Bryant 581A/B manual Application Data, Wiring of Outdoor-Air Thermostat, Condenser Coil Protection

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 036-240) 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 rooftop unit is equipped with an economizer, low ambient controls 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):

580F/581B036-091, 120, 121	115 F
580F/581B103, 150, 151	125 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.

W1
	FIELD-INSTALLED
	OUTDOOR-AIR THERMOSTAT
W2
	TO UNIT THERMOSTAT
a48-7481	CONNECTIONS

Wiring of Outdoor-Air Thermostat

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 eco- nomical option provides substantial corrosion protection 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.

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