Arcoaire furnaces use two ignition approaches, and the pilot light is a common maintenance point for older models. This guide explains how to identify whether an Arcoaire furnace has a standing pilot, steps to light it safely, common problems, maintenance practices, and when to call a professional. The information aims to help homeowners understand what to check and how to approach typical issues without compromising safety.

Understanding An Arcoaire Furnace Pilot Light

Older Arcoaire furnaces often rely on a standing pilot light connected to a thermocouple. When lit, the pilot ignites the main burner through the gas valve. Some Arcoaire models use electronic ignition, which does not have a continuously burning pilot. Identifying the ignition type is essential before attempting any service. Signs of a standing pilot include a small flame near the burner and a visible thermocouple near the pilot assembly. Modern units typically feature a gas valve with a Pilot, Off, and On setting paired with an electronic ignition system.

Knowing the ignition type helps prevent unnecessary steps. If a model uses electronic ignition, lighting the furnace is done by the automatic ignition sequence held by the control board or igniter rather than a manual pilot flame. For those unsure about their model, consult the furnace’s data plate, user manual, or the installer’s notes. Incorrect procedures can lead to gas leaks or equipment damage, so accuracy in model identification is critical.

Safety Essentials For Pilot Light Work

Working with gas involves inherent risks, including fire hazards and the potential for carbon monoxide exposure. A safe approach hinges on preparation, correct identification of the ignition type, and adherence to manufacturer guidelines. If a strong gas odor is detected, evacuate the area immediately and contact emergency services. Never attempt to bypass safety devices or force a flame if the gas control seems compromised. All work should begin with power shutoff to the furnace to prevent accidental activation during maintenance.

Turn off the thermostat and switch off the furnace at the power switch before opening any panels.
Shut off the gas supply at the main valve if accessible and confirms there is no gas odor before proceeding.
Keep combustibles away from the furnace and ensure adequate ventilation in the area.
If there is any doubt about gas lines, ventilation, or flame combustion, contact a licensed technician promptly.
Never attempt to light a pilot if signs of damage, corrosion, or a cracked heat exchanger are present.

Step-By-Step Lighting Process For Arcoaire Furnaces

This lighting procedure applies to models with a standing pilot light. If the furnace uses electronic ignition, these steps do not apply and ignition is controlled by the ECM or control module. In all cases, follow the manufacturer’s manual for model-specific instructions. For safety, perform all actions only when comfortable and prepared to stop if anything seems unsafe.

Locate the gas shutoff valve and ensure the knob is in the Off position before beginning. If the valve is not accessible, skip to the safety reminder that says to call a professional.
Turn off the thermostat and switch off power to the furnace. Wait 5–10 minutes to allow residual gas to clear the area.
Remove the furnace access panel to expose the burner and pilot assembly, taking care not to touch hot surfaces.
Identify the gas control knob, which typically has Off, Pilot, and On positions. Turn the knob to Off, then wait a few minutes to ensure the line depressurizes.
Turn the knob to Pilot and depress or hold the knob to engage the pilot valve. If there is a separate ignite button, use it as instructed by the manual while keeping the knob pressed.
Light the pilot with a long-reach lighter or striker from a safe distance. Keep the flame steady on the pilot flame for the required duration, usually about 60 seconds, as specified by the manual.
Continue to hold the knob in the Pilot position after lighting, then slowly release it. If the pilot remains lit, turn the knob to On to allow the main burner to operate when the thermostat calls for heat.
Replace the access panel and restore power. Turn the thermostat to heat and observe the flame. If the flame does not light or goes out, discontinue and proceed to troubleshooting or call a professional.

Note: If the model uses electronic ignition, skip lighting steps and consult the manual for troubleshooting ignition faults or contact a licensed technician. Do not attempt to force ignition on models without a standing pilot.

Troubleshooting Common Pilot Light Problems

Pilot light issues can stem from gas supply problems, sensor misalignment, or ignition system faults. The following outlines common symptoms, likely causes, and practical steps. Each section emphasizes safety and when to seek professional help.

Pilot Won’t Light or Stay Lit: A misaligned or dirty thermocouple can prevent the valve from staying open. Check that the thermocouple is correctly positioned in the flame and not bent away from it. A dirty pilot orifice or clogged burner can also block ignition. If misalignment or dirt is suspected, cleaning or replacement is advised by a technician. Insufficient gas pressure due to an issue with the gas valve or regulator can also prevent ignition and may require service.
Pilot Flame Is Weak or Flickering: A weak flame often indicates clogged orifice, insufficient gas supply, or drafts near the vent. Inspect for obstructions in the burner area, confirm the gas line pressure, and ensure there are no strong air currents around the furnace. A fluctuating flame can also signal a failing thermocouple or ignition assembly needing replacement.
Flame Lights But Goes Out When Thermostat Calls Heat: This can indicate a failing thermocouple, an improperly seated pilot assembly, or a gas valve that is not holding open when the burner starts. Realigning the pilot tip, cleaning the pilot assembly, or replacing the thermocouple can resolve the issue. If the problem persists, professional service is recommended to check the gas valve and electrical connections.
Gas Odor or Leaks Detected: A noticeable gas smell requires immediate action. Do not light or operate electrical devices; evacuate the area and call the gas utility or emergency services. Do not attempt to repair gas lines yourself.
Intermittent Ignition on Electronic Systems: For models with electronic ignition, intermittent ignition faults can occur due to dirty igniters, cracked electrodes, or a failing control board. Cleaning with manufacturer-approved solutions or replacing faulty igniters or ignition modules is typically performed by a technician.

Maintenance And Replacement Parts For Arcoaire Furnaces

Regular maintenance helps extend the life of an Arcoaire furnace and reduces the likelihood of pilot-related failures. The following table highlights key components associated with pilot operation, their roles, and typical replacement considerations.

Part	Role	Replacement Guidance
Thermocouple	Generates a small electrical signal to keep the gas valve open when the pilot is lit.	Replace if bent, damaged, or unresponsive; typical life is 3–5 years depending on use and environment.
Pilot Assembly / Orifice	Supports flame stability and proper ignition	Clean regularly; replace if clogged or damaged; professional service is recommended for removal and cleaning.
Gas Control Valve	Regulates gas flow to pilot and main burner	Replace if it fails to hold open or consistently shuts off; usually handled by licensed technicians.
Igniter (Electronic Ignition Models)	Initiates the flame sequence	Replace if cracked, dirty, or fail to spark; requires precise alignment.
Flame Sensor	Detects flame presence and ensures safe operation	Clean to restore proper signaling; replace if unresponsive.

The table focuses on core components tied to pilot operation. Regular professional inspections can identify wear or misalignment before failures occur. Homeowners should never attempt to disassemble gas components beyond basic cleaning; gas work requires proper training and local code compliance.

When To Call A Pro

Certain situations demand professional service rather than home repair. If there is a persistent gas odor, a pilot flame that won’t light after repeated attempts, a flame that goes out after ignition, or frequent thermocouple or valve failures, a licensed HVAC technician should evaluate the system. Additionally, any signs of gas leaks, cracked heat exchangers, or irregular burner flames warrant immediate professional assessment. For models under warranty, authorized service can protect coverage and ensure code-compliant repairs.

Frequently Asked Questions

Do all Arcoaire furnaces use a standing pilot? No. Many newer Arcoaire models use electronic ignition and do not have a standing pilot. The presence of a visible pilot and thermocouple typically indicates an older, standing-pilot configuration.
How can a homeowner tell if the furnace has a standing pilot? Look for a small flame near the burner area and a thermocouple positioned in the pilot flame. The gas control knob may show Pilot, Off, and On positions, which is characteristic of standing-pilot systems.
What should be done if a pilot light keeps going out? Check for thermocouple alignment, flame quality, and any drafts near the vent. If these checks fail, or if the flame repeatedly goes out, consult a professional to inspect the gas valve and ignition components.
Is it safe to relight a pilot light after a gas odor suspected situation? If there is a gas odor, do not attempt to light the pilot. Leave the area immediately and contact the gas utility or emergency services.
How often should an Arcoaire furnace be serviced? Annual professional maintenance is recommended to keep ignition systems, burners, and safety devices functioning correctly and to verify gas pressure and venting integrity.