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Service and Maintenance Instructions
For Sizes 040—120, Series 110
A93040
NOTE: Read the entire instruction manual before performing any
service or maintenance.
This symbol → indicates a change since the last issue.
Index Page
SAFETY CONSIDERATIONS..................................................1-2
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS........2
GENERAL......................................................................................2
CARE AND MAINTENANCE................................................2-10
Cleaning and/or Replacing Air Filter.......................................3
Blower Motor and Wheel Maintenance................................3-4
Cleaning Burners...................................................................4-5
Cleaning Heat Exchangers ....................................................5-6
Primary Heat Exchangers ................................................5-6
Secondary Heat Exchangers................................................6
Flushing Collector Box and Drainage System .....................6-7
Servicing Hot Surface Ignitor ...............................................7-8
Electrical Controls and Wiring.................................................8
Troubleshooting...................................................................8-10
Checking Heat Tape Operation (If Applicable) .................9-10
Winterizing..............................................................................10
WIRING DIAGRAM...................................................................12
SERVICE LABEL .......................................................................13
TROUBLESHOOTING GUIDE ............................................14-15
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.
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 (NFGC) NFPA
54-1996/ANSI Z223.1-1996 and the Installation Standards, Warm
58MSA
4-Way Multipoise Fixed-Capacity
Condensing Gas Furnace
®
ama
CANADIAN GAS ASSOCIATION
APPROVED
R
As an ENERGY STAR®
Partner, Carrier Corporation
has determined that this product meets the ENERGY
STAR® guidelines for energy
efficiency.
REGISTERED QUALITY SYSTEM
→ Fig. 1—Multipoise Furnace in Upflow Orienta-
Air Heating and Air Conditioning Systems (NFPA 90B)
ANSI/NFPA 90B. In Canada, refer to the CAN/CGA-B149.1- and
.2-M95 National Standard of Canada, Natural Gas and Propane
Installation Codes (NSCNGPIC). Wear safety glasses and work
gloves. Have a 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 unit and in instructions or
manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and 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 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. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
A98306
tion
.
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. 535-744 Printed in U.S.A. Form 58MSA-3SM Pg 1 5-99 Replaces: 58MSA-2SM
The ability to properly perform maintenance on this equipment requires certain expertise, mechanical skills, tools, and
equipment. If you do not possess these, do not attempt to
perform any maintenance on this equipment other than those
procedures recommended in the User’s Manual. FAILURE
TO FOLLOW THIS WARNING COULD RESULT IN
POSSIBLE DAMAGE TO THIS EQUIPMENT, SERIOUS
PERSONAL INJURY, OR DEATH.
Never store anything on, near, or in contact with the furnace,
such as:
1. Spray or aerosol cans, rags, brooms, dust mops, vacuum
cleaners, or other cleaning tools.
2. Soap powders, bleaches, waxes or other cleaning compounds, plastic or plastic containers, gasoline, kerosene,
cigarette lighter fluid, dry cleaning fluids, or other volatile
fluids.
3. Paint thinners and other painting compounds, paper bags,
or other paper products.
Failure to follow this warning can cause corrosion of the heat
exchanger, fire, personal injury, or death.
GENERAL
These instructions are written as if the furnace is installed in an
upflow application. An upflow furnace application is where the
blower is located below the combustion and controls section of the
furnace, and conditioned air is discharged upward. Therefore,
since this furnace can be installed in any of the 4 positions shown
in Fig. 2, you must revise your orientation to component location
accordingly.
AIRFLOW
UPFLOW
AIRFLOW
HORIZONTAL
LEFT
DOWNFLOW
HORIZONTAL
RIGHT
AIRFLOW
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
Electrostatic discharge can affect electronic components.
Take precautions during furnace installation and servicing to
protect the furnace electronic control. Precautions will prevent 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 CONTROL PRIOR TO DISCHARGING YOUR BODY’S ELECTROSTATIC 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
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.
AIRFLOW
A93041
Fig. 2—Multipoise Orientations
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equipment failure, it is essential that maintenance be performed annually
on this equipment. Consult your local dealer for maintenance and
maintenance contract availability.
Turn off the gas and electrical supplies to the unit before
performing any maintenance or service. Follow the operating
instructions on the label attached to the furnace. Failure to
follow this warning could result in personal injury or death.
The minimum maintenance that should be performed on this
equipment is as follows:
1. Check and clean or replace air filter each month as required.
2. Check blower motor and wheel for cleanliness annually.
3. Check electrical connections for tightness and controls for
proper operation each heating season. Service as necessary.
4. Check for proper condensate drainage. Clean as necessary.
5. Check for blockages in combustion-air and vent pipes annually.
6. Check burners for cleanliness annually.
Personal injury could result from sharp metal edges, etc. Use
care when removing parts.
2
WASHABLE
FILTER
WASHABLE
FILTER
FILTER
RETAINER
FILTER
SUPPORT
FILTER
RETAINER
A93046
Fig. 3—Bottom Filter Arrangement
Step 1—Cleaning and/or Replacing Air Filter
The air filter arrangement may vary depending on the application
or orientation.
Never operate unit without a filter or with the blower access
panel removed. Failure to follow this warning could result in
a fire or personal injury.
To clean or replace the filters, proceed as follows:
1. Turn off electrical supply to furnace.
2. Remove main furnace door and blower access panel.
3. Release filter retainer wire. (See Fig. 3 and 4.)
4. Slide filter out of furnace.
5. Furnaces are equipped with permanent, washable filter(s).
Clean filter by spraying cold tap water through filter in
opposite direction of airflow.
6. Rinse filter and let dry. Oiling or coating of filter is not
recommended.
7. Place filter in furnace.
8. Replace blower access panel and main furnace door.
9. Turn on electrical supply to furnace.
NOTE: If the filter has cross-mesh binding, the binding must face
the blower. If the filter has an air direction arrow, the arrow must
point toward the blower.
Step 2—Blower Motor and Wheel Maintenance
To ensure long life, economy, and high efficiency, clean accumulated dirt and grease from blower wheel and motor annually.
The inducer and blower motors are pre-lubricated and require no
additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
The following items should be performed by a qualified service
technician.
Clean blower motor and wheel as follows:
1. Turn off electrical supply to furnace.
2. Remove main furnace door and blower access panel.
3. Disconnect wires.
A93045
Fig. 4—Filter Installed for Side Inlet
All factory wires can be left connected, but field thermostat
connections may need to be disconnected depending on their
length and routing.
4. Position control box, transformer, and door switch assembly to
right side of furnace casing.
5. If condensate trap is located in left- or right-hand side of
furnace casing, proceed to item 6, otherwise remove trap and
tubing as described below.
a. Disconnect field drain connection from condensate trap.
b. Disconnect drain and relief port tubes from condensate
trap.
c. Remove condensate trap from blower shelf.
6. Remove screws securing blower assembly to blower shelf and
slide blower assembly out of furnace.
7. Clean blower wheel and motor by using a vacuum with soft
brush attachment. Be careful not to disturb balance weights
(clips) on blower wheel vanes. Do not bend wheel or blades as
balance will be affected.
8. If greasy residue is present on blower wheel, remove wheel
from the blower housing and wash it with an appropriate
degreaser. To remove wheel:
a. Mark blower wheel location on shaft before disassembly to
ensure proper reassembly.
b. Loosen setscrew holding blower wheel on motor shaft.
NOTE: Mark blower mounting arms and blower housing so each
arm is positioned at the same hole location during reassembly.
c. Mark blower wheel orientation and cutoff plate location to
ensure proper reassembly.
d. Remove screws securing cutoff plate and remove cutoff
plate from housing.
e. Remove bolts holding motor mounts to blower housing and
slide motor and mounts out of housing. Disconnect capacitor and ground wire attached to blower housing before
removing motor.
f. Remove blower wheel from housing.
g. Clean wheel per instructions on degreaser cleaner.
9. Reassemble motor and blower wheel by reversing items 8b
through 8f. Ensure wheel is positioned for proper rotation. Be
sure to reattach ground wire.
10. Reinstall blower assembly in furnace.
3
11. Reinstall condensate trap and tubing if previously removed.
a. Reinstall condensate trap in hole in blower shelf.
b. Connect condensate trap drain tubes. See Fig. 8 or tubing
diagram on main furnace door for proper tube location.
(1.) Connect 1 tube (blue or blue and white striped) from
collector box.
(2.) Connect 1 tube (violet or unmarked) from inducer
housing.
(3.) Connect 1 tube (relief port, green or pink) from
collector box.
c. Connect field drain to condensate trap.
NOTE: Ensure tubes are not kinked or pinched, as this will affect
operation.
12. Reinstall control box, transformer, and door switch assembly
on blower shelf.
13. Reconnect wires.
Refer to furnace wiring diagram, and connect thermostat leads
if previously disconnected. (See Fig. 15.)
NOTE: Refer to Table 1 for motor speed lead relocation if leads
were not identified before disconnection.
Table 1—Speed Selector
COLOR SPEED
Black High Cool
Yellow (When Present) Medium High Spare
Blue Medium Low Heat
Red Low Spare
White Common Com
Heating speed selection MUST be adjusted to provide proper
temperature rise as specified on the rating plate. Failure to
adjust the heating speed may shorten heat exchanger life.
14. Turn on electrical supply. Manually close blower access panel
door switch. Use a piece of tape to hold switch closed. Check
for proper rotation and speed changes between heating and
cooling by jumpering R to G and R to Y on control center
thermostat terminals. (See Fig. 11.)
Blower access panel door switch opens 115-v power to
control center. No component operation can occur. Caution
must be taken when manually closing this switch for service
purposes. Failure to follow this warning could result in
electrical shock, personal injury, or death.
15. If furnace is operating properly, release blower access panel
door switch, replace blower access panel, and replace main
furnace door.
Step 3—Cleaning Burners
The following items should be performed by a qualified service
technician. If the burners develop an accumulation of light dirt or
dust, they may be cleaned by using the following procedure:
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Remove burner box cover.
4. Using backup wrench, disconnect gas supply pipe from gas
valve.
FACTORY
ATTACHED TO
5. Remove wires from gas valve. Note location for reassembly.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous
operation.
6. Remove burner box pressure tube from gas valve regulator
fitting.
7. Remove screws that secure manifold to burner box. (See Fig.
5.)
MANIFOLD
MOUNTING
SCREW
MANIFOLD
GAS VALVE
REGULATOR
FITTING
GAS VALVE
A93295
Fig. 5—Burner Box Assembly
8. Remove manifold, orifices, and gas valve as 1 assembly.
9. Remove screws attaching burner assembly in burner box.
10. Remove burner assembly from burner box.
NOTE: All burners are attached to burner bracket and can be
removed as 1 assembly.
11. Clean burners with soft brush and vacuum.
12. Reinstall manifold, orifice, and gas valve assembly in burner
box. Ensure manifold seal grommet is installed properly and
burners fit over orifices.
13. Reconnect wires to gas valve. Refer to furnace wiring diagram
for proper wire location.
14. Reinstall burner box pressure tube to gas valve regulator
fitting.
15. Reinstall gas supply pipe to gas valve using backup wrench on
gas valve to prevent rotation and improper orientation.
NOTE: Use propane gas resistant pipe dope to prevent gas leaks.
DO NOT use Teflon tape.
Gas valve switch or knob MUST be facing forward or tilted
upward. Failure to follow this warning could result in
property damage, personal injury, or death.
16. Replace burner box cover.
17. Turn on gas and electrical supplies to furnace.
18. Check for gas leaks.
4
Never use matches, candles, flame, or other sources of
ignition to check for gas leakage. Use a soap-and-water
solution. Failure to follow this warning could result in a fire,
personal injury, or death.
19. Replace main furnace door.
Step 4—Cleaning Heat Exchangers
The following items should be performed by a qualified service
technician.
PRIMARY HEAT EXCHANGERS
If the heat exchangers get an accumulation of light dirt or dust on
the inside, they may be cleaned by the following procedure:
NOTE: If the heat exchangers get a heavy accumulation of soot
and carbon, both the primary and secondary heat exchangers
should be replaced rather than trying to clean them thoroughly due
to their intricate design. A build-up of soot and carbon indicates
that a problem exists which needs to be corrected, such as
improper adjustment of manifold pressure, insufficient or poor
quality combustion air, improper vent termination, incorrect size
or damaged manifold orifice(s), improper gas, or a restricted heat
exchanger (primary or secondary). Action must be taken to correct
the problem.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect wires or connectors to rollout switch, gas valve,
ignitor, and flame sensor.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous
operation.
PRIMARY HX
INLET OPENINGS
Fig. 6—Cleaning Inlet Openings of Primary Heat
Exchangers
→
NOTE: Inspect combustion-air intake housing. If foamed gasket
was removed, check for any damage. If gasket is damaged in any
way, it must be repaired. To repair, remove damaged gasket
section, apply sealant releasing agent such as PAM cooking spray
or equivalent (must not contain corn or canola oil, aromatic or
halogenated hydrocarbons or inadequate seal may occur) to burner
box and apply a small bead of G.E. RTV 162, G.E. RTV 6702, or
Dow-Corning RTV 738 sealant to edge of combustion-air intake
housing. (See Fig. 7.)
A93080
4. Disconnect combustion-air intake pipe from intake housing.
5. Remove the pressure switch tube from intake housing.
6. Remove screws attaching intake housing to burner box, and
rotate intake housing away from burner box for removal.
7. Using backup wrench, disconnect gas supply pipe from gas
valve.
8. Disconnect pressure tubing from gas valve.
9. Remove 2 screws attaching top filler panel and rotate upwards
to gain access to screws attaching burner box to cell panel.
10. Remove screws attaching burner box to cell panel. (See Fig.
5.)
NOTE: Burner box cover, manifold, gas valve, and burner
assembly should be removed as 1 assembly.
11. Clean heat exchanger openings with a vacuum and a soft
brush. (See Fig. 6.)
NOTE: After cleaning, inspect the heat exchangers to ensure they
are free of all foreign objects that may restrict flow of combustion
products.
12. Reverse items 4 through 10 for reassembly.
The ground wire from the gas valve MUST be attached to the
burner box attachment screw. Failure to attach this ground
wire to an adequate casing ground will cause the furnace
control to lock out.
NOTE: Be sure burner box gasket is installed between burner box
and cell panel. If gasket is damaged, replace it.
RTV
PAM
A93087
Fig. 7—Combustion-Air Intake Housing Gasket
Repair
13. Refer to furnace wiring diagram and connect wires to rollout
switch, gas valve, ignitor, and flame sensor.
14. Reconnect pressure switch tubes to gas valve and intake
housing. Refer to tube routing label on main furnace door for
proper tube location. Be sure tubes are not kinked. (See Fig.
8.)
15. Turn on gas and electrical supplies to furnace.
16. Check furnace operation through 2 complete heat operating
cycles. Look through sight glass in burner enclosure to check
burners. Burner flames should be clear blue, almost transparent. (See Fig. 9.)
17. Check for gas leaks.
5
Furnace is shipped from factory in upflow configuration. Pressure tube and drain tube routing MUST match the diagrams below.
Condensate Trap; Factory Installed
in Blower Shelf
(Blower access panel removed)
COLLECTO R BO X TU BE
(PINK)
COLLECTOR BOX TUBE
INDUCER HOUSING (MOLDE D) DRAIN TUBE
(BEHIND COLLECTOR BO X DRAIN T UBE)
FIELD-INSTALLED FACTORY-SUPPLIED
Condensate Trap on
BURNER ENCLOSURE PRES SURE
REFERENCE TUBE ASSEMBLY
INDUCER HOUSING DRAIN TUBE (VIOLET)
(GREEN)
COLLECTOR BOX DRAIN TUBE
(BLUE)
FIELD-INSTALLED
FACTORY-SUPPLIED DRAIN TUBE
COUPLING (LEFT DRAIN OPTION)
DRAIN TUBE
LEFT Side
COLLECTO R BO X
TUBE (GREEN)
COLLECTOR BOX DRAIN TUBE
(BLUE & WHITE STRIPE D)
COLL ECTOR BOX
EXTENSI ON TUBE
CONDENSATE TRAP
CAP
T ube location when used on
HORIZONTAL - LEFT ap plication
AUXILIARY "J" BOX RE LOCATED HERE
BURNER ENCLOSURE
PRESSURE REFE RENCE
TUBE ASSEMBLY
COLLECTOR BOX EXTENSION DRAIN TUBE
PLUG
CAP
COLLECTOR BOX
EXTENSIO N TUBE
CONDENSATE TRAP
NOTE:
1. All tubing must be connected securely and routed to avoid kinks and traps.
2. Pressure tubing must always slope away from pressure switch to collector box connection as shown.
3. HORIZONTAL-LEFT installations require the collector box pressure tube to be relocated between the inducer housing and the blower shelf to
prevent a trap.Refer to the Installation Instructions for further details.
T ube location when used in UPFLOW application
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
CAP
PLUG
COLLECTOR BOX DRAIN
TUBE
(BLUE & WHITE STRIPED )
CONDENSATE TRAP
FIELD-INSTALLED
FACTORY-SU PPL IE D
DRAIN TUBE COUPLING
(RIGHT DRAIN OPTION)
FIELD-INSTALLED
FACTORY-SUPPLIED 1/2-IN.
CPVC STREET ELBOWS (2)
FOR LEFT DRAIN OPTION
COLLECTOR BOX TUBE
(PINK)
COLLECTOR BO X TUBE (GR EEN )
COLLECTOR BOX DRAIN TUB E
(BLUE)
CONDENSATE TRAP
T ube location when used in DOWNFLOW app lication
COLL ECTOR BOX
DRAIN TUBE (BLUE)
COLLECTOR BOX DRAIN TUBE
DRAIN TUBE
COUPLING
PLUGGED END
PLUG
COLLECTOR BOX
EXTENSIO N TUBE
COLL ECTOR BOX
TUBE ( PINK)
(BLUE & WHITE STRIPED )
COLLECTOR BOX
TUBE (GREEN)
INDUCER HOUSING
DRAIN TUBE
(VIOLET)
COLLECTOR BOX
DRAIN TUBE ( BLUE)
COLLECTOR BOX TUBE (PINK)
RELOCATE TUBE BET W EEN BLOWER
SHELF AND INDUCER HOU SING FOR
040,060, AN D 080 HEATIN G IN PUT
FURNACES
COLLECTO R BO X D R AIN
TUBE
(BLUE & WHITE STRIPED)
INDUCER HOUSING DRAIN
TUBE (VIOLET)
DRAIN TUBE COUPLING
DRAIN TUBES ROUT ED IN
FRONT OF GAS VALVE
COLLECTOR BOX DRAIN TUB E
(BLUE)
PLUG
CAP
COLLECTOR BOX
TUBE (GREEN)
COLLECTOR BOX DRAIN TUBE
(BLUE AND WHITE STRIPED)
T ube location when used on
HORIZONTAL - RIGHT appli cation
→ Fig. 8—Furnace Pressure and Drain Tubing Diagram
TUBE ROUTING
Condensate Trap on LEFT
Side Optional
BURNER ENCLOSURE
PRES SURE REFERENCE
TUBE ASSEMBL Y
CAP
PLUG
COLLECTOR BOX DRAIN TUBE
(BLUE & WHITE STRIPED )
INDUCER HOUSING DRAIN TUBE
Condensate Trap on
PLUG
CAP
COLLECTOR BOX DRAIN TUB E
(BLUE)
COLL ECTOR BOX TUBE
(PINK)
COLLECTO R BO X TU BE
(GREEN)
COLLECTO R BO X EXT ENSION TUBE
BURNER ENCLOSURE PRES SURE
REFERENCE TUBE ASSEMBLY
CONDENSATE TRAP
COLLECTO R BO X
GAS VALVE
INDUCER HOUSING DRAIN TUBE (VIOLET)
EXTENSION DRAIN TUBE
COLLECTOR BOX EXTENSION TUBE
COLLECTOR BOX TUBE (PINK)
BURNER ENCLOSURE
PRESSURE REF ERENCE
TUBE ASSEMBL Y
COLLECTO R BO X
EXTENSIO N TUBE
CONDENSATE TRAP
324999-201 REV. A
(LIT. BOTTOM)
(VIOLET)
RIGHT Side
A99102
BURNER FLAME
MANIFOLD
Fig. 9—Burner Flame
BURNER
A89020
Never use matches, candles, flame, or other sources of
ignition to check for gas leakage. Use a soap-and-water
solution. Failure to follow this warning could result in a fire,
personal injury, or death.
18. Replace main furnace door.
SECONDARY HEAT EXCHANGERS
NOTE: The condensing side (inside) of the secondary heat
exchangers CANNOT be serviced or inspected. A small number of
bottom outlet openings can be inspected by removing the inducer
assembly. See Flushing Collector Box and Drainage System
section for details on removing inducer assembly.
Step 5—Flushing Collector Box and Drainage
System
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect inducer motor and pressure switch wires or
connectors.
6
4. Disconnect pressure switch tubes.
5. Disconnect vent pipe from inducer housing outlet by loosening coupling clamp on inducer outlet.
6. Disconnect drain tube from inducer housing. (See Fig. 8.)
7. Remove inducer housing assembly by removing 4 bolts
attaching assembly to cell panel.
8. Flush inside of collector box with water until discharge from
condensate trap is clean and runs freely.
NOTE: Ensure the drain tube disconnected from the inducer
housing is higher than the collector box opening or water will flow
out tube.
9. Inspect inside area of collector box for any pieces of foreign
materials and remove if present.
DO NOT use wire brush or other sharp object to inspect or
dislodge materials in secondary heat exchangers as failure of
the secondary heat exchanger will occur. Flush with water
only.
10. Reassemble inducer assembly by reversing items 5 through 7.
→
Tighten the vent coupling clamp screw(s) to 15 in.- lb. of
torque.
NOTE: If seal between the inducer housing and the collector box
→
is damaged in any way, it must be repaired. To repair, apply
sealant releasing agent such as PAM cooking spray or equivalent
(must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) to inducer housing.
(See Fig. 10.) Apply a small bead of G.E. RTV 162, G.E. RTV
6702, or Dow-Corning RTV 738 sealant to groove in collector
box.
14. Check furnace operation through 2 complete heat operating
cycles. Check area below inducer housing, vent pipe, and
condensate trap to ensure no condensate leaks occur. If leaks
are found, correct the problem.
15. Check for gas leaks.
Never use matches, candles, flame, or other sources of
ignition to check for gas leakage. Use a soap-and-water
solution. Failure to follow this warning could result in a fire,
personal injury, or death.
16. Replace main furnace door.
Step 6—Servicing Hot Surface Ignitor
The ignitor does NOT require annual inspection. Check ignitor
resistance before removal.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect ignitor wire connection.
4. Check ignitor resistance.
a. Using an ohm meter, check resistance across both ignitor
leads in connector.
b. Cold reading should be between 45 ohms and 90 ohms.
c. If ohm reading is higher than 110 ohms, ignitor is cracked
and must be replaced.
5. Remove ignitor assembly.
Allow ignitor to cool before removal. Normal operation
temperatures exceed 2000°F.
PAM
RTV
A93081
Fig. 10—Gasket on Collector Box
11. Refer to furnace wiring diagram and connect wires to inducer
motor and pressure switch or connectors.
12. Reconnect pressure tubes to pressure switch. See diagram on
main furnace door for proper location of tubes. Be sure tubes
are not kinked. (See Fig. 8.)
13. Turn on gas and electrical supplies to furnace.
→
a. Do not remove ignitor from bracket while assembly is in
furnace. Using a 1/4 in. nutdriver, remove screw securing
bracket and ignitor assembly to bottom of burner box. The
screw in the bracket is always located toward outside of
burner box. The screw may be hidden by inlet box or inlet
pipe, but can be removed without removing either. After
removing screw, slide ignitor and bracket toward outside of
burner box and pull straight out.
The ignitor is fragile. DO NOT allow it to hit the side of the
burner box opening while removing or replacing it.
b. Inspect ignitor for a white area indicating a crack may be
present. If found, replace ignitor.
NOTE: A small crack cannot be seen on a new ignitor. After a
period of operation, a white area will be visible around the crack.
c. If replacement is required, replace ignitor on ignitor
→
bracket external to furnace to avoid damage as the silicon
portion is very brittle and will easily crack or shatter.
d. To remove ignitor from ignitor bracket, remove screw
→
holding ignitor ceramic block to bracket and pull ceramic
block out of bracket.
6. To replace ignitor/ignitor assembly, reverse items 5a through
→
5d.
7. Reconnect ignitor wire connection.
8. Turn on gas and electrical supplies to furnace.
9. Verify ignitor operation by initiating control board self-test
→
feature or by cycling thermostat.
7
10. Replace main furnace door.
Step 7—Electrical Controls and Wiring
There may be more than 1 electrical supply to the unit. Check
accessories and cooling unit for additional electrical supplies.
The electrical ground and polarity for 115-v wiring must be
maintained properly. Refer to Fig. 11 for field wiring information
and to Fig. 15 for unit wiring information.
NOTE: If the polarity is not correct, the STATUS LED on the
control center will flash rapidly and prevent the furnace from
operating. The control system also requires an earth ground for
proper operation of the control center and flame sensing.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control center. (See Fig. 12.) Any direct shorts of the 24-v
wiring during installation, service, or maintenance will cause this
fuse to blow. If fuse replacement is required, use ONLY a fuse of
identical size.
With power to the unit disconnected, check all electrical connections for tightness. Tighten all screws on electrical connections. If
any smoky or burned connections are found, disassemble the
connection, clean all parts, strip wire, and reassemble properly and
securely.
Reconnect electrical supply to unit and observe unit through 1
complete operating cycle. Electrical controls are difficult to check
without proper instrumentation; if there are any discrepancies in
the operating cycle, contact your dealer and request service.
Step 8—Troubleshooting
For an explanation of fault codes, refer to service label located on
back of main furnace door or Fig. 16, and the Troubleshooting
Guide.
The control center stores 1 fault code (the last fault to occur) for a
period of 48 hrs or until the 115- or 24-v power is interrupted.
NOTE: Removing blower access panel will open blower access
panel door switch and terminate 115-v power to control center, and
fault code will be erased. Look into blower access panel sight glass
for current LED status.
The unit’s component test is a useful troubleshooting tool since it
displays the current status (fault code) of the furnace and functionally operates all furnace components except the gas valve. The
component test and methods to initiate it are described below.
COMPONENT TEST SEQUENCE
NOTE: All components are functionally operated except the gas
valve.
When component test is initiated, the following sequence of events
occurs:
1. LED flashes a fault code 4 times.
2. Inducer motor starts and continues to run for remainder of
component test.
3. Hot surface ignitor is energized for 15 sec, then de-energized.
4. Main blower operates at cooling speed for 10 sec, then turns
off.
5. Main blower operates at heating speed for 10 sec, then turns
off.
6. Inducer motor stops.
Component test can be initiated by one of the following procedures.
INITIATING COMPONENT TEST AND RETRIEVING STA-
→
TUS CODE BY REMOVING MAIN LIMIT SWITCH WIRE
NOTE: NO thermostat signal may be present at control center
and all blower time delay off periods must be completed.
1. Leave 115-v power to furnace turned on.
2. Remove main furnace door.
3. Look into blower access panel sight glass for current LED
status.
NOTE: Leave blower access panel installed to maintain power to
control center to view current LED status.
BLK
WHT
115-V
FIELD-SUPPLIED
DISCONNECT
WHT
GND
THREE-WIRE
BLK
AUXILIARY
J-BOX
FIVE
WIRE
HEATING-
ONLY
GND
CONTROL
BOX
FURNACE
NOTE 2
W
R
G
C
Y
24-V
TERMINAL
BLOCK
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
WCR GY
NOTE 1
NOTES: Connect Y-terminal as shown for proper operation.
1.
2.
3.
THERMOSTAT
TERMINALS
CONDENSING
UNIT
TWO
WIRE
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.
FIELD-SUPPLIED
DISCONNECT
GND
→ Fig. 11—Field Wiring
8
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
A98209
GRYW
24-V THERMOSTAT
TERMINALS
TEST/TWIN
SEC-1
3-AMP FUSE
COOL
HEAT
115-VAC (L1)
POWER SUPPLY
HOT SURFACE
IGNITOR CONNECTOR
Fig. 12—Control Center
4. BRIEFLY remove either wire from the main limit switch until
the LED goes out, then reconnect it.
Make sure limit switch wire does not contact any metallic
component such as the gas valve. If wire is shorted, 3-amp
fuse on control center will blow.
NOTE: If wire to main limit is disconnected longer than 4 sec, the
control senses limit circuit is open. Main blower will start and
retrieval request will be ignored.
5. When above items have been completed, the component test
sequence will occur as described in the Component Test
Sequence section above.
NOTE: Be sure to record the fault code which is flashed 4 times
at start of component test for further troubleshooting.
6. After component test is completed and LED is ON continuously indicating the furnace is ready to operate when a signal
from the thermostat is received, replace main furnace door.
INITIATING COMPONENT TEST AND RETRIEVING STA-
→
TUS CODE BY JUMPERING CONTROL TEST TERMINAL
1. Remove main furnace door.
2. Remove blower access panel.
3. Manually close blower access panel door switch. Use a piece
of tape to hold switch closed.
OM
24V
C
HUM
115-VAC (L2) NEUTRAL
CONNECTION
INDUCER MOTOR
CONNECTOR
NOTE: If TEST to C
LED will flash rapidly, and retrieval request will be ignored.
NOTE: Be sure to record the fault code which is flashed 4 times
at start of component test for further troubleshooting.
Step 9—Checking Heat Tape Operation (If Applicable)
In applications where the ambient temperature around the furnace
is 32°F or lower, freeze protection measures are required. If this
application is where heat tape has been applied, check to ensure it
will operate when low temperatures are present.
NOTE: Heat tape, when used, should be wrapped around the
condensate drain trap and drain line. There is no need to use heat
tape within the furnace casing. Most heat tapes are temperature
activated, and it is not practical to verify the actual heating of the
tape. Check the following:
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX)
LED OPERATION &
DIAGNOSTIC LIGHT
HARNESS CONNECTOR
24-V TRANSFORMER SEC-2
SPARE-1
BLOWER SPEED
SELECTION TERMINALS
SPARE-2
EAC-1
EAC-ELECTRONIC AIR CLEANER
TERMINALS (115-VAC 1.5 AMP MAX)
EAC-2
A95086
Blower access panel door switch opens 115-v power to
control center. No component operation can occur. Caution
must be taken when manually closing this switch for service
purposes. Failure to follow this warning could result in
electrical shock, personal injury, or death.
4. BRIEFLY short (jumper) TEST, 1/4-in. quick-connect terminal on control center (adjacent to the LED diagnostic light)
and the C
OM terminal on thermostat connection block. (See
Fig. 12.)
OM terminals are jumpered longer than 2 sec,
5. When above items have been completed, the component test
sequence will occur as described in the Component Test
Sequence section above.
6. After component test is completed and furnace is operating
properly, release blower access panel door switch, replace
blower access panel, and replace main furnace door.
9
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
A93058
If this furnace is installed in an unconditioned space where
the ambient temperatures may be 32°F or lower, freeze
protection measures must be taken.
1. Check for signs of physical damage to heat tape such as nicks,
cuts, abrasions, gnawing by animals, etc.
2. Check for discolored heat tape insulation. If any damage or
discolored insulation is evident, replace heat tape.
3. Check that heat tape power supply circuit is on.
Step 10—Winterizing
Freezing condensate left in the furnace will damage the
equipment.
If the furnace will be off for an extended period of time in a
structure where the temperature will drop to 32°F or below,
winterize as follows:
1. Turn off electrical supply to furnace.
2. Remove main furnace door.
3. Disconnect drain tube from inducer housing. (See Fig. 13.)
4. Insert funnel in drain tube and pour antifreeze, propylene
glycol (RV, swimming pool antifreeze, or equivalent) into
furnace until it is visible at point where condensate enters open
drain. (See Fig. 14.)
5. Reconnect drain tube to inducer housing.
6. Replace main furnace door.
Do not use ethylene glycol (Prestone II antifreeze/coolant or
equivalent automotive type). Failure of plastic components
will occur.
10
→ Fig. 13—Inducer Housing Drain Tube
A99118
A99119
→ Fig. 14—Funnel in Drain and Antifreeze Running
Through Trap
11
SW2
PCB
SEE NOTE #10
(NO T O N AL L MODELS)
BLOWER OFF DELAY
SELECTION CHART
90 SEC
BLOWER
OFF
DELAY
TEST/TWIN
SW1
HUM
G
R
Y
W
C
LED
ORN
OM
135 SEC
PL1
WHT
BLOWER
SPEED
SELECT
L2
PR2
WHT
WHT
GRN
BLK
SEC-1
FU1
BRN
321
6
9
24 VAC-3A
FUSE
COOL
HEAT
EAC-1
EAC-2
CAP -2
M
4
5
87
SEC-2
SPARE-1
SPARE-2
C
OM
AUX
OL
1.5 AMP
BRN
IDM
180 SEC
225 SEC
GVR
HSIR IDR BLWR
PL2
VAC
120
L1
BLK
PR1
BLK
BLK
12
HSI
1
2
BLK
1
WHT
PL5
PL3
23
HI/LO
RELAY
1
2
3
WHT
GRN
PL4
LEGEND
BLWR BLOWER MOTOR RELAY, SPST-(N.O.)
BLWM BLOWER MOTOR
CAP CAPACITOR
CPU MICROPROCESSOR AND CIRCUITRY
EAC-1 ELECTRONIC AIR CLEANER CONNECTION (115 VAC 1.5 AMP MAX.)
EAC-2 ELECTRONIC AIR CLEANER CONNECTION (COMMON)
FRS FLAME ROLLOUT SW. -MANUAL RESET, SPST-(N.C.)
FSE FLAME PROVING ELECTRODE
FU1 FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED
FU2 FUSE OR CIRCUIT BREAKER CURRENT INTERRUPT DEVICE
(FIELD INSTALLED & SUPPLIED)
GND EQUIPMENT GROUND
GV GAS VALVE-REDUNDANT OPERATORS
GVR GAS VALVE RELAY, DPST-(N.O.)
HI/LO BLOWER MOTO R SPEED CHANGE RELAY, SPDT
HSI HOT SURFACE IGNITOR (115 VAC)
HSIR HOT SURFACE IGNITOR RELAY, SPST-(N.O.)
HUM 24VAC HUMIDIFIER CONNECTION (.5 AMP. MAX.)
IDM INDUCED DRAFT MOTOR
IDR INDUCED DRAFT RELAY, SPST-(N.O.)
ILK BLOWER ACCESS PANEL INTERLOCK SWITCH, SPST-(N.O.)
JB JUNCTION BOX
LED LIGHT-EMITTING DIODE FOR STATUS CODES
LGPS LOW GAS PRESSURE SWITCH, SPST-(N.O.)
LS LIMIT SWITCH, AUTO RESET, SPST(N.C.)
OL AUTO-RESET INTERNAL MOTOR OVERLOAD TEMP. SW.
PCB PRINTED CIRCUIT BOARD
RED
WHT
BLK (HI)
YEL (MED HI)
NOTE #8
BLU (MED LO)
RED (LO)
WHT (COM)
(WHEN USED)
PRS
RED
LS
BLU
RED
OL
WHT
BLK
ILK
PL1 9-CIRCUIT CONNECTOR
PL2 2-CIRCUIT PCB CONNECTOR
PL3 3-CIRCUIT IDM CONNECTOR
PL4 3-CIRCUIT IDM EXTENSION CONNECTOR
PL5 2-CIRCUIT HSI/PCB CONNECTOR
PRS PRESSURE SWITCH, SPST-(N.O.)
SW1 & 2 BLOWER OFF DELAY
TEST/TWIN COMPONENT TEST & TWIN TERMINAL
TRAN TRANSFORMER-115VAC/24VAC
LGPS
NOTE #6
BLU
FRS
FSE
RED
GRN
BLK
WHT
TRAN
WHT (COM)
BRN
START
BLWM
JB
GRN
GND
JUNCTION
UNMARKED TERMINAL
PCB TERMINAL
FACTORY WIRING (115VAC)
FACTORY WIRING (24VAC)
FIELD WIRING (115VAC)
FIELD WIRING (24VAC)
CONDUCTOR ON PCB
FIELD WIRING TERMINAL
FIELD EARTH GROUND
EQUIPMENT GROUND
FIELD SPLICE
PLUG RECEPTACLE
CAP -1
BRN
FUSED DISCONNECT
SWITCH (WHEN REQ'D)
WHT
BLK
GRN
1-M
GRN
NOTE #4
FU2
YEL
3-P
GV
2-C
NOTE #5
NEUTRAL
L1
TO 115VAC FIELD DISCON NECT
NOTE #4
NOTE #12
L1
ILK
L1
TEST/TWIN
HUM
R
W
Y
G
C
OM
NEUTRAL
BLWR
HSIR
IDR
FU1
NOTE #7
HSIR
GND
IDR
HI/LO
EAC-1
EAC-2
PR1
TRAN
SEC-1
GVR-2
BLWR
CPU
EQUIPMENT GROUND
SPARE-2
HEAT
SPARE-1
NOTE #8
COOL
COM
1
PL2
115VAC
24VAC
SEC-2
HI/LO
GVR
GVR-1
NOTES:
1. IF ANY OF THE ORIGINAL EQUIPMENT WIRE IS REPLACED USE WIRE RATED FOR 105˚C.
2. INDUCER (IDM) AND BLOWER (BLWM) MOTORS CONTAIN INTERNAL
AUTO-RESET THERMAL OVERLOAD SWITCHES (OL).
3. BLO W ER MOTO R SPEED SE LEC T IO N S ARE FOR AVERAGE C ONDITIONS, SE E INSTALLATION
INSTRUCTIONS FOR DETAILS ON OPTIMUM SPEED SELECTION.
4. USE ONLY COPPER W IRE BETWEEN THE DISCONNEC T SWITCH AND THE
FURNACE JUNCTION BOX (JB).
5. THIS WIRE MUST BE CONNECTED TO FURNACE SHE ETMETAL FO R CO NTRO L TO PRO V E
FLAME.
6. FACTORY CONNECTED WH EN LGPS NOT USED.
7. REPL ACE ONLY WITH A 3 AM P FUSE.
8. YELLOW LEAD NOT ON ALL MOTO RS.
9. BLOWER-ON DELAY, GAS HEATING 60 SECONDS, COOLING OR HEAT PUMP 2 SECO NDS .
10. BLOWER-OFF DELAY, GAS HEATING 90, 135, 180 OR 2 25 SECONDS , COOLING OR
HEAT PUMP 90 SECONDS. (135 SECONDS ONLY ON SOME M ODELS)
11. IGNITION-LOCKOUT WILL OCCUR AFTER FOUR CONSECUTIVE UNSUCCESSFUL
TRIALS-FOR-IGNITION. CONTROL WILL AUTO-RESET AFTER THREE HOURS.
12. SOME MODELS MAY HAVE SPADE QUICK CONNECT TERMINALS.
SCHEMA TIC DIAGRAM
(NATURAL GAS & PROPAN E)
LO
MED LO
MED HI
HI
OL
COM
1
HSI
2
PL52
1
PR2
1
3
3
PL3
2
2
FRS
7
1
LGPS
4
PL1
PRS
3
3-P
2
1-M
8
5
6
9
322854-101 R EV . D (LIT)
BRN
PL4
NOTE #6
START
M
CAP -2
A99106
CAP-1
BLWM
IDM
OL
AUX
BRN
(WHEN USED)
GV
2-C
NOTE #5
FSE
LS
L2
→ Fig. 15—Wiring Diagram
12
SERVICE
If status code recall is needed, do not remove pow er or b lower door. Briefly remove and then
reconnect one main limit wire to display stored status code.
LED CODE
CONTINUOUS OFF - Check for 115VAC at L1 and L2, and 24VAC at SEC-1 and
CONTINUOUS ON - Control has 24V power.
RAPID FLASHING - Line vo ltage (11 5V ) polarity revers ed. If twinned, refer to
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST
DIGIT DETERMINED BY THE NUMB ER OF SHORT FLASHES AND THE S ECO N D D IGIT BY
THE NUMB ER O F LO NG F LASHES .
11 NO PREVIOU S CODE - Sto red status c od es are erased when po w er
(115V or 24V) to control is interrupted or 48 hours after each fault is cleared.
12 BLOW ER ON A FTER POWER UP (115V or 24V) - Blow e r runs for 90 seconds,
if unit is powere d u p during a call for heat (R-W closed).
13 LIMIT OR FLAME ROLL-OUT SWITCH LOCK OUT - Contr o l will a u to res et after
three hours unless flame roll- out switch or fuse link is opened , r efer to #33.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING L OCKOUT - C ontrol will NOT auto re set.
Chec k for:- M is-wired ga s valve -Defec t ive control (valve relay)
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved w hile gas valve is
de-energized. Inducer will run until fault is cleared.
Check for: - Leaky gas valve -Stuck-open gas valve
23 PRESSURE SW ITC H (ES) DID NO T OPE N Check for:
- Obstructed pressure tubing. - Defective pressure switch (stuck closed).
24 SECONDARY VOLTAGE FUSE IS OPEN
Check for:- S hor t circuit in seco ndary voltage (24V) wiring.
31 PRESSURE, DRAFT SAFEGUARD, AUXILIARY-LIMIT (when used), OR BLOCKED
VENT SHUTOFF (when used) SWITCH DID NOT CLOSE OR REOPENED - If open
longer than five minutes , inducer shuts off for 15 minutes b efore retry.
Check for: - Inadequate Combustion air supply.
- Proper v ent sizing an d condensa t e pitch or sag
- Low inducer voltage.
- Vent restriction or high winds.
- Disconnect ed or obstruct ed pressure tubing
- Defec t ive inducer motor or star t capacitor.
- Defec t ive pressure switch or connections . If it opens after trial for ig nit io n
period , blower will co me on for 90 second recycle delay.
33 LIMIT OR FLAME ROLL-OUT SWITCH IS OPEN - If open longer than three
minutes, code changes to #13. Flame roll-out switch requires manual reset.
Check for: - Defective blower motor or capacitor.
- Dirty filter or restricted duct system.
- Loose blower wheel.
- Defective switch or connections.
- Inadequate Combustion air supply (F lame Roll-out Switch or fu se link).
- Open Fla me Roll-ou t switch,or fuse link. Manual reset o r r eplace.
34 IGNITIO N PROVING FAILURE - Control will try three more times before a
lockout #14 occurs. If flame signal lost after trial for ignition period, blower
will come on for 90 second recycle delay. Check for:
- Oxide buildup on flame sens or (clean with fine steel wool).
- Prope r fla me sense mi croamps (.5 microamp s D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off.
- Defective Hot Surface Ignitor
- Manual valve shut-off.
- Low inlet gas pressure.
- Green wire MUST be connected to furnace sheet metal.
- Inadequate flame carryov er or rough ignition.
SEC-2.
twinning k it instr u ct io ns .
COMPONENT TEST
To initia te the component test se quence,sh ut OFF the room thermost at o r
disconnect the "R" thermostat lead. Briefly short the TEST terminal to the "Com
24V" terminal. Status LED will flash code and then turn ON the inducer motor. The
inducer moto r will ru n f or the entire com p onent te s t. The ho t surface ignitor ,
blower motor-heat spe ed, and blower motor-cool speed will be turned ON for
10-15 seconds each. Gas Valve and Humidifier will not be turned on.
6
3
9
2
8
5
1
7
4
STATUS
TEST
HUM
STATUS
Com
W
24V
Y
R
320615-102 R EV . J
G
→ Fig. 16—Service Label
13
A99107
NO
Close circuit breaker and
go back to start.
Close door switch and go to start.Is red LED status light on? Is door switch closed?
NO
Is circuit breaker closed?
NO
YES
Is there 115v going to switch?
NO
NO
YES
YES
YES
Is 24 vac present at W, Y, or G
terminals on the control?
Replace control if it does not
respond to 24-vac signal at W, Y,
or G screw terminals.
Check for continuity in wire from circuit
breaker to furnace.
NO
Check room thermostat or
interconnecting cable.
NO
YES
Replace door switch.Replace control center.
Replace transformer.
Does control respond to W, Y,
or G 24-vac thermostat signals?
Run system through a heating or
cooling cycle to check operation.
Status codes are erased after 48
hrs or whenever power (115v
or 24v) is interrupted.
NO
Is there 115v at L1 and L2?
NO
→ Troubleshooting Guide
START
YES
YES
Is there 24v at SEC-1 and SEC-2?
YES
Check for correct line voltage
polarity. If units are twinned,
check for proper low-voltage
(24v) transformer phasing.
Check for previous fault by
momentarily shorting the TEST
terminal and the C terminal until
the LED goes out. LED will flash
YES
NO
NO
Is red LED status light blinking
ON/OFF slowly with a
combination of short and long
Is red LED status light blinking
rapidly without a pause?
flashes?
the status code of any previous
fault or the code No. 11 (1 short
and 1 long flash) if no previous
fault. After the control repeats the
code 3 times, the control will go
through a brief component test
sequence. The inducer will start
and run for the entire component
test. The HSI, blower motor heat
speed, and blower motor cool
speed will run for 10-15 sec each.
YES
Determine status code. The
status code is a 2 digit number
with the first digit determined by
the number of short flashes and
the second digit by the number of
long flashes.
14
YES
Was there a previous fault code
other than No. 11?
Go to section with status code
determined.
A99123
Replace control center.
NO
YES
Unplug ignitor harness from control
center and inititate another
component test sequence. Check
for 115v between pins 1 and 2 on
the control center. Was 115v present
for the 17-sec period?
Check for continuity in the harness
and ignitor. Replace defective
component.
Check connections. If OK, replace
control center.
NO
Reconnect the R thermostat lead
and set thermostat to call for heat.
Connect voltmeter across gas valve
connections. Does gas valve
Check that all gas valves are turned
on. Replace valve.
NO
YES
receive 24v?
YES
Does gas valve open and allow gas
to flow?
NO
rough ignition.
• Low inlet gas pressure.
• Inadequate flame carryover on
Check for:
NO
YES
Do main burners ignite?
Repeat call for heat and check flame
sensor current during trial for ignition
NO
YES
Do main burners stay on?
Allow blower to come on and repeat
test to check for intermittent
Check connections and retry. If
current is near typical value and
control will not stay on, replace
control center.
YES
period. Is the DC microamps
below 0.5?
operation.
Replace electrode.
NO
Clean flame sensor with fine
sandpaper and recheck current.
Current is nominally 4.0 to 6.0 microamps.
Is current near typical value?
Replace control center.
NO
YES
YES
Will main burner ignite and stay on?
Fixed.
NOT CLOSE OR REOPEN - If
open longer than 5 minutes,
31 PRESSURE SWITCH WILL
are erased after 48 hrs or
11 NO PREVIOUS FAULT - Faults
sag.
inducer shuts off for 15 minutes
before retry.
Check for:
• Proper vent sizing or pitch or
whenever power (115v or 24v) is
interrupted. Run system through
a heating or cooling cycle to
check system.
connections. If it opens after
trial for ignition period, blower
will come on for 90 sec
• Vent restrictions or high winds.
• Defective inducer motor.
• Low line voltage (115v).
• Motor start capacitor.
• Low inlet gas pressure.
• Defective pressure switch or
UP (115V OR 24V) - Normal
operation. Blower will run for 90
sec when furnace power is
12 BLOWER ON AFTER POWER
recycle delay.
interrupted during a call for heat,
R-W closed.
13 LIMIT OR FLAME ROLLOUT
• Inadequate combustion air.
SWITCH IS OPEN - If
limit switch is open longer than 3
minutes, code changes to No. 13.
Check for:
• Blower motor failure.
33 LIMIT OR FLAME ROLLOUT
SWITCH LOCKOUT -
Limit switch was open longer
than 3 minutes. Auto-reset will
occur after 3 hrs. Flame rollout
switch requires manual reset.
See No. 33
failed to ignite gas and prove
14 IGNITION LOCKOUT - System
manual reset.
Inadequate combustion air
• Motor start capacitor.
supply (flame rollout switch
• Open flame rollout switch,
•
flame in 4 attempts. Control will
auto-reset in 3 hrs.
See No. 34
connections.
only).
• Dirty filter.
• Defective limit switch or
• Loose blower wheel.
• Stuck closed gas valve relay
Turn off power and wait 5
minutes to retry.
Check for:
21 GAS HEATING LOCKOUT -
If flame is not sensed during the
trial for ignition period, the control
will repeat the ignition sequence
3 more times before going into
lockout, No. 14.
If flame signal is lost after trial for
34 IGNITION PROVING FAILURE -
wire.
on control.
• Miswire or short to gas valve
SIGNAL - Flame was sensed
while gas valve was
de-energized. Inducer will run
22 ABNORMAL FLAME PROVING
NO
ignition period, blower will come
on for 90-sec recycle delay.
Check for the following items first
before proceding to the next step.
or leak.
until fault is cleared.
Check for:
• Stuck open gas valve solenoid
to furnace sheet metal.
• Gas valve turned off.
• Manual shut-off valve.
• Green wire must be connected
To determine whether the
problem is in the gas valve,
ignitor, or flame sensor, the
• Defective control center.
pressure tubing.
NOT OPEN - Check for:
• Disconnected or obstructed
23 PRESSURE SWITCH WILL
system can be operated in the
component test mode to check
the ignitor. First, remove the
R thermostat connection from the
control center and initiate the
component test sequence. Does
the ignitor glow orange/white hot
by the end of the 17-sec warm-up
period?
including thermostat leads
shorting to ductwork or
furnace cabinet. Disconnect
• Defective pressure switch.
OPEN - Check for:
24 LOW-VOLTAGE FUSE IS
thermostat leads to isolate
• Short in low-voltage wiring
YES
short circuit.
15
SERVICE TRAINING
Packaged Service Training programs are an excellent way to increase your
knowledge of the equipment discussed in this manual, including:
• Unit Familiarization • Maintenance
• Installation Overview • Operating Sequence
A large selection of product, theory, and skills programs is available, using popular
video-based formats and materials. All include video and/or slides, plus companion
book.
Classroom Service Training plus "hands-on" the products in our labs can mean
increased confidence that really pays dividends in faster troubleshooting, fewer
callbacks. Course descriptions and schedules are in our catalog.
CALL FOR FREE CATALOG 1-800-962-9212
[ ] Packaged Service Training [ ] Classroom Service Training
A94328
Copyright 1999 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 58msa3sm
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. 535-744 Printed in U.S.A. Form 58MSA-3SM Pg 16 5-99 Replaces: 58MSA-2SM
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