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820SB/821SB: Installation, Start–Up, Operating and Service and Maintenance Instructions
e. Furnace should cycle off within 2 minutes. If gas does not shut
off within 2 minutes, determine reason draft safeguard switch did
not function properly and correct condition.
NOTE: Should switch remain open longer than 3 minutes, furnace
control board will lockout the furnace for 3 hours. To reset furnace
control board, turn thermostat below room temperature or from HEAT to
OFF and turn 115-V power OFF, then back ON.
f. Remove blockage from furnace vent elbow.
g. Switch will auto-reset when it cools.
h. Re-install vent connector.
3. Check Pressure Switch(es)
This control proves operation of the draft inducer blower.
a. Turn off 115-V power to furnace.
b. Disconnect inducer motor lead wires from wire harness.
c. Turn on 115-V power to furnace.
d. Set thermostat to "call for heat" and wait 1 minute. When
pressure switch is functioning properly, hot surface igniter
should NOT glow and control diagnostic light flashes a status
code (31.1). If hot surface igniter glows when inducer motor is
disconnected, shut down furnace immediately, determine reason
pressure switch did not function properly and correct condition.
e. Turn off 115-V power to furnace.
f. Reconnect inducer motor wires, replace outer door, and turn on
115-V power.
g. Blower will run for 90 seconds before beginning the call for heat
again.
h. Furnace should ignite normally.
Checklist
• Put away tools and instruments. Clean up debris.
• Check Input/Output gas pressure
• Check heat rise per application static pressure
• Cooling CFM per application static pressure
• Verify that blower-OFF delay time is selected as desired.
• Verify that blower and burner access doors are properly installed.
• Cycle test furnace with room thermostat.
• Check operation of accessories per manufacturer's instructions.
• Review User's Guide with owner.
• Attach literature packet to furnace.
SERVICE AND MAINTENANCE PROCEDURES
Untrained personnel can perform basic maintenance functions such as
cleaning and replacing air filters. All other operations must be performed
by trained service personnel. A qualified service person should inspect
the furnace once a year.
WARNING
!
FIRE, INJURY OR DEATH HAZARD
Failure to follow this warning could result in personal injury, death
and/or property damage.
The ability to properly perform maintenance on this equipment requires
certain knowledge, 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.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
!
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental pollution.
Remove and recycle all components or materials (i.e. oil, refrigerant,
control board, etc.) before unit final disposal.
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury or death,
or property damage.
Before installing, modifying, or servicing system, main electrical
disconnect switch must be in the OFF position and install a lockout tag.
There may be more than one disconnect switch. Lock out and tag
switch with a suitable warning label. Verify proper operation after
servicing.
!
ELECTRICAL OPERATION HAZARD
Failure to follow this caution may result in improper furnace operation
or failure of furnace.
Label all wires prior to disconnection when servicing controls. Wiring
errors can cause improper and dangerous operation.
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. Since this furnace can be installed
in any of the 4 positions (see
component location accordingly.
ELECTRICAL CONTROLS AND WIRING
The electrical ground and polarity for 115-V wiring must be properly
maintained. See
Fig. 24
for field wiring information and
furnace wiring information.
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
There may be more than one electrical supply to the furnace. Check
accessories and cooling unit for additional electrical supplies that must
be shut off during furnace servicing. Lock out and tag switch with a
suitable warning label.
NOTE: If the polarity is not correct, the STATUS LED on the control
will flash rapidly and status code (10.1) is displayed. This will prevent
the furnace from heating. The control system also requires an earth
ground for proper operation of the control and flame-sensing electrode.
The 24-V circuit contains an automotive-type, 3-amp. fuse located on
the control, see
Fig.
29. Any 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 3-amp. fuse. The control LED will
display status code (24.1) when fuse needs to be replaced.
Proper instrumentation is required to service electrical controls. The
control in this furnace is equipped with a status code LED
(Light-Emitting Diode) and Major/Minor 3 digit codes to aid in
installation, servicing, and troubleshooting. Status codes can be viewed
at the sight glass in blower access door. The furnace control LED is
36
CAUTION
WARNING
CAUTION
Fig.
3), you must revise your orientation to
WARNING
Fig. 47
for
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