American Standard HVAC ALLEGIANCE 2A7A5 Manual

The American Standard ALLEGIANCE 2A7A5 is a high-efficiency residential gas furnace designed for reliable heating performance. It features a durable heat exchanger, multi-speed blower motor, electronic ignition, integrated control board with diagnostic LED, and compatibility with various thermostat systems. Below are key sections covering safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Startup 4. Technical Specifications 5. Controls and Settings 6. Connecting Thermostat 7. Operating Instructions 8. Maintenance Procedures 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Durable aluminized steel heat exchanger, multi-speed direct-drive blower motor, hot surface ignitor, integrated control board, pressure switch, flame sensor, and vent connector.

Feature	Description
Heat Exchanger	Aluminized steel construction for durability and efficiency
Blower Motor	Multi-speed direct-drive for adjustable airflow
Ignition System	Hot surface ignitor for reliable lighting
Control Board	Integrated with diagnostic LED for error codes
Gas Valve	Regulates gas flow to burner assembly
Pressure Switch	Ensures proper venting before ignition
Flame Sensor	Detects burner flame for safety shutdown
Vent Connector	For exhaust vent connection
Filter Rack	Standard 1-inch filter slot
Electrical Connection	120V AC, 60Hz power input

Installation Requirements

Unpack and inspect unit for damage. Ensure proper location with adequate clearance.

Location: Install in level, dry area with minimum clearances as per manual.
Venting: Connect vent pipe per local codes; ensure proper slope and termination.
Gas connection: Use approved pipe; pressure test for leaks.
Electrical: Connect 120V power; ensure proper grounding.
Ductwork: Connect supply and return ducts securely.

WARNING! Installation must comply with all local codes. Gas connections must be leak-tested. Only qualified personnel should install.

First-Time Startup

After installation, perform initial startup sequence.

Verify all connections: Gas, electrical, venting, and ductwork.
Install air filter: Insert clean 1-inch filter into filter rack.
Power on: Turn on electrical power to furnace.
Set thermostat: Set to HEAT mode and temperature above room temp.
Observe operation: Listen for ignition sequence; check for proper flame.
Check airflow: Ensure adequate airflow from supply registers.

CAUTION! If gas odor is detected, shut off gas immediately and ventilate area. Do not attempt to restart.

Technical Specifications

Model: ALLEGIANCE 2A7A5
Type: Upflow Gas Furnace
Input BTU/h: 60,000 to 120,000 (varies by model)
AFUE: Up to 80%
Gas Type: Natural Gas (convertible to LP with kit)
Electrical: 120V AC, 60Hz, 5-10 Amps
Blower Speeds: Multi-speed for heating and continuous fan
Filter Size: Standard 1-inch (16x25x1 typical)
Vent Size: 3-inch or 4-inch PVC/ABS (category IV)
Dimensions: Varies by capacity; check unit label

Controls and Settings

Access control board inside furnace panel. Thermostat controls operation modes.

Control Board: Integrated with diagnostic LED (flashes error codes). DIP switches for blower speed adjustments.

Thermostat Settings: HEAT, COOL, OFF, FAN (Auto/On). Blower Speeds: Adjust via DIP switches on control board (refer to wiring diagram). Gas Valve: Adjust pressure per rating plate (qualified technician only). Limit Switches: Auto-reset high temperature protection.

Connecting Thermostat

Compatible with most 24V thermostats. Standard connections: R, W, G, Y, C.

Turn off power to furnace at disconnect or breaker.
Remove furnace access panel to expose control board.
Connect thermostat wires to corresponding terminals (R, W, G, etc.).
Secure connections and replace access panel.
Restore power and test thermostat operation.

Tip: Use 18-gauge thermostat wire. Ensure C (common) wire is connected for proper operation of digital thermostats.

Operating Instructions

Normal heating cycle operation.

Set thermostat to HEAT mode and desired temperature.
Furnace will initiate call for heat: blower pre-purge, ignitor heats, gas valve opens.
Flame sensor confirms ignition; burner operates.
Blower activates after heat exchanger warm-up delay.
When thermostat satisfied, gas valve closes, blower continues for post-purge.
Continuous fan mode available via thermostat FAN setting.

WARNING! Do not block supply or return registers. Ensure filter is clean for proper airflow.

Maintenance Procedures

Regular maintenance ensures efficiency and longevity.

Monthly: Check/replace air filter if dirty.
Annual: Professional inspection recommended.
Visual inspection: Check vent pipe for obstructions.
Blower cleaning: Vacuum blower compartment annually.
Burner inspection: Qualified technician should inspect burners and heat exchanger.

CAUTION! Turn off power and gas before any maintenance. Only qualified personnel should service gas and electrical components.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for safety standards. UL listed. FCC Part 15: Class B digital device. This product complies with U.S. federal efficiency standards. Copyright © American Standard Heating & Air Conditioning. For support, visit www.americanstandard.com or contact 1-800-428-4323.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, switch	Check breaker, thermostat settings, door switch.
No heat	Gas, ignition, filter	Verify gas supply; check for error codes; replace dirty filter.
Blower runs continuously	Thermostat fan setting	Set thermostat FAN to AUTO instead of ON.
Furnace cycles on/off frequently	Filter, airflow, limit switch	Replace filter; check for blocked vents; may be high limit tripping.
Error code flashing	Control board diagnostic	Count LED flashes; refer to error code chart in manual.

Reset: Power cycle furnace by turning off power for 30 seconds.

Service: 1-800-428-4323; www.americanstandard.com