Bryant 581C - Manual (Page 293)

293
APPLICATION DATA
1. CONDENSATE DRAIN PAN — A sloped condensate drain
pan is supplied on all units. The condensate pan must be
externally trapped. Condensate drains are located on both
the bottom and end of the unit.
2. DUCTWORK — All ductwork must be attached to flanges.
If no flanges are present, they must be field supplied.
Secure vertical discharge ductwork to roof curb. For hori-
zontal discharge applications, attach ductwork to flanges.
Field-supplied flanges can be attached to horizontal dis-
charge openings and all ductwork attached to flanges.
3. THERMOSTAT — Use of 2-stage cooling thermostat is rec-
ommended for all units equipped with economizer. A
2-stage cooling thermostat is required for size 090-300
units with integrated economizer.
4. HEATING-TO-COOLING CHANGEOVER — All units are
automatic changeover from heating to cooling when auto-
matic changeover thermostat and subbase are used.
5. AIRFLOW — Units are draw-thru on cooling and blow-thru
on heating.
6. MAXIMUM AIRFLOW — To minimize possibility of conden-
sate blow-off from evaporator, airflow through units should
not exceed 500 cfm/ton (sizes 024-240) and 11,250 cfm
(size 300).
7. MINIMUM AIRFLOW — Minimum airflow for cooling is
300 cfm/ton (sizes 036-240) and 280 cfm/ton (300 units).
Refer to Heating Capacities and Efficiencies table for mini-
mum heating airflow.
8. MINIMUM AMBIENT OPERATING TEMPERATURE —
Minimum ambient operating temperature for size 036-150
standard units is 25 F. With accessory Motormaster® I, II, or
IV units can operate at outdoor temperatures down to –20 F.
Unit sizes 155-300 are designed to operate at outdoor tem-
peratures down to 40 F. With accessory Motormaster I or
Motormaster V control, units can operate at outdoor tem-
peratures down to –20 F.
NOTE: Under most application circumstances, if the roof-
top unit is equipped with an economizer, low ambient con-
trols are not required. Unless the outdoor air is
unsatisfactory for free cooling due to high temperature,
excessive humidity, or poor air quality, outdoor air should
be used.
9. MAXIMUM OPERATING OUTDOOR-AIR TEMPERA-
TURE — Maximum outdoor operating temperature for
cooling is shown below (60 Hz):
581B,C024-150 125 F
580F036-151 115 F
579F/580F180-240 120 F
579F/580F300 125 F
581A036-155 125 F
581A180 120 F
581A210 125 F
581A240 125 F
581A300 125 F
10. HIGH ALTITUDES — These may require a change to the
gas orifice. Refer to Altitude Compensation tables.
11. MINIMUM HEATING ENTERING AIR TEMPERATURE —
The minimum temperature of air entering the dimpled heat
exchanger is 50 F continuous and 45 F intermittent for alu-
minum heat exchangers and 40 F continuous and 35 F
intermittent for stainless steel heat exchangers. To operate
at lower mixed-air temperatures, a field-supplied outdoor-
air thermostat must be used to initiate both stages of heat
when the temperature is below the minimum required tem-
perature to ensure full fire operation. Wire the outdoor-air
thermostat (part no. HH22AG106) in series with the second
stage gas valve as shown below. Set the outdoor-air
thermostat at 35 F for stainless steel heat exchangers or
45 F for aluminum heat exchangers. This temperature set-
ting will bring on the second stage of heat whenever the
ambient temperature is below the thermostat set point.
Indoor comfort may be compromised when heating is initi-
ated using low entering air temperatures with insufficient
heating temperature rise.
12. MOTOR DATA — Due to Bryant’s internal unit design
(draw-thru over the motor), air path, and specially designed
motors, the full horsepower (maximum continuous bhp)
listed in the Physical Data tables and the notes following
each Fan Performance table can be utilized with extreme
confidence.
Using Bryant motors to the values listed in the Physical
Data, Fan Performance, and Evaporator-Fan Motor Data
tables will not result in nuisance tripping or premature motor
failure. In addition, the unit warranty will not be affected.
13. THRU-THE-BOTTOM CONNECTIONS — The accessory
thru-the-bottom connections are needed to ensure proper
connections when routing wiring and piping through the
basepan and roof curb. This accessory is used for electric
and control power only or electric, control power, and gas
piping depending on which accessory is selected.
14. FIELD-SUPPLIED FAN DRIVES — If the factory drive sets
must be changed to obtain other wheel speeds, consult the
nearest Browning Manufacturing Co. sales office with the
required new wheel speed and the data from Physical Data
tables (center distances, motor and fan shaft diameters,
motor horsepower) for a modified drive set selection. For
minor speed changes, the fan sheave size should be
changed. (Do not reduce the size of the motor sheave; this
will result in reduced belt horse-power ratings and reduced
belt life.) All indoor fan pulleys are adjustable. See physical
data tables for rpm adjustment ranges.
15. CONDENSER COIL PROTECTION
a. PRE-COATED ALUMINUM FIN COILS have a durable
epoxy-phenolic coating applied to the fin prior to the fin
stamping process to provide protection in mildly corro-
sive coastal environments. Pre-coated coils have an
inert barrier between the aluminum fin and copper tube.
This barrier electrically disconnects the dissimilar metals
to minimize the potential for galvanic corrosion. This
economical option provides substantial corrosion protec-
tion beyond the standard uncoated coil construction.
b. COPPER-FIN COILS provide increased corrosion resis-
tance in moderate coastal environments where industrial
air pollution is not present. All copper coils eliminate bi-
metallic construction to eliminate the potential for gal-
vanic corrosion. Application in industrial environments is
not recommended due to potential attack from sulfur,
sulfur oxide, nitrogen oxides, carbon and several other
industrial airborne contaminants. In moderate seacoast
environments, copper-fin coils have extended life com-
pared to standard or pre-coated aluminum-fin coils.
W1
W2
FIELD-INSTALLED
OUTDOOR-AIR THERMOSTAT
TO UNIT THERMOSTAT
CONNECTIONS
Wiring of Outdoor-Air Thermostat
a48-7481