Tempstar Furnace Error Codes: Troubleshooting Guide and Solutions

The following guide explains Tempstar furnace error codes, what they mean, and practical steps for troubleshooting and resolving common issues safely. Homeowners can use this resource to identify fault codes, perform basic diagnostics, and know when to call a professional HVAC technician.

Code	Display/LED Pattern	Likely Cause	Suggested Action
Lockout	Continuous Red Or Specific Code	Repeated Failed Ignition Or Safety Lockout	Reset Power, Check Gas Supply, Call Technician
AF	Alternating Flash	Airflow Or Pressure Switch Problem	Check Filter, Vents, Pressure Switch Hose
PF	Pressure Switch Fault	Blocked Venting Or Broken Switch	Inspect Venting, Replace Switch If Needed
Ignition Fail	Flashing LED During Ignition	Ignitor Or Gas Valve Issue	Test Ignitor, Verify Gas Valve Operation
Flame Loss	Flame Sensor Error	Dirty Flame Sensor Or Weak Flame	Clean Sensor, Inspect Burner Flame

How Tempstar Furnaces Display Error Codes

Tempstar furnaces typically indicate problems through an LED on the control board, an alphanumeric code on a user interface, or both. Understanding the display method is the first step: locate the control panel access door, find the LED or control board label, and note the pattern—flashes, steady lights, or specific letters.

Common Tempstar Error Codes And Meanings

This section lists commonly encountered codes and concise explanations. Code presentation varies by model; always consult the furnace’s data plate or manual for model-specific definitions.

Lockout / Ignition Failure

Symptoms: Furnace tries to light multiple times then stops; continuous red LED or “lockout” message. Cause: Repeated ignition attempts failed due to faulty ignitor, gas supply, or control board. Action: Turn off power for 30 seconds to reset, check gas valve is on, inspect ignitor for cracks, and call a licensed technician if the fault persists.

AF / Airflow Fault

Symptoms: Furnace cycles off or displays an AF code; reduced heating. Cause: Dirty air filter, blocked return/supply vents, or blower motor issues. Action: Replace or clean the air filter, check vents and registers, verify blower operation; clean blower assembly if accessible and safe.

PF / Pressure Switch Fault

Symptoms: Code PF or clicking without successful ignition. Cause: Obstructed venting, clogged condensate drain, damaged pressure switch, or broken inducer motor. Action: Inspect vent termination for obstructions, clear condensate, check flexible tubing for kinks, and test the pressure switch continuity with a multimeter; replace if defective.

Flame Sensor Error (Loss Of Flame)

Symptoms: Furnace ignites but then shuts off; flame detected intermittently. Cause: Dirty flame sensor, weak flame from burners, or wiring issue. Action: Clean the flame sensor with fine emery cloth, ensure burners are clean and properly lit, and verify wiring connections.

Inducer Or Blower Motor Fault

Symptoms: Loud noises, failure to start, error indicating motor fault. Cause: Failed bearings, motor capacitor failure, electrical issues, or obstruction. Action: Inspect for debris, test motor capacitor and continuity, and replace motor or capacitor as required by a technician.

Step-By-Step Troubleshooting Checklist

1. Confirm Power And Thermostat Settings: Verify circuit breaker is on, switches are set correctly, and thermostat calls for heat.
2. Reset The Furnace Safely: Turn off power at the breaker for 30–60 seconds, then restore power to clear transient lockouts.
3. Inspect Air Filter And Vents: Replace dirty filters and ensure vents/registers are open and unobstructed.
4. Check Gas Supply: Confirm gas shutoff valve is open and other gas appliances operate normally; if not, call the gas utility.
5. Examine Vents And Flue: Look for nests, debris, or snow blocking intake/exhaust terminations.
6. Clean Flame Sensor And Burners: Remove and clean the flame sensor, and vacuum burner area if soot or dust is present.
7. Listen For Unusual Noises: Squeals, rattles, or thumps point to blower or inducer issues requiring professional service.

How To Safely Reset A Tempstar Furnace

Many temporary faults clear after a reset, but frequent resets hide underlying problems. To reset: turn off thermostat call for heat, switch off power at the furnace switch or breaker, wait 30–60 seconds, then restore power and call for heat. If the furnace locks out again immediately, do not attempt repeated resets; contact an HVAC technician.

When To Contact An HVAC Professional

Some issues require licensed technicians: suspected gas leaks, persistent ignition failures, control board faults, blocked vents requiring access to roof terminations, or any situation involving disassembly, gas valve testing, or replacement of sealed components. Call a professional if the error code recurs after basic troubleshooting, or if the homeowner detects a gas smell.

Safety Precautions And Gas Leak Response

Safety is paramount. If a homeowner smells gas—rotten egg odor—immediately leave the house, avoid using phones or electrical switches indoors, and call the gas company or 911 from a safe location. Do not attempt DIY fixes for suspected gas leaks or valve repairs.

Maintenance Tips To Prevent Error Codes

• Replace Or Clean Air Filters Every 1–3 Months Depending On Usage.
• Schedule Annual Professional Tune-Ups Before Heating Season.
• Keep Vent Terminations Clear Of Snow, Ice, Leaves, And Debris.
• Clean Flame Sensor And Burner Assembly During Annual Service.
• Maintain Adequate Clearance Around The Furnace For Ventilation And Access.

Interpreting Less Common Alphanumeric Codes

Some Tempstar units present alphanumeric codes (for example, “E5”, “E7”, or model-specific codes). Always cross-reference the furnace’s model number and manual because identical codes can have different meanings across model lines. If the manual is unavailable, the manufacturer’s website and authorized dealer resources often publish error code charts.

Resources And Documentation

For accurate, model-specific information, consult the furnace’s user manual or the Tempstar official website. Manufacturer documentation provides exact code definitions, wiring diagrams, and safety warnings. Local licensed HVAC contractors can access manufacturer technical bulletins for complex or recurring faults.

Quick Reference Table: Common Codes And Immediate Actions

Code	Immediate Homeowner Action
Lockout / Ignition Fail	Reset power once, check gas supply, call technician if it returns.
AF / Airflow	Replace filter, clear vents, check blower operation.
PF / Pressure Switch	Inspect venting, clear condensate, check tubing for leaks.
Flame Loss	Clean flame sensor, inspect burners, call for service if unresolved.
Inducer Motor Fault	Check vent blockage; if noisy or nonfunctional, call technician.

Tips For Working With An HVAC Technician

When calling a professional, provide the furnace model and serial number, the exact error code or LED pattern, recent events (power outages, storms), and steps already taken. This information helps the technician diagnose more efficiently and may reduce diagnostic fees.

Warranty, Parts, And Replacement Considerations

Check the furnace warranty before paying for repairs; some components may be covered. For older units with recurring error codes and high repair costs, consider replacement. Modern high-efficiency furnaces offer improved diagnostics, energy savings, and reliability.

Summary And Next Steps

Tempstar furnace error codes serve as diagnostic signals that guide safe troubleshooting and repairs. Homeowners should perform basic checks—filters, vents, power, and a reset—then contact qualified HVAC service for ignition, gas, or control board issues. Proper maintenance and timely professional service minimize disruptions and extend equipment life.