American Standard Freedom 90 Furnace Installation Manual

The American Standard Freedom 90 is a high-efficiency gas furnace with AFUE ratings up to 96.7%, featuring a durable aluminized steel heat exchanger, variable-speed blower motor, electronic ignition system, and compatibility with air conditioning systems. Available in single-stage and two-stage models with heating capacities from 40,000 to 120,000 BTU/h. Below are key sections for safety, installation procedures, electrical connections, startup, and maintenance.

1. Safety Precautions 2. Pre-Installation Requirements 3. Unit Specifications 4. Installation Location 5. Venting System 6. Gas Supply Connection 7. Electrical Wiring 8. Ductwork Connection 9. Startup and Commissioning 10. Maintenance Procedures 11. Troubleshooting Guide

Safety Precautions

Critical safety information for installers and homeowners.

Hazard	Precaution
Gas Leaks	Check all connections with leak detection solution; never use open flame
Carbon Monoxide	Ensure proper venting; install CO detectors in living areas
Electrical Shock	Disconnect power before servicing; follow local electrical codes
Fire Hazard	Maintain proper clearances from combustible materials
Burn Risk	Allow unit to cool before handling internal components

Pre-Installation Requirements

Preparation steps before beginning installation.

Verify local codes and obtain necessary permits
Check furnace model number matches job requirements
Inspect unit for shipping damage
Ensure adequate clearance for service access
Confirm proper gas supply and electrical service available

WARNING! Installation must comply with all national and local codes. Professional installation recommended.

Unit Specifications

Models: AUX*036, AUX*060, AUX*080, AUX*100, AUX*120
Heating Capacity: 36,000 to 120,000 BTU/h
AFUE: Up to 96.7%
Gas Type: Natural Gas (convertible to LP)
Electrical: 115V, 60Hz, 1.2-5.5 Amps
Blower Motor: Variable-speed ECM
Heat Exchanger: Aluminized steel primary, stainless steel secondary
Venting: PVC pipe (2" or 3")
Dimensions: Varies by model (approx. 21"W x 21"D x 40"H)

Installation Location

Proper placement requirements for safe and efficient operation.

Indoor locations only - never install outdoors
Minimum clearances: 0" sides, 1" front, 0" rear, 1" top
Level, solid foundation required
Protect from water and excessive moisture
Ensure adequate combustion air supply

CAUTION! Do not install in areas where flammable liquids or vapors are present.

Venting System

PVC vent pipe installation for high-efficiency operation.

Use only PVC, CPVC, or ABS pipe approved for furnace venting
Maintain minimum slope of 1/4" per foot toward furnace
Maximum vent length: 100 feet equivalent (consult tables)
Install condensate drain trap per instructions
Terminate vents according to local codes (typically 12" above grade)

Tip: Seal all joints with PVC cement; support pipes every 4 feet.

Gas Supply Connection

Proper gas line installation and leak testing.

Install sediment trap upstream of gas valve
Use pipe joint compound rated for natural/LP gas
Install manual shutoff valve within 6 feet of unit
Pressure test at 14" W.C. for 10 minutes (no drop)
Check manifold pressure: 3.5" W.C. natural gas, 10" W.C. LP

WARNING! Never use matches or open flame to check for gas leaks.

Electrical Wiring

Electrical connections for power and thermostat.

Connection	Specification
Line Voltage	115V, 60Hz, dedicated 15A circuit
Low Voltage	24V thermostat connections (R, W, G, Y, C)
Grounding	Proper equipment grounding required
Blower Speeds	Multi-tap for cooling/heating speed selection
Safety Switches	Door interlock, rollout switches, pressure switches

Ductwork Connection

Proper duct system installation for optimal airflow.

Size return air duct to match furnace capacity
Install filter rack with minimum MERV 8 filter
Seal all duct connections with mastic or UL-181 tape
Ensure adequate return air from conditioned space
Balance system for proper airflow to all registers

CAUTION! Never operate furnace without filter installed.

Startup and Commissioning

Final checks and initial operation procedures.

Verify all connections secure and proper clearances
Set thermostat to lowest setting
Turn on gas supply and check for leaks
Apply power and set thermostat to call for heat
Check ignition sequence and flame appearance
Measure temperature rise (35-65°F range)
Verify proper vent operation and condensate drainage
Complete installation checklist and leave with homeowner

WARNING! Never bypass safety controls during startup.

Maintenance Procedures

Routine maintenance for optimal performance and longevity.

Monthly: Check filter, replace when dirty
Annual: Professional inspection and cleaning
Seasonal: Check vent termination, drain lines
As Needed: Clean flame sensor, check burners

Tip: Keep area around furnace clean and unobstructed.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No heat	Thermostat, power, gas supply	Check thermostat setting, circuit breaker, gas valve
Furnace short cycles	Dirty filter, restricted airflow	Replace filter, check for blocked vents/registers
Blower runs continuously	Thermostat fan setting	Set thermostat fan to AUTO mode
Error codes displayed	Various system faults	Refer to diagnostic chart in service manual
Unusual noises	Loose components, airflow issues	Check for loose panels, inspect blower wheel

Service: Contact qualified HVAC technician for complex issues.

Support: American Standard Customer Service 1-800-4-AMSTANDARD