58DFA, 58GFA
Induced-Combustion Furnaces
Service and Maintenance Instructions
→
For Sizes 065-150 Series 120
NOTE: Read the entire instruction manual before starting the
installation.
Index
Page
CANADIAN GAS ASSOCIATION
ama
SAFETY CONSIDERATIONS.....................................................1
CARE AND MAINTENANCE..................................................1-8
Air Filter Arrangement..........................................................2-3
Blower Motor and Wheel......................................................3-4
Cleaning Heat Exchanger......................................................4-5
Electrical Controls and Wiring .............................................5-6
Pilot ...........................................................................................6
Troubleshooting ........................................................................6
Unit Wiring Diagram................................................................7
Troubleshooting Chart ..............................................................8
®
A PPROVED
R
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person-
nel 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, follow all safety
codes including the National Fuel Gas Code NFPA No. 54-
1992/ANSI Z223.1-1992 (NFGC). In Canada, refer to the current
edition of the National Standard of Canada CAN/CGA-B149.1-
and .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.
Fig. 1—Model 58AD9F20A58-
Downflow
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 word DANGER, WARNING, or 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 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 sugges-
tions that will result in enhanced installation, reliability, or
operation.
Fig. 2—Model 58GFA UpflAo9w2057
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book
Tab 6a 8a
1
4
PC 101
Catalog No. 565-801
Printed in U.S.A.
Form 58D,G-3SM
Pg 1
11-93
Replaces: 58D,G-2SM
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MOUNTING
SCREWS
DRAFT
SAFEGUARD
SWITCH
AUXILIARY
LIMIT SWITCH
(NOT VISIBLE)
FLUE
COLLECTOR
BOX
RELIEF
BOX
SPEED
SELECTOR
VENT PIPE
ENCLOSURE
GAS
VALVE
MOUNTING
SCREWS
CONTROL
BOX
PILOT
DRAFT
SAFEGUARD
SWITCH
CONTROL
BOX
RELIEF
BOX
SPEED
SELECTOR
FLUE
COLLECTOR
BOX
FILTER
RETAINER
WASHABLE
FILTER
A92178
A92179
Fig. 4—Model 58GFA Upflow
b. Remove blower access door after removing 2 screws.
Fig. 5—Model 58DFA Downflow
BLOWER MOTOR AND WHEEL — For long life, economy, and
high efficiency, clean accumulated dirt and grease from the blower
wheel and motor annually.
c. Reach up behind top plate, tilt filters toward center of
return-air plenum, remove filters, and replace or clean as
needed.
The following steps should be performed by a qualified service
technician:
d. Furnaces are equipped with permanent, washable filters.
Clean filters with tap water. Spray water through filter in
opposite direction of airflow.
Some motors have prelubricated sealed bearings and require no
lubrication. These motors can be identified by the absence of oil
ports on each end of the motor. For motors with oil ports, lubricate
motor every 5 years if motor is used on intermittent operation
(thermostat FAN switch in AUTO position), or every 2 years if
motor is in continuous operation (thermostat FAN switch in ON
position).
e. Rinse and let dry. Oiling or coating of filters is not
recommended or required.
f. Reinstall filters.
g. Replace access door and secure with 2 screws.
h. Restore electrical power to furnace.
Remember to disconnect the electrical supply before removing
access doors.
2. Upflow
Each furnace requires 1 or 2 filters which are installed in the
blower compartment. (See Fig. 4.)
Clean and lubricate as follows:
1. Remove 2 screws from blower access door (downflow furnace
only). Remove blower access door.
To remove filters for cleaning or replacement, proceed as
follows:
2. Remove vent pipe enclosure (downflow furnace only) and
disconnect short piece of vent pipe from relief box.
a. Disconnect electrical power before removing access doors.
b. Remove blower and control access doors.
3. Disconnect wires from auxiliary limit on blower housing
(downflow furnace only).
c. Release filter retainer from clip at front of furnace casing.
(See Fig. 4.) For side return, clips may be used on either or
both sides of the furnace.
4. Remove control box.
d. Slide filter out.
5. Remove electrical leads from numbered side of blower speed
selector. (See Fig. 4 and 5.) Note location of wires for
reassembly.
e. Furnaces are equipped with permanent, washable filters.
Clean filter with tap water. Spray water through filter in
opposite direction of airflow.
6. Remove screws holding blower assembly to blower deck and
slide blower assembly out of furnace.
f. Rinse and let dry. Oiling or coating of filter is not
recommended or required.
7. Squeeze side tabs of blower speed selector and pull it out of
blower housing.
g. Reinstall filter.
h. Replace access doors.
i. Restore electrical power to furnace.
8. Loosen screw in strap holding motor capacitor to blower
housing and slide capacitor out from under strap.
3
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9. Mark blower wheel, motor, and motor support in relation to
blower housing before disassembly to ensure proper reassem-
bly.
3. Remove vent pipe enclosure (downflow furnace only) and
disconnect vent pipe from relief box.
4. Remove 2 screws that secure relief box. (See Fig. 4 or 5.)
5. Disconnect wires to the following components:
a. Draft safeguard switch
10. Loosen setscrew holding blower wheel on motor shaft.
11. Remove bolts holding motor mount to blower housing and
slide motor and mount out of housing. Disconnect ground wire
attached to blower housing before removing motor.
b. Inducer motor
c. Pressure switch
12. Lubricate motor (when oil ports are provided).
d. Limit overtemperature switch
e. Gas valve
a. Remove dust caps or plugs from oil ports located at each
end of motor.
f. Edge connector leading to control box
b. Use a good grade of SAE 20 nondetergent motor oil and
put 1 teaspoon, 5 cc, 3/16 oz, or 16 to 25 drops in each oil
port. Do not over-oil.
6. Remove 8 screws that secure flue collector box to center
panel. Be careful not to damage sealant.
c. Allow time for total quantity of oil to be absorbed by each
bearing.
7. Remove complete inducer assembly from furnace, exposing
flue openings.
d. Wipe excess oil from motor housing.
e. Replace dust caps or plugs on oil ports.
13. Remove blower wheel from housing.
a. Mark cutoff location to ensure proper reassembly.
8. Clean cells as follows using field-provided small wire brush,
steel spring cable, reversible electric drill, and vacuum
cleaner.
a. Assemble wire brush and steel spring cable.
(1.) Use 48 in. of 1/4-in. diameter high-grade steel spring
cable (commonly known as drain clean-out or Roto-
Rooter cable).
b. Remove screws holding cutoff plate and remove cutoff
plate from housing.
c. Lift blower wheel from housing through opening.
(2.) Use 1/4-in. diameter wire brush (commonly known as
25-caliber rifle cleaning brush).
14. Clean blower wheel and motor using a vacuum cleaner with
soft brush attachment. Do not remove or disturb balance
weights (clips) on blower wheel blades. The blower wheel
should not be dropped or bent as balance will be affected.
NOTE: The items needed in steps (1.) and (2.) can usually be
purchased at local hardware stores.
(3.) Insert twisted wire end of brush into end of steel spring
cable, and crimp tight with crimping tool or strike with
ball-peen hammer. TIGHTNESS is very important.
15. Reinstall blower wheel by reversing steps 13 a. through c. Be
sure wheel is positioned for proper rotation.
16. Reassemble motor and blower by reversing steps 5 through
11. If motor has ground wire, be sure it is connected as before.
(4.) Remove metal screw fitting from wire brush to allow
insertion into cable.
b. Clean each heat exchanger cell.
Be sure the motor is properly positioned in the blower
housing. The motor oil ports must be at a minimum of 45°
above the horizontal centerline of the motor after the blower
assembly has been reinstalled in the furnace.
(1.) Attach variable-speed, reversible drill to end of steel
spring cable (end opposite brush).
(2.) Insert brush end of cable into upper opening of cell
and slowly rotate with drill. DO NOT force cable.
Gradually insert at least 36 in. of cable into 2 upper
passes of cell. (See Fig. 6.)
17. Reinstall blower assembly in furnace. Connect electrical leads
to blower speed selector. Connections are polarized for
assembly. DO NOT FORCE.
18. Reinstall control box.
19. Reconnect wires to auxiliary limit switch on blower housing
(downflow furnace only).
20. Reinstall vent pipe and enclosure (downflow furnaces only).
21. Turn on electrical power and check for proper rotation and
speed changes between heating and cooling.
22. Replace blower access door and secure with 2 screws (down-
flow furnace only).
CLEANING HEAT EXCHANGER
The following steps should be performed by a qualified service
technician:
A91252
NOTE: Deposits of soot and carbon indicate the existence of a
problem which needs to be corrected. Take action to correct the
problem.
Fig. 6—Cleaning Heat Exchanger Cell
(3.) Work cable in and out of cell 3 or 4 times to obtain
sufficient cleaning. DO NOT pull cable with great
force. Reverse drill and gradually work cable out.
If it becomes necessary to clean the heat exchanger because of
carbon deposits, soot, etc., proceed as follows:
(4.) Remove burner assembly and cell inlet plates.
1. Turn off gas and power to furnace.
2. Remove 2 screws from blower access door (downflow furnace
only). Remove control and blower access doors.
(5.) Replace screws in center panel and cells before
cleaning.
4
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PILOT HEAD V–NOTCH FALLS
DIRECTLY BELOW FRONT EDGE
OF BURNER CARRYOVER.
1
/ ″
8
A91249
Fig. 7—Position of Pilot to Burner
(6.) Insert brush end of cable in lower opening of cell, and
proceed to clean 2 lower passes of cell in same manner
as 2 upper passes.
18. Replace control access door.
ELECTRICAL CONTROLS AND WIRING
NOTE: There may be more than 1 electrical supply to unit.
(7.) Repeat foregoing procedures until each cell in furnace
has been cleaned.
The electrical ground for 115-v wiring must be maintained
properly. Refer to Fig. 8 for field wiring information and to Fig. 9
for unit wiring information.
(8.) Remove residue from each cell using vacuum cleaner.
(9.) Clean burner assembly using vacuum cleaner with soft
brush attachment.
With power disconnected to unit, check all electrical connections
for tightness. Tighten all screws on electrical connections. If any
smoky or burned connections are noticed, disassemble the connec-
tion, clean all parts and stripped wire, and reassemble properly and
securely. Electrical controls are difficult to check without proper
instrumentation; therefore, reconnect electrical power to unit and
observe unit through 1 complete operating cycle.
(10.) Reinstall cell inlet plates and burner assembly. Care
must be exercised to center the burners in the cell
openings.
9. After cleaning flue openings, check sealant on flue collector to
ensure that it has not been damaged. If new sealant is needed,
contact your dealer or distributor.
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.
10. Clean and replace flue collector assembly, making sure all 8
screws are secure.
11. Reinstall 2 screws in relief box.
12. Reconnect wires to the following components:
a. Draft safeguard switch
PILOT — Check the pilot and clean if necessary at the beginning
of each heating season. The pilot flame should be high enough for
proper impingement of the flame-sensing element (or thermo-
couple) and to light the burners. Remove the accumulation of soot
and carbon from the flame-sensing element (or thermocouple).
Refer to Fig. 7 for proper location of pilot on burner assembly.
b. Inducer motor
c. Pressure switch
d. Limit overtemperature switch
e. Gas valve
TROUBLESHOOTING — Page 8 contains a troubleshooting
chart. This chart can be a useful tool in isolating furnace operation
problems. Beginning with the word ‘‘Start,’’ answer each question
and follow the appropriate arrow to the next item.
f. Edge connector leading to control box
13. Reconnect vent pipe to relief box. Replace vent pipe enclosure
(downflow furnace only).
14. Replace blower access door only and secure with 2 screws
(downflow furnace only).
The chart will help identify the problem or failed component. After
replacing any component, verify correct operating sequence as
indicated by bold arrows.
15. Turn on electrical power and gas.
16. Set thermostat and check furnace for proper operation.
Never use a match or other open flame to check for gas leaks.
Use a soap-and-water solution. A failure to follow this
warning could result in fire, personal injury, or death.
17. Check for gas leaks.
5
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FIELD 24-VOLT WIRING
FIELD 115-, 208/230-, 460-VOLT WIRING
FACTORY 24-VOLT WIRING
FACTORY 115-VOLT WIRING
THERMOSTAT
TERMINALS
W
R
G
Y
FOUR
WIRE
FIELD-SUPPLIED
FUSED DISCONNECT
TWO-WIRE
HEATING-
ONLY
208/230- OR
460-VOLT
THREE
PHASE
W
R
BLK
BLK
WHT
WHT
208/230-
VOLT
SINGLE
PHASE
GND
GND
G
AUXILIARY
J-BOX
115-VOLT FIELD-
SUPPLIED
FUSED
DISCONNECT
C
Y
GND
CONTROL
CONDENSING
UNIT
BOX
TWO
24-VOLT
NOTE: If any of the original wire,
as supplied, must be replaced, use
same type or equivalent wire.
WIRE
TERMINAL
BLOCK
NOTE: Connect Y-terminal as
shown for proper
FURNACE
operation.
A78461
Fig. 8—Heating and Cooling Application Wiring Diagram
6
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Y E L
O R N
B R N
B L U
R E D
R E D
W H T
B L K
R E D
B L U
B L K
B L K
W H T
R E D
W H T
7
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START
Turn on 115-VAC
power to unit.
Disconnect all thermostat
wires from board.
Turn off 115-VAC
power to unit.
NO
Are
Is 24VAC
across screws
W & C or
all thermostat
wires to board
disconnected?
Is 24VAC
across screws
R & C?
YES
YES
YES
Is blower
running?
G & C?
NO
NO
NO
YES
Check/Replace:
1. Limit switch
Jumper across
screws R & G.
Replace
board.
2. Limit shield (if used)
3. Fuse link
4. Auxillary limit switch (if used)
5. Wire harness
YES
Is
Is
Is
Is
YES
NO
NO
24VAC
115VAC
across HI &
COM?
115VAC
across L1 &
L2?
blower running
on cooling
speed?
across screws
R & C?
YES
YES
NO
NO
Replace
blower motor
and/or start
capacitor.
Check/Replace:
1. Unit power
2. Door switch
3. Power harness
Check/Replace:
1. 3-amp board
fuse
Is
NO
115VAC
Replace
board.
across EAC-1
& COM?
2. Transformer
Check pressure
tube for leak or
YES
Is
24VAC
NO
crimp; otherwise,
Replace
board.
Remove
R & G jumper.
across PL1-2
& screw C on
board?
replace pressure switch
NO
YES
YES
Is heat
exchanger
pressure drop greater
than 0.35-in.
wc?
Is 24VAC
across pressure
switch N/O contact
& screw C on
board?
Repair wire
harness.
Does
blower turn
off?
YES
NO
NO
NO
YES
Check/Replace:
1. Vent systems
2. Induce wheel
Is 24VAC
across pressure
switch N/O contact
& screw C on
board?
YES
Check/Replace:
1. Draft safeguard switch
2. Wire harness
Jumper across
screws R & W.
3. Flue choke
4. Inducer voltage
5. Inducer motor bearings
NO
Check/Replace:
1. Pilot
Is
inducer motor
on?
YES
Is
YES
YES
NO
Is
24VAC across gas
valve?
unit lit?
2. Thermocouple
3. Gas valve
NO
YES
Is
Is
Is
Replace
blower motor
and/or start
capacitor.
blower running
on heat speed 45
sec after unit
lights?
YES
NO
115VAC across
inducer motor
connector?
115VAC across
inducer motor
connector?
Replace
inducer motor.
NO
NO
YES
Is
Is
Is
24VAC
YES
NO
24VAC across
PL-2 & screw
C on board?
115VAC
across EAC-1
& COM?
NO
across
PL-1 & screw
C on board?
Replace
board.
Check/Repair
wire harness;
otherwise,
replace
NO
YES
YES
Check/Replace
thermostat
Replace
board.
Remove
R & M jumper.
Repair wire
harness.
and/or
pressure
thermostat wiring.
switch.
NO
After
NO
YES
off-delay
does blower
turn off?
Reconnect all
thermostat wires.
Does unit
operate?
NOTE: After replacing any component, verify correct operating
YES
sequence as indicated by bold arrows.
END OF TEST.
A91253
35005c
Copyright 1993 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book
Tab 6a 8a
1
4
PC 101
Catalog No. 565-801
Printed in U.S.A.
Form 58D,G-3SM
Pg 8
11-93
Replaces: 58D,G-2SM
Download from Www.Somanuals.com. All Manuals Search And Download.
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