Carrier Gas Furnace Model 58STA090 Manual

The Carrier 58STA090 is a high-efficiency gas furnace with 90% AFUE rating, featuring two-stage heating operation, variable-speed blower motor, durable heat exchanger construction, electronic ignition system, and comprehensive safety controls. Designed for residential heating applications with input capacity of 90,000 BTU/hr. Below are key sections for 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. Wiring and Connections 7. Operating Instructions 8. Maintenance Procedures 9. Safety Features 10. Regulatory Information 11. Troubleshooting

Features at a Glance

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

Feature	Description
AFUE Rating	90% Annual Fuel Utilization Efficiency
Heating Stages	Two-stage operation for enhanced comfort
Blower Motor	Variable-speed ECM for quiet operation
Heat Exchanger	Aluminized steel construction
Ignition System	Hot surface electronic ignition
Gas Valve	Two-stage modulating gas valve
Control Board	Integrated furnace control
Pressure Switches	Draft and vent safety monitoring
Flame Sensor	Flame rectification safety
Filter System	Standard 1-inch filter slot

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

Location: Install in dry, clean area with adequate combustion air and service clearance.
Venting: Use approved PVC vent pipe for Category IV venting system.
Gas Supply: Connect to proper gas line with sediment trap; pressure test required.
Electrical: 120V AC power supply with proper grounding.
Ductwork: Ensure proper sizing and sealing of supply/return ducts.

WARNING! Gas furnaces produce carbon monoxide; proper venting is critical. Installation must comply with all local codes.

First-Time Startup

Qualified technician must perform initial startup and commissioning.

Verify installation: Check all connections, venting, and gas line integrity.
Electrical power: Turn on furnace disconnect and thermostat.
Gas supply: Open main gas valve and appliance shutoff valve.
System check: Control board will perform self-test and ignition sequence.
Adjustments: Set temperature rise, gas pressure, and blower speeds per specifications.

CAUTION! Never attempt to adjust gas pressure without proper training and equipment.

Technical Specifications

Model: 58STA090
Input Capacity: 90,000 BTU/hr
Output Capacity: 81,000 BTU/hr
AFUE: 90%
Gas Type: Natural Gas
Stages: Two-stage heating
Blower Type: Variable-speed ECM
Electrical: 115V/60Hz/1Ph
Max External Static Pressure: 0.80 in. w.c.
Venting: Category IV (PVC)
Dimensions: Refer to installation manual

Controls and Settings

Integrated furnace control board with status LED for diagnostics. Thermostat connections for conventional or advanced control systems.

Control Board: LED status light, dip switch settings for blower speeds, furnace configuration options.

Thermostat Wiring: R (24V power), W/W1/W2 (heat stages), G (fan), C (common), Y/Y1/Y2 (cooling stages if applicable).

DIP Switch Settings: Adjust blower speeds for heating and cooling modes, configure staging delays, set temperature rise parameters.

Wiring and Connections

Follow wiring diagram provided with unit. All electrical work must comply with NEC and local codes.

Disconnect power before servicing any electrical components.
Verify proper voltage at furnace (115-120V AC).
Connect thermostat wires to control board terminals.
Ensure proper grounding of all electrical components.
Check high-voltage and low-voltage wiring for secure connections.

Tip: Use wire nuts and electrical tape for all splices; keep wiring neat and organized.

Operating Instructions

Normal operation controlled by thermostat. Two-stage operation provides enhanced comfort.

Set thermostat to desired temperature and HEAT mode.
Furnace will initiate ignition sequence when heat is demanded.
First stage operates for moderate heating needs.
Second stage engages for greater heating demand or extreme cold.
Variable-speed blower adjusts airflow for optimal efficiency.
System cycles off when thermostat setpoint is reached.

WARNING! Never operate furnace with access panels removed or safety devices bypassed.

Maintenance Procedures

Regular maintenance ensures optimal performance and safety.

Monthly: Check and replace air filter as needed.
Annual: Professional inspection and cleaning recommended.
Visual inspection: Check vent system, burners, and heat exchanger.
Cleaning: Vacuum burners, blower compartment, and flame sensor.
Testing: Verify safety controls and gas pressure settings.

CAUTION! Turn off gas and electrical power before performing any maintenance.

Safety Features

Multiple safety systems protect against hazardous conditions: Flame rollout switches, high-limit switches, pressure switches, flame sensor, and ignition control safety timing.

Regulatory Information

UL listed and ANSI certified. Complies with U.S. Department of Energy efficiency standards. Manufactured to meet or exceed industry safety standards. For technical support, contact Carrier at 1-800-CARRIER or visit www.carrier.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, safety lockout	Check disconnect switch, thermostat settings, reset if locked out.
No heat	Gas supply, ignition failure	Verify gas valve open, check for ignition attempts, inspect flame sensor.
Short cycling	Dirty filter, high limit	Replace air filter, check for restricted airflow, verify proper venting.
Blower not running	Motor, capacitor, control board	Check blower motor operation, test capacitor, verify control signals.
Lockout condition	Safety device tripped	Reset power, check error codes, identify tripped safety switch.

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

Service: 1-800-CARRIER; www.carrier.com