GC9C96 Service Manual
SYSTEM OPERATION
16
To change the main blower speed in COOLING mode, follow
the following steps:
1. Press the left or right switch until LED displays “AC1
“(for single stage COOLING) or “AC2 “(for two-stage
COOLING). Press the center switch and LED will display
the selected speed number as Fxx (xx: Blower speed
number from 1 to 9).
2. The control will rotate available speed number every time
left/right switches are pressed. All 9 speeds are available
for both Single and Two Stage cooling.
3. When the center switch is pressed, the current displayed
speed will be selected, and control will apply the newly
selected speed in next cooling call.
THERMOSTATCALL AVAILABLESPEEDS
Y/Y1
F01
F02
F03
F04(DEFAULT)
F05
F06
F07
F08
F09
THERMOSTATCALL AVAILABLESPEEDS
Y2
F01
F02
F03
F04
F05(DEFAULT)
F06
F07
F08
F09
Duct systems and register sizes must be properly designed
for the C.F.M. and external static pressure rating of the
furnace. Ductwork should be designed in accordance with
the recommended methods of “Air Conditioning Contractors
of America” manual D.
A duct system should be installed in accordance with
Standards of the National Board of Fire Underwriters for
the Installation of Air Conditioning, Warm Air Heating and
Ventilating Systems, Pamphlets No. 90A and 90B.
A return air lter is not supplied with the furnace. The installer
must supply a means of ltering all of the return air. Filter(s)
shall comply with UL900 or CAN/ULC-S111 Standards. If
the furnace is installed without lters, and is not covered by
the warranty.
Upow furnaces with air delivery of less than 1800 CFM:
Use one side return or one bottom return ductwork connection.
Upow furnaces with air delivery of 1800 CFM or higher:
Use two side returns or one side return and one bottom return
connection.
Guide dimples locate the side and bottom return cutout
locations. Use a straight edge to scribe lines connecting the
dimples. Cut out the opening on these lines. An undersized
opening will cause reduced airflow. For bottom return
connection, remove the bottom of the cabinet before setting
the furnace on the raised platform or return air duct.
A closed return duct system must be used, with the return
duct connected to the furnace. NOTE: Ductwork must never
be attached to the back of the furnace. Supply and return
connections to the furnace may be made with exible joints
to reduce noise transmission, if desired. If a central return is
used, a connecting duct must be installed between the unit
and the utility room wall so the blower will not interfere with
combustion air or draft. The room, closet, or alcove must not
be used as a return air chamber.
When the furnace is used in connection with a cooling unit,
the furnace should be installed in parallel with or on the
upstream side of the cooling unit to avoid condensation in
the heating element. With a parallel ow arrangement, the
dampers or other means used to control the ow of air must
be adequate to prevent chilled air from entering the furnace
and, if manually operated, must be equipped with means to
prevent operation of either unit unless the damper is in the
full heat or cool position.
When the furnace is heating, the temperature of the return
air entering the furnace must be between and .
Depending on the installation and/or customer preference,
diering lter arrangements can be applied. Filters can be
installed in the central return register and a side panel external
lter rack kit (upow lter kit # EFR02 As an alternative
a media air lter or electronic air cleaner can be used as
the requested lter. Refer to the following minimum lter
requirement charts for determination of the minimum lter
area to ensure proper unit performance. The following gures
show possible lter locations.