Sequence Of Operation - Carrier 58SU0A Series Installation, Start-Up, Operating And Service And Maintenance Instructions

(9.) Reinstall the insulation assembly.
NOTE: If insulation assembly is damaged, do not attempt to
repair, must be replaced with insulation kit.
NOTE: Proper use of Personal Protective Equipment (PPE)
must be followed, including safety glasses, gloves, and dust mask
when removing and reinstalling the heat exchanger insulation
assembly.
(10.) Reinstall burner assembly.
10. Remove old sealant from cell panel and collector box
flange.
11. Spray releasing agent on the heat exchanger cell panel
where inducer cover assembly contacts cell panel.
NOTE: A releasing agent such as cooking spray or equivalent
(must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow- -Corning 738) are needed before
starting installation.
NOTE: DO NOT substitute any other type of RTV sealant.
12. Apply new sealant to flange of collector box and attach to
cell panel using existing screws, making sure all screws
are secure.
13. Reconnect wires to the following components. (Use
connection diagram on wiring label, if wires were not
marked for reconnection locations.):
a. Burner thermal switch
b. Inducer motor
c. Transducer
d. Limit over- -temperature switch
e. Gas valve
f. Hot surface igniter
g. Flame- -sensing electrode
14. Reinstall vent connector on furnace vent elbow. Securely
fasten vent connector to vent elbow with two (2)
field- -supplied, corrosion- -resistant, sheet metal screws
located 180_ apart.
15. Replace blower access door only, if it was removed.
16. Set thermostat above room temperature and check furnace
for proper operation.
17. Verify blower airflow and speed changes between heating
and cooling.
18. Check for gas leaks.
19. Replace outer access door.
Representative drawing only, some models may vary in appearance.
Fig. 37 - - Cleaning Heat Exchanger Cell
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury,
death and/or property damage.
Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection of
leaks to check all connections.

SEQUENCE OF OPERATION

NOTE: Furnace control must be grounded for proper operation
or control will lock out. Control is grounded through
green/yellow wire routed to gas valve and gas valve mounting
bracket screw.
Follow the sequence of operation through the different modes.
Read and follow the wiring diagram very carefully.
The blower door must be installed for power to be conducted
through the blower door interlock switch ILK to the furnace
control CPU, transformer TRAN, inducer motor IDM, blower
motor BLWM, hot- -surface igniter HSI, and gas valve GV.
Sequence of Operation - - Heating
1. Call for Heat
A call for heat is intiated when a connection is observed
between thermostat terminals "R" & "W".
a. Pressure Sensor Verification:The control operates the
inducer in a manner to verify the pressure sensor null
value and span operation are within specification. If the
system is operating correctly, this test takes only a few
seconds. If the system is not functioning properly, the
control times out after a maximum 90 seconds and
displays the proper fault code.
b. Pre-purge: The heating cycle begins with operation of
the inducer at "Pre-purge" setting for the 30 seconds.
c. Igniter Warm-Up: After the pre-purge timer expires,
the control will set the inducer to the "Ignitor Warm-Up"
setting and energize the igniter for the Igniter Warm-up
period of 17 seconds.
NOTE: Inducer motor shuts off during igniter warm up period
and then come back on for the ignition trial.
d. Trial for Ignition: Once the igniter warm-up period has
expired, the control sets the inducer to the "Trial for
Ignition" setting and stabilizes the inducer speed to meet
the target pressure. The gas valve is then energized
allowing the flow of gas to the burner. The gas valve
remains open for the Trial for Ignition interval.
e. Flame Sense: While the gas valve is open, the control
monitors the flame sense circuit to detect the presence of
flame. If flame is not established during the Trial for
Ignition period of 4 seconds, the control de-energizes the
gas valve and operates the inducer for the Inter-purge
period.
f. Flame Stabilization: Once flame is established, the
control will set the inducer to the "Flame Stabilization"
setting and maintain the inducer operation at this setting
for the duration of the Flame Stabilization timing of 10
seconds.
g. Blower On-Delay: Once a successful ignition occurs,
A190291
the control will wait for the Heat Blower On-Delay of 25
seconds (time begins when the gas valve is energized) and
then energize the blower heating speed.
h. Heating Cycle Run: After the Flame Stabilization
period is completed, the control will continue to maintain
the heating cycle with the inducer running at the "Run"
setting until one of the following occurs:
35
WARNING