58DFA
Downflow Induced-Combustion Furnaces
Installation, Start-Up, and Operating Instructions
→
Sizes 071-135 Series 120
NOTE: Read the entire instruction manual before starting the
installation.
Index
Page
SAFETY CONSIDERATIONS .....................................................1
Clearance From Combustible Materials...................................1
INTRODUCTION.......................................................................1-2
Dimensional Drawing ...............................................................2
LOCATION....................................................................................3
General ......................................................................................3
Location Relative To Cooling Equipment ...............................3
Hazardous Locations.................................................................3
AIR FOR COMBUSTION AND VENTILATION...................3-5
Unconfined Space..................................................................3-4
Confined Space......................................................................4-5
SUPPLY-AIR PLENUM INSTALLATION..............................5-6
Concrete Slab ............................................................................5
Combustible Floor ..................................................................5
FILTER ARRANGEMENT...........................................................6
GAS PIPING ..................................................................................6
ELECTRICAL CONNECTIONS...............................................6-7
115-v Wiring..........................................................................6-7
24-v Wiring .............................................................................7
Accessory ..................................................................................7
VENTING ......................................................................................7
START-UP, ADJUSTMENT, AND SAFETY CHECK ..............7
General ......................................................................................7
Sequence Of Operation .......................................................7-10
Heating Mode............................................................................8
Cooling Mode ......................................................................8-10
Continuous Blower Mode.......................................................10
Start-Up Procedures ................................................................10
Adjustments .......................................................................10-12
Check Safety Controls.......................................................12-13
Checklist ................................................................................13
®
CANADIAN GAS ASSOCIATION
A PP R O VED
R
edition of the National Standard of Canada CAN/CGA-B149.1and .2-M91 Natural Gas and Propane Gas Installation Codes
(NSCNGPIC). Wear safety glasses and work gloves. Have fire
extinguisher available during start-up and adjustment procedures
and service calls.
Understand the signal word DANGER, WARNING, or CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards that 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.
NOTE is used to highlight suggestions that will result in enhanced
installation, reliability, or operation.
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 residential construction practices. We require these instructions as a
minimum for a safe installation.
→
Table 1—Clearances From Combustible
Materials (In.)
Sides
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified personnel should install, repair, or service heating equipment.
Back
Top
Front
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.
Vent
Follow all safety codes. In the United States, follow all safety
codes including the National Fuel Gas Code NFPA No. 541992/ANSI Z223.1-1992 (NFGC). In Canada, refer to the current
ama
UNIT SIZE
Single-Wall Vent
Type B-1 Double-Wall Vent
Single-Wall Vent
Type B-1 Double-Wall Vent
Single-Wall Vent
Type B-1 Double-Wall Vent
071
1
0
0
1
6*
3
6
1
091-135
0
0
0
1
6*
3
6
1
NOTES:
1. Provide 30-in. front clearance for servicing. An open door in front of the
furnace can meet this requirement.
2. A minimum clearance of 3 in. must be provided in front of the furnace for
combustion air and proper operation.
INTRODUCTION
→ The
model 58DFA Series 120 Continuous-Pilot Furnaces are
available in sizes 71,000 through 135,000 Btuh input capacities.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
PC 101
Catalog No. 565-812
Printed in U.S.A.
Form 58DF-9SI
Pg 1
11-93
Replaces: 58DF-6SI
Tab 6a 8a
A88324
Fig. 1—Dimensional Drawing
→
Table 2—Dimensions (In.)
UNIT SIZE
A
D
E
VENT CONN SHIP. WT
071-08
14-3/16 12-9/16 12-11/16
4
135
071-12
14-3/16 12-9/16 12-11/16
4
139
091-12
17-1/2 15-7/8
16
4
146
091-16
17-1/2 15-7/8
16
4
146
110-16
17-1/2 15-7/8
16
4
163
110-20
21
19-3/8
19-1/2
4
171
135-20
24-1/2 22-7/8
23
5
182
This furnace must be installed in the downflow configuration
ONLY. Improper installation, adjustment, alteration, service,
maintenance, or use can cause carbon monoxide poisoning,
explosion, fire, electrical shock, or other conditions which
may cause personal injury, loss of life, or property damage.
Consult a qualified installer, service agency, local gas supplier, or your distributor 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. Failure to follow this warning could result
in electrical shock, fire, personal injury, or death.
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.
The design of the downflow gas-fired furnace is A.G.A./C.G.A.
certified for natural and propane gas and for installation on
noncombustible flooring. The furnace may be installed on combustible flooring when installed with the accessory downflow
subbase. This furnace is for installation in alcoves, attics, basements, closets, or utility rooms. The design of this furnace line is
not A.G.A./C.G.A. certified for installation in mobile homes,
recreation vehicles, or outdoors.
Before installing the furnace, refer to the current edition of the
National NFGC. Canadian installations must be installed in
accordance with NSCNGPIC and all authorities having jurisdiction. For further information, the National Fuel Gas Code is
available from National Fire Protection Association Inc., Batterymarch Park, Quincy, MA 02269, American Gas Association, 1515
Wilson Boulevard, Arlington, VA 22209, or from Literature
Distribution.
Reference should also be made to the regulations of the serving gas
supplier and the local building, heating, plumbing, or other codes
in effect in the area in which the installation is made. In the
absence of local codes, the installation must conform with the
NFGC.
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 a maximum of 85° F db.
For accessory installation details, refer to the applicable installation literature.
NOTE: Remove all shipping brackets and materials before operating the furnace.
2
Step 1—Location
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.
GENERAL
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.
Do not install furnace in a corrosive or contaminated atmosphere. Make sure all combustion and circulating air requirements are followed, in addition to all local codes and
ordinances.
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.
Do not use this furnace during construction when adhesives,
sealers, and/or new carpets are being installed. If the furnace
is required during construction, use clean outside air for
combustion and ventilation. Compounds of chlorine and
fluorine when burned with combustion air form acids which
will cause corrosion of the heat exchangers and metal vent
system. Some of these compounds are found in paneling and
dry wall adhesives, paints, thinners, masonry cleaning materials, and many other solvents commonly used in the construction process.
Canadian installations must be installed in accordance with 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, detergents, bleaches, cleaning solvents, salts, air fresheners, and
other household products.
This furnace must be installed so the electrical components are
protected from water.
Locate the furnace close to the chimney/vent and as near the center
of the air distribution system as possible. The furnace should be
installed level.
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.
The operation of exhaust fans, kitchen ventilation fans,
clothes dryers, or fireplaces could create a NEGATIVE
PRESSURE CONDITION at the furnace. Make-up air MUST
be provided for the ventilation devices, in addition to that
required by the furnace.
Provide ample space for servicing and cleaning. Always comply
with the minimum fire protection clearances shown on the unit
rating plate. This furnace shall not be installed directly on
carpeting, tile, or any combustible material. The furnace may be
installed on combustible flooring when installed with the accessory downflow subbase, which is available from your distributor or
branch when required.
All fuel-burning equipment must be supplied with air for combustion 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 avoid pulling air from the burner
area and draft safeguard opening.
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 unit. 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.
The requirements for combustion and ventilation air depend upon
whether the furnace is located in an UNCONFINED or CONFINED space.
UNCONFINED SPACE — An unconfined space must have at
least 50 cu ft for each 1000 Btuh of input for all the appliances
(such as furnaces, clothes dryer, water heaters, etc.) in the space.
3
The size of the openings depends upon whether the air comes from
inside or outside of the structure.
1. All air from inside the structure:
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.)
For Example:
For Example:
58DFA FURNACE
INPUT BTUH
66,000
88,000
110,000
132,000
MINIMUM SQ FT
WITH 7-1/2 FT
CEILING
440
587
734
880
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. A minimum opening with a total of at least 1 sq in. per 5000
Btuh of total input rating for all equipment must be provided.
Return air must not be taken from the room unless an equal or
greater amount of air is supplied to the room.
58DFA FURNACE INPUT BTUH
66,000
88,000
110,000
132,000
FREE AREA PER
OPENING (SQ IN.)
100
100
110
132
If the building is constructed unusually tight, a permanent opening
directly communicating with the outdoors should be provided.
This opening should have a minimum free area of 1 sq in. per 5000
Btuh of total input rating for all equipment in the enclosure.
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.)
CONFINED SPACE — A confined space is defined as one whose
volume is less than 50 cu ft for each 1000 Btuh of the total input
ratings of 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. (See Fig. 2.)
VENT THROUGH ROOF
(CATEGORY I)
DUCTS TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH*
INTERIOR
HEATED
SPACE
12″ MAX
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
UNCONFINED
SPACE
6″ MIN
(FRONT) †
12″ MAX
1 SQ IN.
PER 2000
BTUH*
D
AIR
DUCTS
TO
OUTSIDE
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
12″ MAX
1 SQ IN.
PER 2000
BTUH*
SUPPLY AIR
12″ MAX
* Minimum opening size is 100 square in. with
minimum dimensions of 3-In.
† Minimum of 3-In. when type B-1 vent is used.
SUPPLY AIR
12″
MAX
A RETURN VENT
THROUGH
ROOF
(CATEGORY I)
F
1 SQ IN.
PER 4000
BTUH*
CONFINED
SPACE
RETURN
AIR
E
B
OUTDOORS
1 SQ IN.
PER 4000
BTUH*
G
12″
MAX
C
12″ MAX
DUCT
TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH
*Minimum dimensions of 3-In.
NOTE: Use any of the following
combinations of openings:
A&B C&D D&E F&G
A93387
Fig. 2—Air for Combustion and Ventilation
(Inside Air)
A93388
Fig. 3—Air for Combustion and Ventilation
(Outside Air)
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, assume 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.
4
2. All air from outdoors:
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.
For Example:
58DFA FURNACE INPUT BTUH
66,000
88,000
110,000
132,000
FREE AREA PER
OPENING (SQ IN.)
16.5
22.0
27.5
33.0
ROUND PIPE (IN.
DIA)
5
6
6
7
FURNACE
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.
PLENUM
For Example:
58DFA FURNACE INPUT BTUH
66,000
88,000
110,000
132,000
FREE AREA PER
OPENING (SQ IN.)
33.0
44.0
55.0
66.0
ROUND PIPE (IN.
DIA)
7
8
9
10
A73383
Fig. 5—Furnace on a Concrete Slab (Non-Garage
Installation)
2. When completed, downflow subbase, plenum, and furnace (or
coil casing when used) should be installed as shown in Fig. 6.
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 rectangular ducts must be at least 3 in. (See
Fig. 3.)
Step 3—Supply-Air Plenum Installation
INSTALLATION ON A CONCRETE SLAB
1. Construct hole in floor per dimensions in Fig. 4 and Table 3.
2. Install plenum and furnace as shown in Fig. 5.
FURNACE
(OR COIL CASING
WHEN USED)
A
DOWNFLOW
SUBBASE
B
HOLE IN
FLOOR
SHEET METAL
PLENUM
Fig. 4—Floor Opening for Concrete Slab
A78651
A73382
Fig. 6—Furnace, Plenum, and Subbase Installed on
a Combustible Floor
Table 3—Opening Dimensions
FURNACE CASING
WIDTH
A
14-3/16
17-1/2
21
24-1/2
13-1/8
16-7/16
19-7/8
23-7/16
B
Heat-Only
19-5/8
19-5/8
19-5/8
19-5/8
Heat/Cool*
19-7/16
19-7/16
19-7/16
19-7/16
* These dimensions apply when a model CB or CD Evaporator Coil casing is
to be installed.
INSTALLATION ON A COMBUSTIBLE FLOOR
1. Cut and frame hole in floor per dimensions in Installation
Instructions packaged with downflow subbase.
5
Table 4—Maximum Capacity of Pipe *
NOMINAL IRON
INTERNAL
PIPE SIZE (IN.) DIAMETER (IN.)
DO NOT INSTALL THE FURNACE ON ITS BACK OR
SIDES; safety control operation will be adversely affected.
Never connect return-air ducts to the sides or back of the
furnace. Failure to follow this warning could result in fire,
personal injury, or death.
1/2
3/4
1
1-1/4
1-1/2
Step 4—Filter Arrangement
0.622
0.824
1.049
1.380
1.610
LENGTH
10
20
175 120
360 250
680 465
1400 950
2100 1460
OF PIPE (FT)
30
40 50
97
82 73
200 170 151
375 320 285
770 660 580
1180 990 900
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14-in. wc) or less, and a
pressure drop of 0.5-in. wc (based on a 0.60 specific gravity gas). Ref: Table
C-4 NFPA 54/ANSI Z223.1-1992.
Never operate unit without a filter or with filter access door
removed. Failure to follow this warning could result in fire,
personal injury, or death.
If a flexible connector is required or allowed by the authority
having jurisdiction, black iron pipe shall be installed at the
gas valve and extend a minimum of 2 in. outside the furnace
casing.
The 2 factory-supplied filters are shipped in the blower compartment. After the return-air duct has been connected to the furnace,
install the filters in a V-formation inside the return-air plenum.
(See Fig. 7.)
Piping should be pressure tested in accordance with local and
national plumbing and gas codes before the furnace has been
attached. If the 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 located on the
gas valve before the test. It is recommended that the ground joint
union be loosened before pressure testing.
AIRFLOW
INSTALLATION
POSITION
OF FILTERS
RETURN-AIR
PLENUM
Never purge a line into a combustion chamber. Never use
matches, candles, flame, or other sources of ignition to check
for gas leakage. Use a soap-and-water solution to check for
gas leaks. Failure to follow this warning could result in fire,
explosion, personal injury, or death.
After all connections have been made, purge the lines and check
for gas leakage.
Install a sediment trap in the riser leading to 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. 8.)
Joint compounds (pipe dope) should be applied sparingly and only
to the male threads of the joints. This pipe dope 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, accessible for test gage connection, must be
installed immediately upstream of the gas supply connection to the
furnace and downstream of the manual shut-off valve. Place a
ground joint union between the gas control manifold and the
manual shut-off valve.
ACCESS DOOR
A88486
Fig. 7—Filter Positions
Use the proper length of pipes to avoid stress on the gas
control manifold. Failure to follow this warning could result
in a gas leak causing fire, explosion, personal injury, or death.
Step 5—Gas Piping
Gas piping must be installed in accordance with national and local
codes. Refer to the current edition of the NFGC. Canadian
installations must be installed in accordance with NSCNGPIC and
all authorities having jurisdiction.
Connect the gas pipe to the funace using a backup wrench to
avoid damaging gas controls.
The gas supply line should be a separate line directly from the
meter to the furnace, if possible. Refer to Table 4 for recommended gas pipe sizing. Risers should be used to connect to the
furnace and to the meter.
Step 6—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.
6
115-VAC
NEUTRAL
TERMINALS
115-VAC
LINE
VOLTAGE
115-VAC
TRANSFORMER
1
COM
PR-2
L2
CFR
LO
L1
HFR
PR-1
1
4
7
2
5
8
3
6
9
PL-1
3
HI
9-PIN
CONNECTOR
IDR
HEATING
SPEED TAP
TERMINAL
EAC-1
GAS
SUPPLY
24-VAC COMMON
COOLING
SPEED TAP
TERMINAL
EAC-2
24-VAC POWER
SEC-2
SEC-1
MAX. 1.0 AMPS
115-VAC
W
Y
R
C
G
UNCUT: 120 SEC
FU
CUT: 180 SEC
3-AMP
FUSE
24-VAC FUSE
3-AMP ONLY
GROUND
SCREW
REQUIRED
CES0110074-00
MANUAL
SHUTOFF
VALVE
ELECTRONIC
AIR-CLEANER
TERMINALS
24-VAC
COMMON
24-VAC
THERMOSTAT
TERMINALS
BLOWER
OFF-DELAY
BLOWER
OFF-TIME
ADJUSTMENT
SEDIMENT
TRAP
UNION
A89414
Fig. 8—Typical Gas Pipe Arrangement
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire.
A91226
Fig. 9—Control Center
venting system shall maintain a minimum of 1/4-in. upward slope
per linear ft 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.
The cabinet MUST have an uninterrupted or unbroken ground
according to National Electrical Code ANSI/NFPA 70-1993
and Canadian Electrical 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.
Step 8—Start-up, Adjustment, and Safety Check
GENERAL — The furnace must have a 115-v power supply
properly connected and grounded. Thermostat wire connections at
R,W,C, and Y must be made at the 24-v terminal block on the
control board. The gas service pressure must not exceed 0.5 psig
(14-in. wc), but must be no less than 0.16 psig (4.5-in. wc).
Make all electrical connections in accordance with the current
edition of the National Electrical Code ANSI/NFPA 70-1993 and
any local codes or ordinances that might apply. For Canadian
installations, all electrical connections must be made in accordance
with Canadian Electrical Code CSA C22.1 or authorities having
jurisdiction.
Before operating the furnace, check each manual reset switch for
continuity. If necessary, press the button to reset the switch.
The blower compartment door must be in place to complete the
115-v circuit to the furnace.
24-V WIRING — Make field 24-v connections at the 24-v terminal strip. (See Fig. 9 and 10.) Connect terminal Y as shown for
proper operation in cooling mode. Use only AWG No. 18
color-coded wire.
This furnace is equipped with a fuse link in the gas control
area. The switch will open and shut off power to the gas valve
if a flame rollout or an overheating condition occurs in the gas
control area. DO NOT bypass the switch. Correct inadequate
combustion air supply problem and reset the switches.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the main control board. Any direct shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3-amp fuse of identical size.
SEQUENCE OF OPERATION — Using the schematic diagram,
follow the sequence of operation through the different modes. (See
Fig. 11.)
ACCESSORY
Electronic air cleaner (EAC)
Step 7—Venting
NOTE: When the blower door is in place, 115v is supplied
through blower door switch ILK to heating fan relay HFR, and
transformer TRAN. Transformer TRAN energizes the safety
circuit containing auxiliary limit switch ALS, fuse link FL, and
limit switch LS to energize R.
Refer to the enclosed Installation Instructions, GAMA Venting
Tables for Category I Furnaces and QUIK•VENT™ Tables for
Category I Fan-Assisted Furnaces. The horizontal portion of the
With the furnace pilot lit, the thermocouple will energize the
thermal magnet circuit of gas valve GV, permitting gas flow to the
remaining portion of the gas valve.
Two screw terminals (EAC-1 and EAC-2) are provided for
EAC connection. The terminals are energized with 115-v,
1-amp maximum during blower motor operation.
7
FIELD 24-VOLT WIRING
FIELD 115-, 208/230-, 460-VOLT WIRING
FACTORY 24-VOLT WIRING
FACTORY 115-VOLT WIRING
W
FOUR
WIRE
R
G
Y
THERMOSTAT
TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
TWO-WIRE
HEATINGONLY
BLK
BLK
W
WHT
WHT
R
GND
GND
115-VOLT FIELD- AUXILIARY
J-BOX
SUPPLIED
CONTROL
FUSED
BOX
DISCONNECT
208/230- OR
460-VOLT
THREE
PHASE
G
C
GND
CONDENSING
UNIT
Y
24-VOLT
TERMINAL
BLOCK
FURNACE
208/230VOLT
SINGLE
PHASE
TWO
WIRE
NOTE: Connect Y-terminal as
shown for proper
operation.
NOTE: If any of the original wire,
as supplied, must be replaced, use
same type or equivalent wire.
A78461
→
Table 5—Electrical Data
UNIT SIZE
071-08
071-12
091-12
091-16
110-16
110-20
135-20
VOLTS— OPERATING VOLTAGE RANGE
MAX FUSE OR
MAX WIRE LENGTH
HERTZ—
MAX UNIT AMPS MIN WIRE GAGE
HACR-TYPE CKT
(FT)‡
Max*
Min*
PHASE
BKR AMPS†
115—60—1
127
104
6.7
14
44
15
115—60—1
127
104
8.4
14
35
15
115—60—1
127
104
9.2
14
32
15
115—60—1
127
104
10.2
14
29
15
115—60—1
127
104
10.0
14
30
15
115—60—1
127
104
13.1
12
36
20
115—60—1
127
104
14.3
12
33
20
* Permissible limits of the voltage range at which the unit will operate satisfactorily (assumes full accessory load).
† 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.
Fig. 10—Heating and Cooling Application Wiring Diagram
e. When the thermostat is satisfied, the R-W circuit is broken,
de-energizing both solenoid coils of gas valve GV and the
solid-state time-delay circuit for the fan relay HFR. Gas
flow to the main burners immediately stops. Approximately
120 sec (or 180 sec depending on the blower off time
selected) after main burners are extinguished, heating fan
relay HFR is de-energized and blower motor BLWM stops.
The blower off delay can be permanently changed to 180
sec by cutting resistor. (See Fig. 9.)
f. If the pilot flame is extinguished, the thermocouple no
longer energizes the thermal magnet circuit of gas valve
GV. Gas flow to the pilot and main burners stops until the
pilot is manually relit.
NOTE: When gas valve GV is energized, R-W circuit is closed.
After a power interruption, the gas valve closes within 7 sec and
the furnace skips the blower on delay and immediately starts the
blower.
2. Cooling mode
When the thermostat "calls for cooling" R, G, and Y circuits
close. Simultaneously, the R-Y circuit starts the outdoor
condensing unit, and the R-G circuit energizes cooling fan
relay coil CFR and heating fan relay coil HFR. The normally
open contacts of heating relay HFR and cooling relay CFR
close, energizing the cooling speed of blower motor BLWM.
1. Heating mode
a. When the wall thermostat "calls for heat," the R-W circuit
closes. This closed circuit supplies power to the 24-v safety
circuit containing automatic reset limit switch LS and fuse
link FL.
b. The inducer motor relay coil IDR is energized. Inducer
motor relay contacts in the 115-v circuit close, starting
inducer motor IDM. Simultaneously, another set of contacts in inducer motor relay IDR closes in the 24-v circuit
and locks in until the R and W circuit or safety circuit
opens.
c. As inducer motor IDM comes to speed, pressure switch
PRS actuates and supplies power through manual reset
draft safeguard switch DSS. This process energizes both
solenoid coils in gas valve GV, causing the valve to open
which permits gas flow to the main burners where the gas
is ignited by the pilot.
d. Simultaneously, solid-state time-delay circuit in the blower
control center is energized. Approximately 45 sec after the
R-W circuit is closed, heating fan relay coil HFR is
energized, closing the 115-v contacts of the heating fan
relay HFR and starting blower motor BLWM on heating
speed. EAC terminals energize with 115v when the blower
is operating in either heating or cooling speed.
8
9
BLWM
CAP
CFR
DSS
EAC-1
EAC-2
FU1
FU2
FL
GV
HFR
IDM
IDR
ILK
JB
LS
PCB
PL1
PL2
PL4
PRS
TRAN
LEGEND
ALS
CAP
BRN
BLWM
FU2
2
1
C
BLK
WHT
JB
ILK
NOTE #5
EAC-2
W
EAC-1
HI
L1
Y
R
NOTE #10
HFR
TRAN
CFR
LO
COM
PR2 L2
PL2
BLK 1
2
WHT
AUX. LIMIT SWITCH (OVER TEMP), SPST-(N.C.),
MANUAL RESET
BLOWER MOTOR
CAPACITOR
COOLING FAN RELAY, SPDT
DRAFT SAFEGUARD SWITCH, SPST-(N.C.), MANUAL RESET
ELECTRONIC AIR CLEANER CONNECTION (115VAC)
ELECTRONIC AIR CLEANER CONNECTION (COMMON)
FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE
FUSE, FIELD INSTALLED
FUSIBLE LINK
GAS VALVE, (REDUNDANT)
HEATING FAN RELAY, SPST (N.O.)
INDUCED DRAFT MOTOR
INDUCER DRAFT RELAY, DPST-(N.O.)
BLOWER DOOR INTERLOCK SWITCH, SPST-(N.O.)
JUNCTION BOX
LIMIT SWITCH (OVER TEMP), SPST-(N.C.), AUTO RESET
PRINTED CIRCUIT BOARD (FURNACE CONTROL)
9-CIRCUIT CONNECTOR (PCB1)
2-CIRCUIT CONNECTOR (L1, L2)
5-CIRCUIT PLUG CONNECTOR (BLWM)
PRESSURE SWITCH, SPDT
TRANSFORMER (115VAC/24VAC)
BRN
GRN
NOTE #4
PL4
4
3 RED
LO
MED LO
MED HI
HI
COM
GRN
WHT
BLK
FUSED DISCONNECT
SWITCH (WHEN REQ'D)
IDM
RED
WHT
BLK
WHT
WHT
(WHEN USED)
NOTE #7
ALS
BLU
FL
LS
DSS
IDR
3AMP
FUSE
NOTE #8
FU1
PL1 1 4 7
2 5 8
3 6 9
GROUND
SCREW
REQ'D
SEC-1
SEC-2
NC
NO
FIELD WIRING SCREW TERMINAL
PLUG RECEPTACLE
FIELD SPLICE
EQUIPMENT GROUND
FIELD GROUND
C
PCB
NOTE #1
PRS
JUNCTION
TERMINAL
PCB TERMINAL
FACTORY POWER WIRING (120VAC)
FACTORY CONTROL WIRING (120VAC)
FIELD POWER WIRING (120VAC)
CONDUCTOR ON PCB
G
BRN
BLU
BRN
ORN
Fig. 11—Unit Wiring Diagram
C
NOTE #9
PR1
BLK
PILOT
BLK
TH
BLK
GV
MGV
BLU
RED
TR
WHT
RED
RED
CONNECTION
DIAGRAM
YEL
HFR
L2
NOTE #1
PL1-6
FL
CFR
PRS
EAC-2
PL1-4
COM
IDR
C
DSS
NOTE #10
4
3
2
1
C
FU1
PR-1
TRAN
115VAC
BLWM
TH
HFR
PILOT
IDR
TR
MGV GV
TIME
DELAY
LOGIC
PL1-8
SEC-2
PR-2
IDM
SCHEMATIC
DIAGRAM
3A
SEC-1 24VAC
FUSE
NOTE#8
PL1-1
PL1-3
CAP
LO
MED LO
MED HI
HI
COM
PL4
NOTE#4
PL1-2
(WHEN USED)
NOTE #7
ALS
EAC-1
CFR
EQUIPMENT GROUND
TO 115V AC FIELD DISCONNECTIONS
NOTE #5
PL1-9
NO
NC
LS
IDR
NOTE#10
L1
L2
A92176
NOTES:
1. INTERNALLY CONNECTED TO EQUIPMENT GROUND THROUGH MOUNTING SCREW.
2. IF ANY OF THE ORIGINAL EQUIPMENT WIRE IS REPLACED, USE WIRE RATED FOR
105° C.
3. BLOWER MOTOR (BLWM) & INDUCER MOTOR (IDM) CONTAIN AUTO-RESET
THERMAL OVERLOAD SWITCH.
4. BLOWER MOTOR FACTORY SPEED SELECTIONS (PL4) ARE FOR AVERAGE
CONDITIONS. SEE INSTALLATION INSTRUCTIONS FOR DETAILS ON OPTIMUM
SPEED SELECTIONS.
5. USE ONLY COPPER WIRE BETWEEN THE DISCONNECT SWITCH AND THE
FURNACE JUNCTION BOX (JB).
6. SYMBOLS ARE ELECTRICAL REPRESENTATIONS ONLY.
7. AUXILIARY LIMIT SWITCH (ALS) USED ON DOWNFLOW MODELS ONLY.
8. THE TRANSFORMER 24VAC WINDING IS PROTECTED BY A 3 AMP AUTOMOTIVE
BLADE TYPE FUSE ON THE CONTROL BOARD. A 24VAC SHORT TO GROUND
DURING INSTALLATION, CHECKOUT, OPERATION, SERVICE OR MAINTENANCE
COULD CAUSE THIS FUSE TO OPEN. DO NOT REPLACE THE 3 AMP FUSE
WITH ANY OTHER SIZE FUSE.
9. BLOWER MOTOR (BLWM) ADJUSTABLE OFF-DELAY. FACTORY SET: 120 SECS.
CUT RESISTOR: 180 SECS.
10. WHEN CFR RELAY IS ENERGIZED, HFR RELAY IS ALSO ENERGIZED.
319593-401 REV. C
C
G
W
Y
R
PL1-7
L1
PL2
ILK
(1.) Check and verify orifice size in furnace. NEVER
ASSUME THE ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
The EAC terminals are energized with 115v when the blower
is operating on either heating or cooling speed.
3. Continuous blower mode
When the R-G circuit is made, the blower motor will operate
on cooling speed. During a call for heat, the blower stops,
allowing the furnace heat exchangers to heat up more quickly.
When the blower motor comes back on, it runs on heating
speed. The blower reverts to continuous operation after the
heating cycle blower off delay is completed.
DO NOT redrill burner orifices. Improper drilling (burrs,
out-of-round holes, etc.) can cause excessive burner noise and
misdirection of burner flames. This can result in flame
impingement of the burners and heat exchangers causing
failure.
START-UP PROCEDURES
NOTE: If orifice hole appears damaged or is suspected to have
been redrilled, check the orifice hole with the correct size
numbered drill bit. Never redrill an orifice. A burr-free and
squarely aligned orifice hole is essential for proper flame characteristics.
Ensure that all connections have been properly made.
Light the pilot using the procedures outlined on the
lighting/operating instruction label attached to the furnace. However, when lighting the pilot for the first time, perform the
following additional steps:
(2.) Find natural gas heat value and specific gravity in
Table 6.
1. After all connections have been made, purge the lines and
check for leaks.
(3.) 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.
Never purge a line into a combustion chamber. Never use
matches, candles, flame or other sources of ignition to check
for gas leakage. Use a soap-and-water solution to check for
gas leaks. Failure to follow this warning could result in fire,
explosion, personal injury, or death.
EXAMPLE:
Heat value 980 Btu/cu ft
Specific gravity 0.58
Therefore; Orifice No. 42 *
Manifold pressure 3.5-in. wc
* The furnace is shipped with No. 44 orifices. Therefore, in
this example all main burner orifices must be changed and
the manifold pressure must be adjusted.
2. Allow 5 minutes to elapse after purging gas lines, then light
pilot in accordance with lighting/operating instructions on the
furnace.
The pilot flame should be soft blue in color and surround 3/8
to 1/2 in. of the thermocouple element tip. The flame must
never come in contact with any other part of the thermocouple
or its lead wire. The flame should merge with the carryover
flame. When the pilot flame requires adjustment:
(4.) Proceed to item c. to adjust manifold pressure.
b. Check gas input rate by clocking gas meter.
(1.) Obtain average yearly heat value for local gas supply.
a. Locate adjustment screw on top of main gas valve next to
pilot tube. (See Fig. 12.)
NOTE: Be sure heating value of gas used for calculation is
correct for altitude. Consult local gas utility for altitude adjustment
of gas heating value.
b. Remove capscrew and turn adjustment screw clockwise
(in) to decrease pilot gas flow.
(2.) Turn off all other gas appliances and pilots.
c. When proper adjustment is obtained, replace capscrew.
(3.) Start furnace and let run for 3 minutes.
3. Allow 5 minutes for pilot to establish a draft before operating
furnace.
(4.) Measure time (in sec) for gas meter to complete 1
revolution.
4. To operate furnace, follow procedures on lighting instruction
label attached to furnace.
(5.) Refer to Table 7 for cu ft of gas per hr.
5. With furnace operating, set thermostat below room temperature and observe that furnace goes off. Set thermostat above
room temperature and observe that furnace restarts.
(6.) Multiply gas rate (cu ft/hr) by heating value (Btu/cu
ft).
EXAMPLE:
Btu 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 X 1070 = 107,000 Btuh
ADJUSTMENTS
1. Set gas input rate.
There are 2 methods of adjusting the gas input rate. The
preferred method is by using Table 6 and item a. The second
method is by clocking the gas meter and item b.
The gas valve regulator has been nominally set at 3.5-in. wc
for natural gas. When adjusting input rate, do not set manifold
pressure above 3.8-in. wc or below 3.2-in. wc.
(7.) Measured gas input should not exceed gas input on
unit rating plate.
(8.) Proceed to item c. to adjust manifold pressure.
a. Check gas input rate using Table 6.
c. Adjust gas input.
(1.) Obtain average yearly heat value for local gas supply.
(1.) Remove regulator adjustment seal cap. (See Fig. 12.)
(1.) Obtain average yearly specific gravity for local gas
supply.
(2.) Turn adjusting screw counterclockwise to decrease
input. Turn screw clockwise to increase input and
counterclockwise to decrease input. DO NOT set
manifold pressure less than 3.2-in. wc or more than
(1.) Verify furnace model. Table 6 can only be used for
model 58DFA Furnaces.
10
Table 6—Model 58DFA Orifice Size and Manifold Pressure for Correct Input Rate
(Tabulated Data Based on Altitude Up to 2000 Ft and 22,000 Btuh Per Burner)
SPECIFIC GRAVITY OF NATURAL GAS
GAS HEAT VALUE
0.56
0.58
0.60
0.62
0.64
0.66
0.68
0.70
0.72
(BTU/CU FT)
Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld Orf Mnfld
No. Press. No. Press. No. Press. No. Press. No. Press. No. Press. No. Press. No. Press. No. Press.
41
3.2
41
3.3
41
3.4
41
3.5
41
3.7
41
3.8
39
3.4
38
3.2
38
3.3
860
42
3.6
42
3.7
42
3.8
40
3.3
39
3.2
39
3.3
40
3.6
39
3.5
39
3.6
—
—
—
—
40
3.2
—
—
40
3.4
40
3.5
—
—
40
3.7
40
3.8
42
3.4
41
3.2
41
3.3
41
3.4
41
3.5
41
3.6
41
3.8
39
3.3
38
3.2
875
—
—
42
3.6
42
3.7
42
3.8
40
3.3
39
3.2
39
3.3
40
3.6
39
3.4
—
—
—
—
—
—
40
3.2
—
—
40
3.4
40
3.5
—
—
40
3.7
42
3.3
42
3.4
41
3.2
41
3.3
41
3.4
41
3.5
41
3.6
41
3.7
41
3.8
890
—
—
—
—
42
3.6
42
3.7
42
3.8
40
3.2
40
3.3
39
3.2
39
3.3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
40
3.4
40
3.5
42
3.2
42
3.3
42
3.4
41
3.2
41
3.3
41
3.4
41
3.5
41
3.6
41
3.7
905
—
—
—
—
—
—
42
3.6
42
3.7
42
3.8
40
3.2
40
3.3
39
3.2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
40
3.4
43
3.8
42
3.2
42
3.3
42
3.4
41
3.2
41
3.3
41
3.4
41
3.5
41
3.6
920
—
—
—
—
—
—
—
—
42
3.5
42
3.7
42
3.8
40
3.2
40
3.3
43
3.7
43
3.8
42
3.2
42
3.3
42
3.4
41
3.2
41
3.3
41
3.4
41
3.5
935
—
—
—
—
—
—
—
—
—
—
42
3.5
42
3.7
42
3.8
40
3.2
43
3.6
43
3.7
43
3.8
42
3.2
42
3.3
42
3.4
41
3.2
41
3.3
41
3.4
950
—
—
—
—
—
—
—
—
—
—
—
—
42
3.5
42
3.6
42
3.7
43
3.4
43
3.6
43
3.7
43
3.8
42
3.2
42
3.3
42
3.4
41
3.2
41
3.3
965
—
—
—
—
—
—
—
—
—
—
—
—
—
—
42
3.5
42
3.6
44
3.8
42
3.5
43
3.6
43
3.7
43
3.8
42
3.2
42
3.3
42
3.4
41
3.2
980
43
3.3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
42
3.5
44
3.7
44
3.8
43
3.5
43
3.6
43
3.7
43
3.8
42
3.2
42
3.3
42
3.4
995
43
3.2
43
3.4
—
—
—
—
—
—
—
—
—
—
—
—
—
—
44
3.6
44
3.7
44
3.8
43
3.5
43
3.6
43
3.7
43
3.8
42
3.2
42
3.3
1010
—
—
43
3.3
43
3.4
—
—
—
—
—
—
—
—
—
—
—
—
44
3.5
44
3.6
44
3.7
43
3.4
43
3.5
43
3.6
43
3.7
43
3.8
43
3.2
1025
—
—
43
3.2
43
3.3
—
—
—
—
—
—
—
—
—
—
—
—
44
3.4
44
3.5
44
3.6
44
3.7
43
3.4
43
3.5
43
3.6
43
3.7
43
3.8
1040
—
—
—
—
43
3.2
43
3.3
—
—
—
—
—
—
—
—
—
—
44
3.3
44
3.4
44
3.5
44
3.6
44
3.8
43
3.4
43
3.5
43
3.6
43
3.7
1055
—
—
—
—
—
—
43
3.2
43
3.3
—
—
—
—
—
—
—
—
44
3.2
44
3.3
44
3.4
44
3.5
44
3.7
44
3.8
43
3.4
43
3.5
43
3.6
1070
—
—
—
—
—
—
—
—
43
3.2
43
3.3
—
—
—
—
—
—
45
3.8
44
3.2
44
3.3
44
3.4
44
3.6
44
3.7
44
3.8
43
3.4
43
3.5
1085
—
—
—
—
—
—
—
—
—
—
43
2.3
43
3.3
—
—
—
—
45
3.7
45
3.8
44
3.2
44
3.4
44
3.5
44
3.6
44
3.7
44
3.8
43
3.4
1100
—
—
—
3.4
—
—
—
—
—
—
—
—
43
3.2
43
3.3
—
—
3.8-in. wc for natural gas. Make any major adjustments by changing main burner orifices.
REGULATOR
ADJUSTMENT
SEAL CAP
(3.) When correct input is obtained, replace regulator seal
cap. Main burner flame should be clear blue, almost
transparent. (See Fig. 13.)
INLET
PRESSURE
TAP
d. High altitudes—In the U.S.A., gas input on rating plate is
for altitudes up to 2000 ft. Ratings for altitudes over 2000
ft must be 4 percent less for each 1000 ft above sea level.
To obtain the adjusted altitude rating, adjust the manifold
pressure, item c., and replace the main burner orifice as
needed. Refer to NFGC Appendix F, Table F-4 for proper
orifice sizing at high altitudes.
MANUAL
ON/OFF
KNOB
ON
OFF
PILOT
MANIFOLD
PRESSURE
TAP
PILOT TUBE
CONNECTION
PILOT
ADJUSTMENT
SCREW
e. Canadian installations only—The Canadian ratings are
approved for altitudes up to 2000 ft for natural and propane
gases. High-altitude ratings are from 2001 ft to 4500 ft
above sea level. High-altitude input ratings include a 10
percent derate as required by Canadian standards. (See
Table 8.)
THERMOCOUPLE
CONNECTION
2. Set temperature rise.
A89171
Do not exceed the temperature rise range specified on the unit
rating plate. Determine the air temperature rise as follows:
Fig. 12—Redundant Automatic Gas Valve
11
PILOT FLAME
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine temperature rise.
BURNER FLAME
c. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise.
BURNER
Disconnect the electrical power before changing the speed
tap. A failure to follow this warning could result in personal
injury.
d. To change motor speed taps, remove the motor tap lead and
relocate it on the desired terminal on the plug-in terminal
block/speed selector located on the blower housing. (See
Table 9.)
Table 8—Canadian Orifice Size
SEA LEVEL
0—2000
44
54
GAS
Natural
Propane
MANIFOLD
Table 9—Speed Selector
A84076
Fig. 13—Burner Flame
SPEED
Common
High
Med-High
Med-Low
Low
Table 7—Gas Rate Cu Ft/Hr
SIZE OF TEST DIAL
SIZE OF TEST DIAL
SECONDS
SECONDS
FOR 1
FOR 1
1
2
5
1
2
5
REVOLUTION cu ft cu ft
cu ft REVOLUTION cu ft
cu ft
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
1000
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
HIGH ALTITUDE
2001—4500 FT
45
55
TAP NO.*
C
1
2
3
4
* White wire from control box to common; black wire from control box to cooling
speed selection; red wire from control box to heating and constant fan 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 or above.
3. Set thermostat heat anticipator
The thermostat heat anticipation must be set to match the amp
draw of the electrical components in the R-W circuit. Accurate
amp draw readings can be obtained at thermostat subbase
terminals R and W. Fig. 14 illustrates an easy method of
obtaining the actual amp draw. The amp reading should be
taken after the blower motor has started. See the thermostat
manufacturer’s instructions for adjusting the heat anticipator
and for varying the heating cycle length.
NOTE: When using an electronic thermostat, set cycle rate for 3
cycles per hr.
CHECK SAFETY CONTROLS
1. Check operation of gas shut-off control for 100 percent
shutoff.
NOTE: The furnace pilot must be lit so the thermocouple
energizes the thermal magnet circuit of gas valve GV, which
permits gas flow to the remaining portion of the valve.
If the pilot flame is extinguished, the thermocouple will no
longer energize the thermal magnet circuit of the gas valve.
Gas flow to the pilot and main burners will cease until the pilot
is manually relit.
a. With furnace operating, unscrew pilot thermocouple lead
from gas valve. The pilot and main burner gas must shut
off. No gas should flow through valve.
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. After valve is found to operate satisfactorily, reconnect
thermocouple to gas valve (fingertight position only).
12
e. Wait 5 minutes and then reset draft safeguard switch.
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
4. Check pressure switch.
This control proves operation of draft inducer blower.
HOOK-AROUND
VOLT/AMMETER
a. Turn off 115-v power to furnace.
b. Remove control door and disconnect inducer motor lead
wires from wire harness.
R Y W G
c. Turn on 115-v power to furnace.
d. Close thermostat switch as if making normal furnace start.
If the burners do not light, the pressure switch is functioning properly.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace control door, and
turn on 115-v power.
A80201
Fig.
10Draw
TURNSCheck
14—Amp
With Ammeter
5. Check auxiliary limits.
c. Tighten thermocouple connection 1/4 turn with wrench.
a. Turn off 115-v power to furnace.
FROM UNIT 24-VOLT
d. Relight pilot by following
the BLOCK
lighting instructions on the
TERMINAL
furnace.
5.0 AMPS ON AMMETER
2.EXAMPLE:
Check primary
control.
10 TURNSlimit
AROUND
JAWS
b. Remove blower access door.
c. Disconnect red motor lead at blower speed selector. Mark
terminal for proper reconnection.
= 0.5 AMPS FOR THERMOSTAT SETTING
This control shuts off the combustion control system and
energizes the circulating-air blower motor if the furnace
overheats.
d. Replace blower access door.
e. Turn on 115-v power to furnace. Be sure room thermostat
is calling for heat.
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.
f. Allow furnace to operate until auxiliary limit activates, but
DO NOT operate furnace longer than 4 minutes.
g. If furnace operates for 4 minutes, check/replace auxiliary
limit switch.
h. Turn off 115-v power to furnace.
i. Remove blower access door.
3. Check draft safeguard switch.
j. Reconnect red motor lead and replace door.
The purpose of this control is to permit the safe shutdown of
the furnace during certain blocked vent conditions.
k. Turn on 115-v power to furnace.
CHECKLIST
a. Disconnect power to furnace and remove vent connector
from furnace outlet collar. Be sure to allow time for vent
pipe to cool down before removing.
1. Put away tools and instruments, and clean up debris.
2. Verify manual reset switches have continuity.
b. Set room thermostat above room temperature and restore
power to furnace.
3. Ensure blower and control access doors are properly installed.
c. After normal startup, allow furnace to operate for 2
minutes, then block flue outlet (50 percent). Furnace should
cycle off within 3 minutes.
5. Check operation of accessories per manufacturer’s instructions.
4. Cycletest furnace with room thermostat.
6. Review User’s Manual with owner.
d. Remove blockage and reconnect vent pipe to furnace outlet
collar.
7. Leave literature packet near furnace.
13
Copyright 1993 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231
35006c
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
PC 101
Catalog No. 565-812
Printed in U.S.A.
Form 58DF-9SI
Pg 14
11-93
Replaces: 58DF-6SI
Tab 6a 8a