Carrier Furnace Trouble Codes Manual

The Carrier Furnace Trouble Codes Manual provides comprehensive guidance for diagnosing and resolving common furnace issues through error code interpretation. This manual covers various Carrier furnace models with LED flash codes, diagnostic procedures, reset instructions, and maintenance tips to ensure optimal heating performance and system reliability.

Understanding Error Codes

Carrier furnaces use LED flash patterns to indicate specific system issues. The number and pattern of flashes correspond to different diagnostic codes that help identify the source of furnace problems.

Common Trouble Codes

Most frequent error codes encountered in Carrier furnace systems and their typical causes.

1. Code 13: Limit circuit lockout - Check airflow restrictions, dirty filter
2. Code 21: Gas valve circuit error - Verify gas supply and valve operation
3. Code 31: Pressure switch error - Inspect venting and switch operation
4. Code 33: Limit circuit fault - Check for blocked vents or registers
5. Code 41: Blower motor fault - Verify motor operation and capacitor
6. Code 42: Reversed polarity - Check electrical connections

WARNING! Always turn off power to furnace before performing any diagnostics.

Diagnostic Procedures

Step-by-step troubleshooting for common furnace issues.

1. Check thermostat settings and batteries
2. Verify power supply to furnace
3. Inspect air filter and replace if dirty
4. Check gas supply and valve operation
5. Examine venting system for obstructions
6. Test pressure switches and safety controls
7. Monitor LED flash patterns for error codes

CAUTION! Gas appliances can be dangerous; if unsure, contact professional technician.

Reset Instructions

• Power Cycle Reset: Turn off power at furnace switch or breaker for 30 seconds, then restore power
• Manual Reset: Press and hold reset button on control board for 3-5 seconds
• Thermostat Reset: Lower thermostat below room temperature, wait 5 minutes, then raise setting
• Lockout Reset: Turn power off for 1 minute, then restore to clear lockout condition

Maintenance Guidelines

Regular maintenance procedures to prevent furnace issues.

Safety Precautions

Critical safety information for furnace operation and troubleshooting.

1. Always turn off electrical power before servicing
2. Never bypass safety switches or controls
3. Ensure proper ventilation for combustion air
4. Install carbon monoxide detectors near sleeping areas
5. Keep flammable materials away from furnace
6. Verify gas connections are leak-free

DANGER! Carbon monoxide poisoning risk - ensure proper venting and annual inspections.

Professional Service

When to contact a qualified HVAC technician.

• Gas smell detected
• Carbon monoxide alarm activation
• Persistent error codes after reset
• Unusual noises or vibrations
• Inadequate heating performance
• Annual professional maintenance required

Warranty Information

Carrier furnace warranty coverage details.

• Heat Exchanger: 20-year limited warranty
• Parts: 10-year limited warranty
• Labor: 1-year limited warranty
• Registration: Complete product registration within 90 days of installation
• Transferable: Limited warranty transfer to subsequent homeowners

Technical Specifications

General specifications for Carrier furnace models.

• Input BTU: 40,000 - 120,000 BTU/hr
• Efficiency: 80% - 98% AFUE
• Voltage: 120V AC, 60Hz
• Gas Type: Natural Gas or LP
• Control Voltage: 24V AC
• Operating Temp: -30°F to 120°F ambient

Contact Information

Carrier customer support and service resources.

Emergency: For gas leaks or carbon monoxide detection, evacuate and call 911 immediately.