American Standard HVAC Allegiance 18 Manual

The American Standard Allegiance 18 is a high-efficiency residential air conditioning system featuring 18 SEER rating, durable construction, quiet operation, and compatibility with various American Standard furnaces and air handlers. This manual covers safety guidelines, installation procedures, operation instructions, maintenance requirements, and troubleshooting tips for proper system performance and longevity.

Features at a Glance

Key components: Outdoor condenser unit, indoor coil, refrigerant lines, thermostat, and electrical connections.

Installation Requirements

Professional installation recommended. Unpack and inspect all components before installation.

1. Select location: Outdoor unit on level pad with proper clearance (minimum 24 inches all sides).
2. Install indoor coil: Match to compatible furnace or air handler.
3. Connect refrigerant lines: Braze connections following proper procedures.
4. Electrical connections: Connect to dedicated 230V circuit with proper disconnect.
5. Connect thermostat: Use appropriate wiring for system control.
6. Vacuum and charge: Evacuate system to 500 microns before charging with R-410A.

WARNING! Installation must be performed by qualified HVAC technician. Improper installation can cause injury or system damage.

First-Time Startup

After installation, follow proper startup procedure.

1. Verify all connections: Check electrical, refrigerant, and drain lines.
2. Set thermostat: Configure for cooling mode with desired temperature.
3. Power sequence: Turn on indoor unit first, then outdoor unit.
4. Check operation: Verify proper airflow, temperature drop, and system pressures.
5. Test safety controls: Ensure high-pressure switch, low-pressure switch, and other safeties function properly.

CAUTION! Do not operate system without proper refrigerant charge. Monitor pressures during initial operation.

Technical Specifications

• Model Series: Allegiance 18 (4A7A8)
• Cooling Capacity: 1.5 to 5 tons (18,000 to 60,000 BTU/h)
• SEER Rating: Up to 18 SEER
• Refrigerant: R-410A
• Electrical: 230V, 60Hz, 1-phase
• Operating Range: 55°F to 115°F outdoor temperature
• Sound Rating: As low as 72 dB(A)
• Maximum Working Pressure: 600 psi high side, 200 psi low side
• Line Set Size: 3/8" liquid, 3/4" or 7/8" suction (varies by tonnage)
• Warranty: 10-year compressor, 5-year parts

System Controls

Primary control through thermostat. System includes built-in protection controls.

Thermostat Settings: COOL, OFF, FAN (AUTO/ON), temperature setpoint, system mode.

System Controls: High-pressure switch, low-pressure switch, compressor overload protection, fan delay, freeze protection.

LED Indicators: Outdoor unit includes diagnostic LEDs for troubleshooting (green = normal, amber = warning, red = fault).

Service Ports: Standard 1/4" SAE ports for pressure gauges on both high and low sides.

Connecting Components

Proper connection between indoor and outdoor units is critical.

1. Turn off power at disconnect and indoor unit before making connections.
2. Refrigerant lines: Use clean, dehydrated copper tubing with proper insulation.
3. Electrical: Follow wiring diagram for low-voltage (thermostat) and line-voltage connections.
4. Drain line: Connect condensate drain to proper drainage system with trap.
5. Communication: Some models include communicating capability for advanced diagnostics.

Tip: Always use nitrogen purge when brazing to prevent oxidation inside tubing.

Operating Modes

System operates in cooling mode only (heat provided by separate furnace or heat pump).

1. Cooling mode: Compressor and outdoor fan operate with indoor blower.
2. Fan only: Indoor blower circulates air without cooling.
3. Auto mode: System cycles based on thermostat settings.
4. Dehumidification: Enhanced moisture removal during cooling operation.
5. Delay features: Compressor short-cycle protection (5-minute delay).

WARNING! Do not operate system in heating mode unless properly configured as heat pump. This is cooling-only equipment.

Maintenance Schedule

Regular maintenance ensures optimal performance and efficiency.

Care & Cleaning

Turn off power before any cleaning. Outdoor unit: Remove debris from coil fins. Indoor coil: Professional cleaning recommended.

CAUTION! Do not use pressure washer on outdoor coil. Use fin comb for straightening bent fins. Keep vegetation at least 24 inches from unit.

Regulatory Information

UL listed and meets ASHRAE standards. EPA regulations apply for refrigerant handling. California Proposition 65 warning: This product may contain chemicals known to cause cancer or reproductive harm. For technical support, contact American Standard at 1-800-628-8317 or visit www.americanstandardair.com.

Troubleshooting

Reset: Turn off power at disconnect for 5 minutes, then restore.

Service: 1-800-628-8317; www.americanstandardair.com