Tempstar furnace error codes are diagnostic signals that help identify problems with heating systems. This guide explains common codes, their meanings, troubleshooting steps, reset methods, safety considerations, and when to contact a professional. The goal is to provide clear, actionable information so homeowners can interpret codes and take appropriate next steps.
| Code | Indication | Quick Action |
|---|---|---|
| LED Flash 1 | Normal Operation / No Fault | None |
| LED Flash 2 | Open High Limit Or Flame Rollout Switch | Check airflow, filters, vents |
| LED Flash 3 | Flame Failure Or Internal Lockout | Reset, check gas supply |
| LED Flash 4 | Pressure Switch Or Vent Blockage | Inspect venting, clear obstructions |
| LED Flash 5 | Induced Draft Motor Fault | Check motor, wiring, capacitor |
| LED Flash 6 | Ignition Control Or Flame Sensor Issue | Clean sensor, inspect ignitor |
How Tempstar Furnace Error Codes Work
Tempstar furnaces use a control board that monitors operational components and reports status via an LED or digital display. Error codes typically appear as a pattern of LED flashes or a two-digit code and identify issues like ignition failure, limit switch trips, pressure switch faults, or venting problems.
The control board follows a diagnostic sequence during startup. If a safety device or sensor signals an out-of-range condition, the board logs the fault and may lock out the furnace until manual reset or corrective action occurs.
Common Tempstar Furnace Error Codes And Meanings
1. Normal Operation (One Flash)
One LED flash usually indicates normal furnace operation and no active faults. Homeowners do not need to take action when seeing this pattern.
2. Open High Limit Or Flame Rollout Switch (Two Flashes)
Two flashes commonly mean the high limit or rollout switch is open. This indicates excessive heat in the heat exchanger or poor combustion airflow. Immediate actions include checking air filters, ensuring return vents are not blocked, and verifying proper blower operation.
3. Flame Failure Or Internal Lockout (Three Flashes)
Three flashes often indicate repeated ignition attempts failed or a flame was not detected. Possible causes include no gas supply, faulty gas valve, dirty flame sensor, or failed ignitor. Check the gas supply, inspect the ignitor visually for cracks, and gently clean the flame sensor with fine emery cloth or steel wool.
4. Pressure Switch Or Venting Problems (Four Flashes)
Four flashes point to a pressure switch problem or blocked vent system. This affects induced-draft furnaces where the pressure switch confirms proper draft. Inspect intake and exhaust vents for debris, bird nests, or snow. Measure vacuum tubing and check connections for kinks or disconnections.
5. Induced Draft Motor Fault (Five Flashes)
Five flashes suggest the induced draft motor failed to operate or did not reach expected speed. Causes include motor failure, bad capacitor, or electrical supply issue. Verify the motor receives voltage and listen for unusual noises. If the motor hums but doesn’t run, the capacitor or motor bearings may be failing.
6. Ignition Control Or Flame Sensor Issue (Six Flashes)
Six flashes typically indicate ignition sequence trouble tied to the hot surface ignitor, spark module, or flame sensor. Replace the ignitor if it’s visibly damaged or has excessive resistance. Clean or replace the flame sensor if it shows heavy oxidation or pitting.
Steps For Basic Troubleshooting
Follow a systematic approach when addressing Tempstar furnace error codes. This reduces risks and avoids unnecessary repairs.
- Turn Off Power And Gas — Always switch off electrical power and gas supply before opening the furnace for inspection.
- Check Airflow — Inspect and replace clogged filters. Ensure supply and return vents are open and unobstructed.
- Inspect Vents — Visually check exterior intake and exhaust for blockages, nesting, or ice.
- Reset The Furnace — Many temporary faults clear after a reset. Turn power off for 30 seconds and restore to allow the control board to reinitialize.
- Clean Flame Sensor — Remove and gently clean the flame sensor with fine abrasive, then reinstall securely.
- Check Ignitor And Wiring — Look for cracked or broken ignitors and loose connectors. Replace damaged parts according to specifications.
- Test Pressure Switch And Tubing — Ensure tubing is intact and pressure switch closes on induced draft operation.
How To Reset A Tempstar Furnace
Resetting can clear non-persistent faults but should be done cautiously. Repeated resets without resolving root causes can mask serious issues.
- Locate the furnace switch or circuit breaker and turn off power to the unit.
- Wait 30 seconds to 2 minutes to allow the control board to clear temporary codes.
- Restore power and observe the LED or display during the startup sequence.
- If the same code returns, note the code and proceed to diagnostic steps or call a licensed technician.
When To Call A Professional
Contact a qualified HVAC technician when the fault indicates safety-related components, repeated lockouts, or issues beyond basic homeowner maintenance.
- Persistent flame failure or repeated ignition lockouts after cleaning and resetting.
- Open high limit or constant rollout switch trips suggesting heat exchanger or venting problems.
- Pressure switch and induced draft motor failures that require diagnostic tools and replacement parts.
- Any suspected gas leak, unusual odor, soot, rust, or visible cracks in the heat exchanger.
Safety Note: Gas-related problems and cracked heat exchangers can cause carbon monoxide hazards and require immediate professional attention.
Safety Tips And Carbon Monoxide Awareness
Furnaces burning natural gas or propane can produce carbon monoxide if combustion is incomplete or the heat exchanger is compromised. Install carbon monoxide detectors near sleeping areas and on each level of the home.
Regular inspection and maintenance reduce carbon monoxide risk. If CO alarm sounds or the furnace produces a strong gas odor, evacuate the home and call the gas company or emergency services immediately.
Routine Maintenance To Prevent Error Codes
Proactive maintenance reduces the chance of encountering furnace error codes and extends equipment life.
- Replace air filters every 1–3 months depending on usage and filter MERV rating.
- Schedule annual professional tune-ups before heating season to inspect burners, flame sensor, heat exchanger, and controls.
- Keep intake and exhaust vents clear of plants, debris, and snow.
- Ensure proper clearance around the furnace for adequate airflow and service access.
Parts And Tools Homeowners May Use Safely
Some minor tasks are suitable for homeowners with basic skills. Use proper safety precautions and consult the furnace manual for part specifications.
- Replacement filters sized for the specific furnace model.
- Fine emery cloth or Scotch-Brite pad for cleaning flame sensors.
- Multimeter to check voltage and continuity for simple electrical checks.
- Nut drivers and screwdrivers for access panels and sensor removal.
Avoid attempting gas valve, burner adjustments, or heat exchanger repairs, which require a licensed professional.
Interpreting Manufacturer-Specific Codes And Manuals
Tempstar furnaces may vary by model year and control board. Always consult the model-specific owner’s manual or service manual for exact LED flash patterns and detailed diagnostics.
When contacting support or a technician, provide the furnace model number, serial number, and the exact error code or LED flash pattern. This information speeds diagnosis and ensures correct replacement parts.
How Error Codes Relate To Warranty And Service
Many Tempstar units include warranties covering certain parts or labor for specific durations. Some warranties require proof of annual professional maintenance.
Document any professional service calls and keep receipts. If a control board or component fails within warranty, the manufacturer or authorized dealer can advise on coverage and claim procedures.
Resources And Next Steps For Homeowners
Use these resources when additional information or professional help is needed.
- Tempstar Owner’s Manual — model-specific error codes and wiring diagrams.
- Local licensed HVAC contractors — for advanced diagnostics and repairs.
- Certified carbon monoxide detector installers and electricians — for safety device support.
For recurring errors or any safety concern, prioritize contacting a licensed technician rather than continuing trial-and-error resets.
Quick Reference Cheat Sheet
| Symptom | Likely Cause | Homeowner Action |
|---|---|---|
| No Heat, LED 3 Flashes | Ignition/Flame Failure | Check gas supply, clean flame sensor, reset |
| Furnace Shuts Off, LED 2 Flashes | Limit/Rollout Switch Open | Check airflow, filters, verify blower operation |
| Furnace Won’t Start, LED 4 Flashes | Pressure Switch/Vent Block | Inspect vents, tubing, clear obstructions |
| Loud Draft Motor Noise, LED 5 Flashes | Induced Draft Motor Fault | Listen for bearing noise, check capacitor, call tech |
This guide aims to help homeowners understand and respond to Tempstar furnace error codes safely and effectively. For any doubt about a diagnosis or if the problem involves gas, heat exchanger integrity, or persistent lockouts, contact a licensed HVAC professional immediately.