The Day And Night furnace pilot light is a small but critical component that ignites the main burner on older gas furnaces. This article explains how pilot lights work, common problems, safe relighting procedures, maintenance tips, and when to contact a licensed HVAC technician. Readers will learn practical troubleshooting steps and safety best practices to keep the furnace operating reliably.
| Issue | Likely Cause | Quick Fix |
|---|---|---|
| Pilot Won’t Stay Lit | Faulty thermocouple or draft | Replace thermocouple; seal drafts |
| No Pilot Flame | Gas supply or clogged orifice | Check gas valve; clean orifice |
| Weak Yellow Flame | Dirty pilot or low gas pressure | Clean pilot; inspect gas pressure |
| Smells Of Gas | Gas leak | Shut off gas; ventilate; call gas company |
How A Day And Night Furnace Pilot Light Works
A pilot light is a continuously burning flame that ignites the furnace’s main burners when the thermostat calls for heat. The Day And Night brand often uses a standing pilot with a thermocouple or thermopile sensor to detect flame presence and allow the gas valve to remain open.
The thermocouple generates a small electrical voltage when heated by the pilot flame; if the thermocouple fails, the gas valve closes as a safety measure. Understanding this simple interaction explains why pilot problems are common and why safety mechanisms prevent gas flow when the flame is absent.
Common Pilot Light Problems And Diagnoses
Pilot Light Won’t Stay Lit
This symptom usually indicates a failing thermocouple, improper pilot flame alignment, or drafts blowing the flame away. The thermocouple may become coated with soot or degrade over time and lose its voltage-generating ability.
Pilot Light Is Yellow Or Weak
A healthy pilot flame is typically blue with a steady inner cone. A yellow, flickering, or weak flame can indicate a dirty pilot orifice, low gas pressure, or combustion air problems. Yellow flames can produce soot and carbon monoxide and should be addressed promptly.
Pilot Light Will Not Ignite
When the pilot won’t light, common causes include a closed gas valve, a clogged pilot orifice, an empty gas supply from the utility, or an ignition knob not turned to the correct position. Mechanical issues with the valve or the gas regulator can also prevent ignition.
Gas Smell Around Furnace
If there is a clear smell of gas, the pilot light problem may be related to a leak. This is a serious safety issue that requires immediate action: shut off the gas at the meter or appliance valve, ventilate the area, and call the gas company or a licensed professional.
Step-By-Step Pilot Light Relighting Procedure
Relighting a Day And Night furnace pilot light can be performed safely by following manufacturer instructions and local codes. If the furnace manual is available, always follow those steps first. The following procedure is a general guide.
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Turn Off The Furnace: Set the thermostat to OFF and turn off the gas control valve by rotating the knob to the OFF position, then wait at least 5 minutes for any accumulated gas to dissipate.
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Locate The Pilot Assembly: Access the burner compartment and find the pilot light assembly, pilot tube, and gas control knob labeled PILOT, ON, and OFF.
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Turn The Gas Control To PILOT: Rotate the knob to PILOT and depress if required while lighting.
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Light The Pilot: Use a long-stem piezo igniter or match to light the pilot while holding the knob depressed for 20–30 seconds to allow the thermocouple to heat up and generate voltage.
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Release The Knob And Confirm: Slowly release the knob; the pilot should remain lit. Turn the control to ON and set the thermostat back to heat to verify burner ignition.
If the pilot will not stay lit after several attempts, shut off the gas and contact a professional.
Thermocouple And Thermopile: Roles And Replacement
The thermocouple is a sensor that detects the pilot flame and signals the gas valve to stay open. Thermopiles are similar but yield higher voltage for systems with electronic gas valves or millivolt thermostats.
Symptoms of a failing thermocouple include a pilot that lights but won’t remain on. Replacement is a common DIY repair for competent homeowners, but the job requires shutting off gas, removing the old sensor, and installing a correctly sized replacement. Improper installation can create safety hazards, so consider a licensed HVAC technician if unsure.
Cleaning And Maintenance Of Pilot Orifice And Burner
Regular maintenance reduces pilot light issues. The pilot orifice can become clogged by dirt, spider webs, or soot, reducing flame strength. Cleaning improves combustion and reliability.
Basic maintenance steps include turning off gas and power, using compressed air or a fine wire to clear the orifice gently, and wiping the pilot and surrounding area with a dry cloth. For the main burner assembly, cleaning should be performed annually by a qualified technician.
Drafts, Ventilation, And Combustion Air Concerns
Pilot lights are sensitive to air movement. Strong drafts from open windows, attic access, or improperly installed seals can extinguish the pilot. Ensure tight access panels and adequate combustion air for the furnace room.
Modern homes are more airtight, which can reduce available combustion air and affect older furnaces. If the furnace is in a confined space, evaluate whether additional vents or makeup air are needed to maintain safe operation.
When To Replace A Standing Pilot With Electronic Ignition
Replacing a standing pilot system with an electronic ignition or hot-surface ignition can improve efficiency and safety by eliminating continuous pilot gas use. Electronic ignition systems only use gas when the furnace is firing, reducing gas consumption.
Consider replacement if the furnace is older, pilot-related repairs are frequent, or energy savings are a priority. A licensed HVAC contractor can evaluate compatibility, estimate cost, and perform conversion while ensuring code compliance.
Safety Precautions And Gas Leak Response
Safety is paramount when dealing with gas appliances. If a gas odor is detected, avoid using electrical switches, phones inside the building, or anything that could create a spark. Evacuate, ventilate, and call the gas company from a safe location.
Never attempt to repair gas valves, regulators, or gas piping unless qualified. Improper work can lead to leaks, fire, or carbon monoxide hazards. Annual inspections by a licensed technician reduce risk and help spot early signs of failure.
Troubleshooting Checklist For Day And Night Furnace Pilot Light
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Confirm Gas Supply: Verify other gas appliances are working and the service is active.
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Check Pilot Flame Characteristics: A healthy flame is blue with a steady cone.
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Inspect Thermocouple Connections: Ensure tight, clean connections at the gas valve.
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Clean Pilot Orifice: Remove debris and ensure unobstructed gas flow.
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Look For Drafts: Seal gaps and check access panels to reduce airflow across the pilot.
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Test Gas Valve Operation: If the valve does not respond, call a technician.
Costs And When To Call A Professional
Common pilot-related repairs like thermocouple replacement are usually low to moderate in cost, often between $100 and $300 depending on parts and labor. Cleaning orifice and basic service may be less expensive if included in annual maintenance.
Call a licensed HVAC professional when the pilot will not stay lit after troubleshooting, when gas smells are present, when gas valve replacement is suspected, or when conversion to electronic ignition is desired. Certified technicians ensure safe repairs and code compliance.
Parts And Tools Commonly Needed
Common parts and tools for pilot light maintenance include replacement thermocouples or thermopiles, screwdriver set, adjustable wrench, long-reach lighter or piezo igniter, compressed air, and replacement pilot orifices if required.
Always use OEM or approved replacement parts for Day And Night furnaces to maintain proper operation and safety certification.
Documentation, Codes, And Manufacturer Guidance
Consult the Day And Night furnace manual for model-specific instructions and specifications. Local building codes and utility company requirements can govern gas appliance work and conversion to electronic ignition.
Keeping service records, serial numbers, and receipts helps when scheduling professional maintenance and when verifying warranty coverage.
Frequently Asked Questions About Day And Night Furnace Pilot Light
How Often Should The Pilot Be Inspected?
Annual inspection during routine furnace service is recommended. The pilot orifice and thermocouple benefit from periodic checks to ensure reliability and safety.
Is It Safe To Leave A Pilot On Continuously?
Older furnaces with standing pilots are designed to keep the pilot lit continuously, but this consumes a small amount of gas. Electronic ignition systems eliminate standby gas use and are often recommended for energy savings.
Can A Homeowner Replace A Thermocouple?
An experienced homeowner can replace a thermocouple following correct safety steps, but if there is any uncertainty, a licensed HVAC technician should perform the work to ensure safe installation and testing.
Key Takeaways For Reliable Pilot Light Performance
Regular maintenance, prompt attention to yellow or weak flames, and immediate action on gas odors are essential to keep a Day And Night furnace pilot light operating safely. Replacing aging standing pilot systems with electronic ignition can improve efficiency and reduce service needs. When in doubt, consult a licensed professional for repairs or conversions.