American Standard TUC120 Furnace Manual

The American Standard TUC120 is a high-efficiency gas furnace with variable-speed blower technology, offering up to 97% AFUE efficiency. This two-stage furnace features quiet operation, durable heat exchanger construction, 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 Setup 4. Technical Specifications 5. Controls and Operation 6. Thermostat Connection 7. Maintenance Procedures 8. Safety Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Two-stage gas valve, variable-speed ECM blower motor, aluminized steel heat exchanger, integrated control board, pressure switches, and flame sensor.

Feature	Description
Two-stage gas valve	Provides efficient heating at low and high stages
Variable-speed blower	ECM motor for quiet operation and energy efficiency
Heat exchanger	Durable aluminized steel construction
Control board	Integrated diagnostics and system monitoring
Pressure switches	Safety verification of proper venting
Flame sensor	Ensures proper ignition and flame detection
Gas connection	1/2" NPT gas inlet
Electrical connection	120V AC, 60Hz power supply
Vent connections	2" PVC for intake and exhaust
Filter access	Standard 1" or 4" media filter compatible

Installation Requirements

Unpack and inspect all components. Ensure proper clearances and venting.

Location: Install in dry, level area with adequate combustion air and service access.
Venting: Use 2" PVC pipe for intake and exhaust; maintain proper slope and termination clearances.
Gas connection: Use approved pipe compound; pressure test for leaks.
Electrical: Connect to 120V AC grounded outlet; follow local codes.
Ductwork: Ensure proper sizing and sealing for optimal airflow.

WARNING! Installation must be performed by qualified HVAC technician. Gas furnaces can produce carbon monoxide.

First-Time Setup

Power on furnace; follow startup sequence.

System check: Control board performs self-diagnostic test.
Thermostat setup: Connect compatible thermostat; set to heat mode.
Gas pressure adjustment: Verify and adjust manifold pressure per specifications.
Airflow verification: Check static pressure and adjust blower speed if needed.
Combustion analysis: Verify proper vent operation and combustion efficiency.

CAUTION! Never bypass safety controls. Ensure proper ventilation during operation.

Technical Specifications

Model: TUC120
AFUE Efficiency: Up to 97%
Heating Capacity: 40,000-120,000 BTU/h (multiple sizes)
Stages: Two-stage heating
Blower Type: Variable-speed ECM
Gas Type: Natural gas
Electrical: 120V AC, 60Hz
Vent Material: 2" PVC
Sound Level: Ultra-quiet operation
Warranty: Limited lifetime heat exchanger

Controls and Operation

Access control board via front panel. LED status lights indicate system operation and error codes.

Control Board: POWER switch, status LED, diagnostic codes, dip switch settings.

Operation: Two-stage heating provides efficient operation. First stage operates at 65% capacity for mild weather, second stage at 100% for extreme cold. Variable-speed blower adjusts airflow for optimal comfort and efficiency.

Thermostat Connection

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

Turn off power to furnace before connecting thermostat.
Match thermostat wires to control board terminals.
For two-stage operation: Connect W1 and W2 terminals.
Verify proper operation in both heating stages.

Tip: Use programmable thermostat for maximum energy savings.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning.
Seasonal: Verify proper vent operation and clearances.
Biannual: Inspect heat exchanger for cracks or damage.
As needed: Clean flame sensor and check gas pressure.

WARNING! Only qualified technicians should perform internal maintenance. Turn off gas and electrical power before servicing.

Safety Features

Multiple safety systems protect against hazardous conditions: High-limit switch, flame rollout switch, pressure switches, flame sensor, igniter safety lockout.

Care & Cleaning

Turn off power before cleaning. Keep area around furnace clear of combustible materials. Clean exterior with damp cloth only.

CAUTION! Never use water or cleaning solutions on electrical components. Keep combustion air intake clear of debris.

Regulatory Information

UL certified; meets ANSI Z21.47 standards. CSA certified for Canada. Complies with DOE energy efficiency standards. Copyright © American Standard; all rights reserved. For support, visit www.americanstandard.com or contact 1-800-572-2246.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power/thermostat	Check circuit breaker; verify thermostat settings and batteries.
No heat	Gas supply/ignition	Verify gas valve on; check for ignition attempts; inspect flame sensor.
Short cycling	Filter/airflow	Replace dirty filter; check for blocked vents or registers.
Blower not working	Motor/control	Check blower door switch; verify control board signals.
Error codes flashing	System fault	Refer to diagnostic chart in service manual; reset if applicable.

Reset: Turn power off for 30 seconds, then restore.

Service: 1-800-572-2246; www.americanstandard.com