAT ONLY
*
REDRED
ORN
W2 Com
24V W/W1 Y/Y2 R G HUM LED S
M
TJ
TWIN
TEST
12 11 10
GRN GRY
BRN
P1
WHT
BLK
GRY
YEL
321
987
WHT FSE
BLK
GRY
BRN
HPS BRN HI
P
BLU
GRN
M
IDM
HSI GRN ILK JB
L1
WHTPL6
RED
BLK
WHT
BLK
WHT
12
123
PL3
WHT
BLK
RED
PL2
PR1 PR2
L1 L2
COMMON
HI-COOL
HI-GAS
HEAT EAC-2
EAC-1
LO-GAS
HEAT PARK
SEC1
FU1SEC2 RED
BLU
NOTE #4
COM
HI
MED HI MED LO LO RED
BLU
YEL
BLK
WHT
BLWM
BRN BRN
CAP
WHT
BLK
TRAN
RED
BLU
WHT
BLK
GV CGRN
FUSED DISCONNECT
SWITCH (WHEN REQ’D)
NOTE #1
BLK
WHT
GRN
L2
GRN
FU2
CONNECTION DIAGRAM
L1 BLWR
TO 115VAC FIELD DISCONNECT SWITCH
NOTE #1
EQUIPMENT GROUND
LO-GAS-HEAT
HI-GAS-HEAT
PARK
NOTE #4
COMMON
HSIR EAC-1
COM
HI
MED HI
MED LO
LO
SCHEMATIC DIAGRAM (NATURAL GAS & PROPANE)
EAC-2
31HSI
2
9
PL2
PR2
115VAC
PR1
TRAN
24VAC
IDR
L2
ILK
IDM
BLWM
BHI / LOR
BHT / CLR
CAP
BRN
BRN
PL6
IHI / LOR
SEC1
FU1
NOTE #5
1
2
3
HI
COM
HPSR 1
5
6
2
N/A N/A
HI-COOL
PL3
4 7
SEC2
8
LS
ALS1
DSS
ALS2
FRS1
(WHEN USED)
FRS2
N/A
12
2
3
MGVR-2
9 6
NOTE #8 LPS
(WHEN USED)
TWIN TEST SLAVE
MASTER
W/W1
R
HUM
TWINNING
JUMPER
TJ
W2
Y/Y2
G
MGVR-1
NOTE #8
HPS
5
4
1
10
7
8N/A
N/A
FSE
11
HI
MP
C
NOTE#7
PL1
COMPONENT TEST
To initiate the component test sequence with no thermostat inputs and with all inducer Post-Purge and Blower-Off Delay periods completed, short the "TWIN/TEST" terminal to the "
C
OM" terminal for about two seconds. The control will
turn ON the inducer motor Low-Speed, inducer motor High-Speed, HSI, blower motor Low-Gas-Heat Speed, blower motor High-Gas-Heat Speed, and blower motor High-Cool Speed for 7-15 seconds each. Neither the gas valve nor the humidifier will be turned ON.
CPU
LGPS
LO
SW1
GV
ORN
SW4
SW3
SW2
C
OM
8. Factory connected when LGPS not used. 9. Symbols are an electrical representation only. 10. BLOWER-ON DELAY: Gas heating 45 seconds,
Cooling/Heat Pump 2 seconds.
11. Cooling/Heat Pump BLOWER-OFF DELAY is 90
seconds.
12. IGNITION-LOCKOUT will occur after four consecutive
unsuccessful trials-for-ignition. Control will automatically reset after three hours.
13. Control must be grounded at pin 10 of 12-pin connector. 14. NA - Not Applicable
15

DO NOT redrill burner orifices. Improper drilling (burrs, out-
of- round, etc.) can cause excessive burner operating noise
and misdirection of burner flames. This could result in flame
impingement on burners and heat exchanger surfaces, leading
to potential failures.
c. Adjust gas manifold pressure
(1.) Move SW-2 to the ON position to lock out the
adaptive algorithm. (See Fig. 13 and 14.) Jumper R to
W/W1 and W2 to call for high-gas heat.
(2.) Remove gas control regulator adjustment seal caps.
(See Fig. 16.)
(3.) Turn high-stage adjusting screw (5/64-in. hex Allen
wrench) counterclockwise (out) to decrease input rate
or clockwise (in) to increase rate. When adjusting
input rate, DO NOT set manifold pressure less than
3.2-in. wc or more than 3.8-in. wc for natural gas. If
manifold pressure is outside this range, change main
burner orifices.
(4.) Remove R-to-W2 jumper to place furnace in low-stage
operation for low-stage adjustment.
(5.) Turn low-stage adjusting screw (5/64-in. hex Allen
wrench) counterclockwise (out) to decrease input rate
or clockwise (in) to increase rate. When adjusting
input rate, DO NOT set manifold pressure less than
1.3-in wc or more than 1.7-in. wc for natural gas. If
manifold pressure is outside this range, change main
burner orifices.
NOTE: If orifices are changed, both high-stage and low-stage
input rates must be readjusted, with manifold pressures within
ranges specified in items (3.) and (5.).
NOTE: If orifice hole appears damaged or it is suspected to have
been redrilled, check the orifice size with a numbered drill bit of
the correct size. Never use a redrilled orifice. A burr-free and
squarely aligned orifice hole is essential for proper flame charac-
teristics.
(6.) Remove jumper on R-W/W1 after low-stage adjust-
ments.
(7.) When correct input is obtained, replace regulator seal
caps. Main burner flame should be clear blue, almost
transparent. (See Fig. 17.)
2. Set temperature rise.
Place SW-2 in ON position. Jumper R to W/W1 and W2 to
check high-gas-heat temperature rise. To check low-gas-heat
temperature rise, remove jumper to W2. Determine air tem-
perature rise for both high- and low-stages. Do not exceed the
temperature rise ranges specified on the unit rating plate for
high and low stage.
Table 8—Model 58UXT Orifice Size and Manifold Pressure for Correct Input Rate
(Tabulated Data Based on Altitude Up to 2000 ft and 20,000 Btuh High Heat/13,000 Btuh Low Heat Per Burner)*
GAS HEAT
VALUE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.60 0.62 0.64 0.66 0.68 0.70 0.72
Orf
No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low Orf No. Heat High/Low
860 43 3.7/1.6 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.5 41
42 3.2/1.4 3.6/1.5 41 42 3.3/1.4 3.7/1.5 41 42 3.4/1.4 3.8/1.6
875 43 3.6/1.5 43 3.7/1.6 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.4 41
42 3.2/1.3 3.5/1.5 41 42 3.3/1.4 3.6/1.5
890 43 3.5/1.5 43 3.6/1.5 43 3.7/1.6 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.4 41
42 3.2/1.3 3.5/1.5
905 43
44 3.3/1.3 3.7/1.5 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5 43 3.8/1.6 42 3.2/1.4 42 3.3/1.4 42 3.4/1.4
920 43
44 3.2/1.3 3.7/1.5 43 44 3.3/1.4 3.8/1.6 43 3.5/1.4 43 3.6/1.5 43 3.7/1.5 43 3.8/1.5 42 3.2/1.3 42 3.3/1.3
935 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6 43 3.5/1.5 43 3.6/1.5 43 3.7/1.5 43 3.8/1.6 42 3.2/1.3
950 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6 43 3.4/1.5 43 3.6/1.5 43 3.7/1.5 43 3.8/1.6
965 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6 43 3.4/1.5 43 3.5/1.5 43 3.6/1.5
980 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6 43 3.4/1.5 43 3.5/1.5
995 44
45 3.2/1.3 3.8/1.6 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6 43 3.4/1.4
1010 45 3.7/1.6 44
45 3.2/1.3 3.8/1.6 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6 43 44 3.3/1.4 3.8/1.6
1025 45
46 3.6/1.5 3.8/1.6 45 3.7/1.6 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5 43
44 3.2/1.4 3.7/1.6
1040 45
46 3.5/1.5 3.7/1.6 45 46 3.6/1.5 3.8/1.6 45 3.7/1.6 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5 44 3.6/1.5
1055 45
46 3.4/1.4 3.6/1.5 45 46 3.5/1.5 3.7/1.6 45 46 3.6/1.5 3.8/1.6 45 3.8/1.6 44 3.2/1.3 44 3.3/1.4 44 3.4/1.4 44 3.5/1.5
1070 45
46 3.3/1.4 3.5/1.5 45 46 3.4/1.4 3.6/1.5 45 46 3.5/1.5 3.7/1.6 45 46 3.7/1.5 3.8/1.6 45 3.8/1.6 44 3.2/1.4 44 3.3/1.4 44 3.4/1.4
1085 45 46
47
3.2/1.4
3.4/1.4
3.8/1.6 45
46 3.3/1.4 3.5/1.5 45 46 3.4/1.5 3.6/1.5 45 46 3.6/1.5 3.7/1.6 45 3.7/1.5 45 3.8/1.6 44 3.2/1.4 44 3.3/1.4
1100 46
47 3.3/1.4 3.7/1.6 45 46 3.2/1.4 3.4/1.4 45 46 3.4/1.4 3.5/1.5 45 46 3.5/1.5 3.6/1.5 45 46 3.6/1.5 3.8/1.6 45 3.7/1.6 45 3.8/1.6 44 3.2/1.4
16

a. Place duct thermometers in return and supply ducts as near
furnace as possible. Be sure thermometers do not see heat
exchangers so that radiant heat will not affect thermometer
readings. This is particularly important with straight run
ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine tem-
perature rise.
NOTE: If the temperature rise is outside this range, first check:
(1.) Gas input for low- and high-stage operation.
(2.) Derate for altitude if applicable.
(3.) Return and supply ducts for excessive restrictions
causing static pressures greater than 0.50-in. wc.
c. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise. For high stage,
speed selection can be med-high or med-low (factory
setting). For low stage, speed selection can be low (factory
setting) or med-low if high-stage speed selection is med-
high.
Disconnect the electrical power before changing the speed
tap. A failure to follow this warning can cause personal injury
or death.
d. To change motor speed selection for high heat, remove
blower motor lead from control HIGH-GAS-HEAT termi-
nal. (See Fig. 13. and 15.) Select desired blower motor
speed lead from 1 of the other terminals and relocate it to
the HIGH-GAS-HEAT terminal. (See Table 10 for lead
color identification.) Reconnect original lead to the PARK
terminal. Follow this procedure for proper selection of cool
and low-gas-heat speed selection.
Recheck the temperature rise. It must be within the limits
specified on the unit rating plate. Recommended operation is
at midpoint of rise range or above.
3. Set thermostat heat anticipator.
a. When using a nonelectronic thermostat, the thermostat heat
anticipation must be set to match the amp draw of the
Table 9—Gas Rate (Cu Ft/Hr)
SECONDS
FOR 1
REVOLUTION
SIZE OF TEST DIAL SECONDS
FOR 1
REVOLUTION
SIZE OF TEST DIAL
1
cu ft 2 cu ft 5 cu ft 1 cu ft 2 cu ft 5 cu ft
10
11
12
13
14
360
327
300
277
257
720
655
600
555
514
1800
1636
1500
1385
1286
50
51
52
53
54
72
71
69
68
67
144
141
138
136
133
360
355
346
340
333
15
16
17
18
19
240
225
212
200
189
480
450
424
400
379
1200
1125
1059
100
947
55
56
57
58
59
65
64
63
62
61
131
129
126
124
122
327
321
316
310
305
20
21
22
23
24
180
171
164
157
150
360
343
327
313
300
900
857
818
783
750
60
62
64
66
68
60
58
56
54
53
120
116
112
109
106
300
290
281
273
265
25
26
27
28
29
144
138
133
129
124
288
277
267
257
248
720
692
667
643
621
70
72
74
76
78
51
50
48
47
46
103
100
97
95
92
257
250
243
237
231
30
31
32
33
34
120
116
113
109
106
240
232
225
218
212
600
581
563
545
529
80
82
84
86
88
45
44
43
42
41
90
88
86
84
82
225
220
214
209
205
35
36
37
38
39
103
100
97
95
92
206
200
195
189
185
514
500
486
474
462
90
92
94
96
98
40
39
38
38
37
80
78
76
75
74
200
196
192
188
184
40
41
42
43
44
90
88
86
84
82
180
176
172
167
164
450
439
429
419
409
100
102
104
106
108
36
35
35
34
33
72
71
69
68
67
180
178
173
170
167
45
46
47
48
49
80
78
76
75
73
160
157
153
150
147
400
391
383
375
367
110
112
116
120
33
32
31
30
65
64
62
60
164
161
155
150
Fig. 16—Redundant Automatic Gas Control Valve
A93376
LOW-STAGE
ADJUSTMENT
ALLEN SCREW
(UNDER CAP)
HIGH-STAGE
ADJUSTMENT
ALLEN SCREW
(UNDER CAP)
MANUAL
ON/OFF
INLET
PRESSURE
TAP
MANIFOLD
PRESSURE
TAP
Fig. 17—Burner Flame A89020


BURNER FLAME
BURNER
MANIFOLD
Table 10—Speed Selection
COLOR SPEED AS SHIPPED
White Common Com
Black High Cool
Yellow Med-High Park
Blue Med-Low High-Gas Heat
Red Low* Low-Gas Heat
* Continuous blower speed
17

electrical components in the R-W/W1 circuit. Accurate
amp draw readings can be obtained at the wires normally
connected to thermostat subbase terminals R and W/W1.
Fig. 18 illustrates an easy method of obtaining the actual
amp draw. The amp reading should be taken after the
blower motor has started and the furnace is operating in
low stage. To operate the furnace in low stage, first move
SW-2 to ON position, THEN connect the ammeter wires as
shown in Fig. 18. The thermostat anticipator should NOT
be in this circuit while measuring the current. If the
thermostat has no subbase, the thermostat MUST be
disconnected from the R and W/W1 wires during the
current measurement. Return SW-2 to final desired location
after completing the reading. See the thermostat manufac-
turer’s instructions for adjusting the heat anticipator and for
varying the heating cycle length.
b. When using an electronic thermostat, set the cycle rate for
3 cycles per hr.
CHECK SAFETY CONTROLS
The flame sensor, gas valve, and pressure switches were all
checked in the Start-up section as part of normal operation.
1. Check primary limit control.
This control shuts off the combustion control system and
energizes the circulating-air blower motor if the furnace
overheats.
The preferred method of checking the limit control is to
gradually block off the return air after the furnace has been
operating for a period of at least 5 minutes. As soon as the
limit has shut off the burners, the return-air opening should be
unblocked. By using this method to check the limit control, it
can be established that the limit is functioning properly and
will operate if there is a motor failure.
2. Check draft safeguard switch.
The purpose of this control is to cause safe shutdown of the
furnace during certain blocked vent conditions.
a. Disconnect power to furnace and remove vent connector
from furnace flue collar. Be sure to allow time for vent
connector pipe to cool down before removing.
b. Restore power to furnace and set room thermostat above
room temperature.
c. After normal start-up, allow furnace to operate for 2
minutes, then block flue outlet 100 percent. Furnace should
cycle off within 2 minutes.
d. Remove blockage and reconnect vent connector to furnace
flue collar.
e. Wait 5 minutes and then reset draft safeguard switch.
3. Check flow-sensing pressure switches.
This control proves operation of draft inducer blower.
a. Turn off 115-v power to furnace.
b. Remove gas control door and disconnect inducer motor
lead wires from wire harness.
c. Turn on 115-v power to furnace.
d. Close thermostat switch as if making normal furnace start.
If the hot surface ignitor does not glow within several
minutes and control flashes code 32, then the flow-sensing
switches are functioning properly.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace gas control door,
and turn on 115-v power.
CHECKLIST
1. Put away tools and instruments, and clean up debris.
2. Check SW-1 through SW-4 after completing installation to
ensure desired settings for thermostat type (SW-1 and SW-2)
and blower off delay (SW-3 and SW-4). Refer to Tables 7 and
8.
3. Verify manual reset switches have continuity.
4. Ensure blower and gas control access doors are properly
installed.
5. Cycle test furnace with room thermostat.
6. Check operation of accessories per manufacturer’s instruc-
tions.
7. Review User’s Manual with owner.
8. Leave literature packet near furnace.
Fig. 18—Amp Draw Check With Ammeter
A80201
R Y W G
10 TURNS
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
HOOK-AROUND
VOLT/AMMETER
EXAMPLE: 5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS = 0.5 AMPS FOR THERMOSTAT SETTING
FROM UNIT 24-VOLT
TERMINAL BLOCK
Copyright 1995 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 58uxt1si
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab 6a 8a PC 101 Catalog No. 535-847 Printed in U.S.A. Form 58UXT-1SI Pg 18 7-95 Replaces: New