Pilot lights serve as an ignition source for gas furnaces and allow the furnace to create heat. However, pilot light can go out or won’t stay lit due to thermocouple issues, a dirty pilot orifice, or a faulty gas valve.
In this case, knowing how to relight pilot light on furnace can help you keep the pilot light stay lit and warm the house again. However, if this doesn’t work, you’ll need to troubleshoot and fix the underlying problem to keep the pilot light stay lit.
Table of Contents
How To Relight The Pilot Light On The Furnace?
You must keep the pilot light lit to ignite the main burners when the thermostat requires heat. If the pilot light goes out, you can try to relight it following these processes. However, if it doesn’t work, you’ll need to troubleshoot and fix the faulty part to keep the pilot light lit.
1. Turn Off The Furnace Power
Turn off the thermostat and electrical panel switch that controls the furnace. Doing so will prevent damaging your equipment and causing electrical shock.
2. Turn Off The Gas Supply
Turn off the valve on the gas line to stop the gas supply to the furnace. If you smell gas after turning off the valve, turn on the fan and open all windows and doors to remove gas from the home. Wait around 5 to 10 minutes to make sure all gases are dissipated. Otherwise, it can cause an explosion during the relighting pilot light.
3. Find Pilot Light
The pilot light is a small flame that is placed near the furnace’s bottom side.
4. Relight The Pilot Light
Turn the gas valve knob to the pilot position and hold it in the same position for a few seconds. Then light the pilot light by pressing the connected spark igniter until it makes a snap sound. Wait for around 30 seconds so the thermocouple can heat up. Then you can release the knob. You must keep the knob depressed during heating the thermocouple.
If the pilot light stays ignited after release, the thermocouple is functioning properly and the furnace will fire up after turning on. But if the pilot light goes out again, the thermocouple gets damaged and you have to replace it to relight the pilot light successfully.
5. Check Your Furnace
Finally, turn on your furnace. It should fire up immediately and start warming your home.
Is it Dangerous if The Pilot Light Goes Out On Your Furnace?
The pilot light is a part of the safety system on the furnace. However, the danger of the pilot light going out depends on whether your furnace has a safety pilot or not.
If your furnace has a safety pilot, the light that goes out won’t cause any damage to your system. The safety pilot will prevent gas from releasing when the pilot goes out to avoid causing any danger. On such devices, pilot lights work with flame detection sensors.
But if your device doesn’t have a safety pilot, gas leaking can cause fire, explosion, and breathing problems whenever the pilot light goes out. So flame sensors are required universally in every gas system to shut off the gas automatically when the pilot light goes out.
However, some modern furnace systems come with an electronic igniter instead of a pilot light that controls the circuit heating before releasing gas for combustion.
Why Does A Pilot Light Go Out On A Furnace?
Several factors can cause a pilot light to go out on a furnace. Here are some common reasons:
Thermocouple Issues
A thermocouple is a safety equipment that detects the pilot light’s heat. If the thermocouple gets damaged or misaligned, it won’t produce sufficient voltage to keep the gas valve open. So the pilot light can go out.
Dirty Pilot Orifice
The pilot orifice can collect dirt, dust, or debris over time and disturb the gas flow to the pilot light. Pilot tubes can also get blocked due to dirt and affect gas flow. Hence the pilot light can go out.
Faulty Gas Valve
If gas valve malfunctions, the pilot light won’t get consistent gas flow and can go out.
Ventilation Issues
Poor ventilation in the furnace area can also damage the pilot light. Blockage in the venting system can allow hot gases to escape safely.
Damaged Safety Switch
The faulty safety switch of furnace can shut off the gas supply and damage the pilot light. Even with the pilot light on, a damaged safety switch can also shut off the gas erroneously.
Gas Pressure Problems
If there is not enough gas pressure in the supply line, the furnace system may cause a weak pilot flame and damage the pilot light.
How To Fix The Pilot Light on Furnace That Won’t Stay Lit?
Pilot lights in gas furnaces produce heat in the home. An activated pilot light in the furnace indicates, there is no gas leaking in the system. So if pilot light doesn’t stay lit, you have to fix it immediately to ensure a consistent heat supply to the home. Follow this procedure to fix your pilot light that won’t stay lit:
Open The Gas Furnace
Turn off the pilot light on furnace and stop gas flowing to furnace using the shut-off valve. Wait around 30 minutes so the furnace becomes cool and you can open it safely. Then open the shield that covers the pilot light so you can inspect inside properly.
Check Thermocouple
A thermocouple in a gas furnace determines if the pilot light is on or off by sensing the heat the pilot light makes. But a thermocouple can get bent, misaligned, or stuck in place and turn off the pilot light even when it should be on. Hence pilot light can go off frequently.
If so, try to bend the cool thermocouple to line it up with the pilot tube and turn on the pilot light. If your thermocouple isn’t bent or misaligned, it may get dirty or clogged preventing the pilot light from staying on. If so, clean the thermocouple using fine-grain sandpaper.
Check Pilot Tube
Pilot tube also gets dirt, clogged, or blocked and causes the pilot light to go out. However, it’s a bit difficult to determine if the pilot tube gets dirty or clogged as it is placed inside the system. Use a needle to reach inside and scrub the pilot tube. This should clean the blockage of the pilot tube.
Check Gas Furnace
Set the thermostat to the lowest setting and turn the gas knob to the off position. Wait for around 5 minutes to remove any gas. If you smell any gas, call a local gas supplier or DIY person. If not, then turn gas knob to pilot setting and press and hold it. Light the pilot at a time. Release gas knob and rotate it to on position.
Then turn the thermostat up to make sure the furnace is functioning properly and heating your home. But if pilot light still doesn’t stay on, you may need to replace damaged thermostat or pilot tube. In this case, hire a professional and let him handle the risky job.
FAQs on How To Relight Pilot Light On Furnace
How Much Does it Cost To Repair The Pilot Light On furnace?
On average, repairing pilot lights on a furnace cost around $500 to $1400. It varies depending on the DIYers and the problem with pilot light. If you need to replace whole furnace, it can cost around $2800 to $6800.
Is it Dangerous To Relight A Pilot Light On A Furnace?
Handling a furnace is always a bit risky as it needs to deal with gas and fire. However, homeowners can try to relight pilot lights, particularly by following proper guidelines and precautions. But if you are nervous, hire a professional.
Will The Furnace Work Without A Pilot Light?
Older furnaces require a pilot light to ignite the main burner when thermostat needs heat. However modern furnaces come with an electronic igniter in place of a pilot light. Its sensor works in same way as a thermocouple and also detects flame at burners.
Final Words
Hope you understand how to relight pilot light on furnace and keep the home warm. Though it’s an effective way to keep the furnace functioning, the pilot lights won’t stay on after relighting if there is any internal issue. In this case, hire a local gas supplier to inspect the system thoroughly and fix the issue to keep the pilot light stay lit. It may cost some bucks but will reduce the risk of causing severe injury or explosion.
