Lennox Furnace Reset Button: How to Locate, Use, and Troubleshoot

Lennox Furnace Reset Button information covers identification, correct reset procedures, safety considerations, common causes for trips, and professional service guidance. This article explains where the reset button is typically located, step-by-step reset instructions, diagnostic checks after a reset, and maintenance tips to reduce future resets. The guidance is intended for general U.S. homeowners and property managers seeking reliable, safe furnace operation and aligns with Lennox system designs and common HVAC industry practices.

Item	Quick Summary
Typical Location	On the furnace control panel, near blower motor or transformer, or behind access panel
Primary Use	Restart motor or control after overload or lockout; not a long-term fix
Reset Steps	Turn off power → wait 1–5 minutes → press reset once → restore power → observe
When Not To Reset	Smell of gas, visible damage, repeated trips, water leaks, or electrical arcing

What The Lennox Furnace Reset Button Is And Why It Exists

The Lennox furnace reset button is a manual safety or overload reset incorporated into certain furnace components such as the blower motor, draft inducer motor, or integral control module. Its purpose is to permit a safe restart after the protective device trips due to overheating, motor stall, or detected fault conditions. The reset restores normal operation only after the underlying cause cools or is corrected.

Common Locations For The Reset Button On Lennox Furnaces

Location varies by model. Common places include the blower compartment near the motor, the control board area behind the main access panel, the furnace exterior near the service valve or junction box, or on attached components like the condensate pump or high-limit assembly.

Models With Access-Panel Buttons: Many mid- to high-efficiency Lennox models place service buttons behind the front panel; accessing them requires removing the door and sometimes disconnecting power first.

Blower Motor Or Limit Switch Reset: Some resets are recessed red or black push buttons on the blower housing or high-limit switch assembly, designed to be pressed with a non-conductive tool.

How To Identify If A Reset Button Is Present

Check the furnace user manual or the model-specific wiring diagram sticker inside the access panel for labeled terminals or reset functions. If printed materials are unavailable, photograph the control board and blower area and consult Lennox online resources or a qualified technician. Appliance stores and OEM parts diagrams are also useful for identification.

Step-By-Step Safe Reset Procedure

Before any interaction, confirm the furnace is not under warranty terms that require technician intervention for resets. Safety remains paramount; if gas odor, smoke, or visible damage exists, do not attempt a reset.

1. Turn Off Power: Switch off the furnace at the thermostat and the dedicated breaker or service switch. This prevents electrical shock and allows components to cool.

2. Wait For Cooling: Allow 1–5 minutes for motors or limit switches to cool. Some components require longer; if the motor is hot to the touch, wait additional time before proceeding.

3. Locate The Reset Button: Remove the access panel if necessary. Identify the reset by color (often red or black) and labeling. Use a flashlight to confirm markings.

4. Depress The Reset Once: Press firmly but not excessively. Hold for 1–2 seconds, then release. Multiple pushes can damage the mechanism or mask persistent faults.

5. Restore Power And Observe: Turn the breaker or service switch back on and set the thermostat to call for heat. Observe the furnace through a full cycle, noting ignition sequence, blower startup, and unusual noises or odors.

Diagnosing After A Reset: What To Watch For

After a reset, key diagnostic checks include verifying that the burner lights and remains stable, the blower motor runs smoothly, no error codes are displayed on the control board, and there is no recurrent tripping within a short time. If the reset button trips again quickly, the problem is not resolved and further investigation is needed.

Common Observations And Their Meanings: Repeated trips indicate an ongoing overload, airflow restriction, failed motor bearings, or electrical fault. A single trip followed by normal operation may reflect transient overload or temporary blockage.

Common Causes For A Reset Trip On Lennox Furnaces

Several frequent causes prompt the reset button to trip: restricted airflow due to dirty filters or closed vents, failed blower motor or capacitor, obstructed return ducts, clogged condensate drains in high-efficiency models, faulty limit switches, or electrical supply issues such as short circuits or voltage irregularities.

Airflow Restrictions: Dirty filters, blocked returns, or a frozen coil can cause overheating and force the high-limit switch to trip, requiring reset.

Motor Failures: Worn bearings or failing capacitors cause motors to overheat under load and trigger the motor overload reset.

Condensate And Drain Problems: In high-efficiency Lennox furnaces, a blocked condensate drain or pump failure can cause water safety switches to trip and require manual or automated reset after clearing.

When Not To Press The Reset Button

Reset should not be used as a workaround for persistent or hazardous faults. Avoid resetting when there is a strong odor of gas, visible signs of electrical burning, leaking fuel lines, frequent resets, or when the furnace exhibits unsafe behavior such as backdrafting or flames outside the combustion chamber. In these cases, power should remain off and a licensed HVAC technician or gas utility should be contacted.

Tools And Safety Precautions

Tools are minimal: a non-conductive flashlight, insulated screwdriver to remove panels (where needed), and protective gloves. Strongly recommend shutting off electrical power before panel removal. Avoid metallic tools near live wiring. If working near gas components, ensure the gas supply remains off until inspection is complete.

Control Board Codes And Diagnostics

Many Lennox furnaces include control boards that display LED flash codes useful for troubleshooting. After a reset, note any blinking patterns and cross-reference with the model-specific code chart to determine ignition failures, limit trips, or motor faults. Recording codes before and after reset can speed repair diagnostics.

Maintenance To Reduce Future Resets

Routine maintenance reduces reset events. Replace air filters regularly, ideally every 1–3 months, depending on occupancy and indoor air quality. Schedule annual preventive maintenance with an HVAC technician for inspection of motors, bearings, belts, gas valves, burners, and control settings.

Seasonal Checklist: Clean burners and flame sensors, check condensate lines on high-efficiency units, lubricate motors if applicable, verify gas pressure and venting, and inspect electrical connections for corrosion or looseness.

When To Call A Professional HVAC Technician

Contact a licensed technician when reset trips recur, if control board codes indicate component failure, if gas odors or corrosion are present, or if diagnostics point to electrical or combustion issues. Professionals can safely test motors, capacitors, flame sensors, pressure switches, limit switches, and gas-system integrity.

Emergency Signs Requiring Immediate Service: Persistent burning smell, visible flames, smoke, or repeated ignition lockouts should prompt immediate shutdown and professional response.

Replacement Parts And OEM Guidance

If the reset button or associated component is defective, OEM replacement parts from Lennox or authorized distributors are recommended. After replacement, the system should be tested through multiple heat cycles to ensure the root cause is corrected and proper operation is restored.

Using third-party or generic parts for critical safety functions can void warranties and may not meet required safety standards; documentation and part numbers on the control board or blower housing assist in ordering correct replacements.

Common Myths And Misconceptions

One myth is that the reset button is a general “fix-all” for furnace problems. In reality, it is a protective device that masks symptoms until the underlying issue is resolved. Another misconception is that frequent resets are harmless; repeated manual resets can stress electrical components and conceal hazardous conditions.

Cost Considerations And Typical Repairs

Simple fixes such as replacing a filter or clearing a condensate line are low-cost preventive measures. Motor or control board repairs can range from moderate to significant depending on parts and labor. Technicians will provide cost estimates after diagnostics; persistent or complex electrical and combustion issues typically incur higher repairs.

Resources And Where To Find Model-Specific Information

Model-specific manuals, wiring diagrams, and LED code charts are available on Lennox’s official website and in product literature. Authorized Lennox dealers provide technical support and service records. Homeowner forums and reputable HVAC publications offer practical tips but should not replace professional diagnostics for safety-critical issues.

Key Takeaways And Best Practices

• Reset Button Function: A safety feature for overload and fault recovery, not a permanent fix.
• Locate And Operate Safely: Shut power off, wait for cooling, press reset once, restore power, and observe operation.
• Investigate Causes: Repeated trips indicate airflow, motor, electrical, or condensate problems requiring repair.
• Maintenance Matters: Regular filter changes and annual professional service minimize trips and extend equipment life.
• Call A Pro For Unsafe Conditions: Gas smells, visible damage, smoke, or persistent lockouts require immediate professional attention.

Further Reading And Helpful Links

For detailed model information, consult Lennox product manuals and official support pages. Manufacturer documentation provides wiring diagrams, LED code explanations, and authentic part numbers which are crucial for safe repairs and accurate troubleshooting.

Note: This article provides general guidance and is not a substitute for professional HVAC service. Always prioritize safety and compliance with local codes and manufacturer recommendations.