SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service maintenance, or use can cause explosion, fire, electrical shock, or other conditions which may cause death, personal injury, or property damage. Consult a qualified installer, service agency, or your distributor or branch for information or assistance. The qualified installer or agency must use factory-authorized kits or accessories when modifying this product. Refer to the individual instructions packaged with the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective clothing, and work gloves. Have a fire extinguisher available. Read these instructions thoroughly and follow all warnings or cautions included in literature and attached to the unit. consult local building codes, the current editions of the National Fuel Gas Code (NFGC) NFPA 54/ANSI Z223.1, and the National Electrical Code (NEC) NFPA 70.
In Canada refer to the current editions of the National Standards of Canada CAN/CSA-B149.1 and .2 Natural Gas and Propane Installation codes, and Canadian Electrical Code CSA C22.1
Recognize safety information. This is the safety-alert symbol 
. When you see this symbol on the unit and in instructions or manu- als, be alert to the potential for personal injury. Understand these signal words: DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in per- sonal injury or death. CAUTION is used to identify unsafe practic- es which may result in minor personal injury or product and prop- erty damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.
!WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Before installing or servicing system, always turn off main power to system and install lockout tag. There may be more than one disconnect switch. Turn off accessory heater power switch if applicable.
!WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could result in personal injury or equipment damage.
Puron (R-410A) systems operate at higher pressures than standard R-22 systems. DO NOT use R-22 service equipment or components on Puron (R-410A) equipment. Ensure service equipment is rated for Puron (R-410A).
!CAUTION
CUT HAZARD
Failure to follow this caution may result in personal injury.
When removing access panels or performing maintenance functions inside your unit, be aware of sharp sheet metal parts and screws. Although special care is taken to reduce sharp edges to a minimum, be extremely careful when handling parts or reaching into the unit.
INTRODUCTION
The 577D--A packaged unit is a fully self-contained combination Category I gas heating/electric air conditioner designed for outdoor installation (See Fig. 1). Standard units are shipped in a horizontal-discharge configuration for installation on a rooftop, or on cement slab (See Fig. 4 for roof curb dimensions). Standard
units can be converted to downflow (vertical) discharge configurations for rooftop applications.
Models with an N in the thirteenth position of the model number are dedicated Low NOx units designed for California installations. These models meet the California maximum oxides of nitrogen (NOx) emissions requirements of 40 nanograms/joule or less as shipped from the factory and must be installed in California Air Quality Management Districts or any other regions in North America where a Low NOx rule exists.
In gas heating mode, this unit is designed for a minimum continuous return-air temperature of 55_F (13_C) db and a maximum continuous return-air temperature of 80_F (27_C) db. Failure to follow these return-air temperature limits may affect reliability of heat exchangers, motors, and other components.
NOTE: Low NOx requirements apply only to natural gas installations.
RECEIVING AND INSTALLATION
Check Equipment
IDENTIFY UNIT
The unit model number and serial number are printed on the unit informative plate. Check this information against shipping papers.
INSPECT SHIPMENT
Inspect for shipping damage before removing packaging material. If unit appears to be damaged or is torn loose from its anchorage, have it examined by transportation inspectors before removal. Forward claim papers directly to transportation company. Manufacturer is not responsible for any damage incurred in transit. Check all items against shipping list. Immediately notify the nearest distributor office if any item is missing. To prevent loss or damage, leave all parts in original packages until installation.
If the unit is to be mounted on a curb in a downflow application, review “Configuring Units for Downflow Discharge” to determine which method is to be used to remove the downflow panels before rigging and lifting into place. The panel removal process may require the unit to be on the ground.
Provide Unit Support
IMPORTANT: The unit must be secured to the curb by installing screws through the bottom of the curb flange and into the unit base rails. When installing large base units onto the common curb, the screws must be installed before allowing the full weight of the unit to rest on the curb. A minimum of six screws are required for large base units. Failure to secure unit properly could result in an unstable unit. See Warning near Rigging/Lifting information and accessory curb instructions for more details.
For hurricane tie downs, contact distributor for details and PE (Professional Engineering) Certificate, if required.
ROOF CURB
Install accessory roof curb in accordance with instructions shipped with curb (See Fig. 4). Install insulation, cant strips, roofing, and flashing. Ductwork must be attached to curb.
IMPORTANT: The gasketing of the unit to the roof curb is critical for a water tight seal. Install gasketing material supplied with the roof curb. Improperly applied gasketing also can result in air leaks and poor unit performance.
Curb should be level to within 1/4 in. (6.35 m) (See Fig. 2). This is necessary for unit drain to function properly. Refer to accessory roof curb installation instructions for additional information as required.
