Is it safe to relight the pilot light myself?

Yes, on most older standing-pilot furnaces — the manufacturer printed relight instructions on a sticker inside the front access panel exactly so homeowners can do it. The procedure is designed to be safe: the gas valve has a safety hold-down mechanism that won't let unburned gas flow until you confirm the pilot is lit. Two important caveats: (1) if you smell gas at any point during the procedure, stop, leave the house, and call SoCalGas (1-800-427-2200) or 911. (2) If the pilot won't stay lit after 2–3 attempts, stop trying — the underlying problem (usually a thermocouple) is what we're fixing, not the pilot itself.

How much does it cost to replace a thermocouple?

Thermocouples are inexpensive parts ($8–$25 retail) but the labor matters. A professional thermocouple replacement runs $185–$295 in Southern California — flat-rate, including diagnostic confirmation, the part, gas-valve removal and reinstallation, pilot relight, and verification that the safety circuit is working correctly. DIY is possible if you're comfortable working around gas appliances and you can match the thermocouple length and termination type, but most homeowners we see who try DIY end up calling us anyway because of the gas-valve fitting. We carry common thermocouples on every truck.

Does it make sense to replace a 30-year-old furnace just because the pilot won't stay lit?

Often yes. A 30-year-old furnace with a standing pilot is at the end of its expected service life (15–25 years for typical SoCal usage). The thermocouple may be the immediate cause but you're likely also dealing with a marginal heat exchanger, a worn gas valve, oversized gas consumption, and 60% AFUE efficiency vs. modern 95% AFUE. The repair gets you another 6–18 months of operation; replacement gets you 20+ years, much lower gas bills, and qualifies you for TECH Clean California heat-pump rebates if you go electric. We run the math openly. Detail: furnace installation and TECH Clean rebates.

Why does my pilot light keep going out only when it's windy?

Draft. Standing pilot lights need still air around the flame to stay lit and to keep the thermocouple hot. Strong wind events — Santa Ana winds in fall, downslope winds in the Valley — can push down through the flue and blow the pilot out. Long-term fix: have a tech check the flue draft hood and combustion-air intake. Sometimes a properly sized draft diverter is missing or has been damaged. Short-term, you can usually relight after the wind dies down. If it happens repeatedly during the same wind event, the flue or combustion-air setup needs adjustment. Background: Santa Ana winds and HVAC.

Should I switch to a furnace with electronic ignition?

Almost certainly yes if you're replacing the furnace anyway. Electronic ignition (hot-surface igniter or electronic spark) eliminates the standing pilot light entirely — no more lighting it, no more thermocouple to fail, and roughly 7–10% lower gas consumption because you're not burning gas 24/7 to keep a pilot lit. Every modern gas furnace (and every heat pump) uses electronic ignition. The only time we still install standing-pilot equipment is for specialty applications like off-grid cabins. For a regular Southern California home replacement, electronic ignition is now standard.

Troubleshooting

Pilot Light Won’t Stay Lit: Causes, Fixes & When to Call a Pro

Roughly 60% of pilot-light failures we see in older Southern California homes trace back to one $25 part. The part is called a thermocouple, it sits in the pilot flame, and when it stops doing its one job, your furnace stops being able to make heat. The rest of the country mostly retired this whole category of problem with electronic ignition by the year 2000. We are still running these calls every winter in Pasadena, Glendale, Burbank, West LA, and the older parts of the Valley because so much SoCal housing stock still has standing-pilot furnaces from the 1980s.

If you woke up this morning, set the thermostat to 70°F, and the house is still 52°F two hours later, this guide is for you.

How a standing pilot is supposed to work

A standing pilot is a small gas flame that burns continuously inside the furnace. When the thermostat calls for heat, the main gas valve opens, fresh gas hits the pilot flame, and the burners ignite off it.

What keeps the pilot lit when nobody is watching is a small probe called a thermocouple. The flame heats one end of it, which generates a tiny voltage (around 30 millivolts). That voltage holds a magnetic safety valve open inside the gas valve assembly. If the pilot goes out, the thermocouple cools, the voltage drops to zero, and the safety valve slams shut, killing all gas flow. That is why an unlit pilot does not mean your house is filling with gas. The safety system is doing exactly what it should.

Almost every "pilot won’t stay lit" call we run traces back to either the thermocouple or something blowing the pilot out faster than the safety can hold it.

Carbon on the thermocouple tip

This is the cause behind 60 to 70% of the pilot calls I run. Over years of continuous burning, the tip of the thermocouple builds up a thin crust of carbon and oxidation. That crust insulates the metal from the flame. The probe no longer reaches the temperature it needs to generate enough millivolts. The pilot lights, runs for 30 to 60 seconds while you hold the reset button, and the moment you let go, the safety valve closes and everything dies.

You can usually clean it. Gas valve to OFF. Wait 5 minutes for residual gas to clear. With a piece of fine emery cloth or 220-grit sandpaper, gently scuff the tip of the thermocouple (the small metal probe sticking into the pilot flame). Do not bend it, do not move it. Wipe it down with a dry cloth, restore gas, relight per the sticker inside the access panel. Stays lit, you are done.

The thermocouple itself is dead

If cleaning did not fix it, the thermocouple has aged out internally. Service life is typically 5 to 15 years. Coastal homes burn through them faster (corrosion from salt air); inland systems last longer. The probe just stops generating enough voltage even with a clean surface.

The part costs $8 to $25 retail. Replacement runs $185 to $295 fixed-price in SoCal: shutting off gas, removing the gas-valve fitting, swapping the probe, reassembling, relighting, and verifying the safety circuit holds. We carry common thermocouples on every truck. DIY is possible if you are comfortable around gas appliances, but match the length and termination type or you end up calling us anyway. Detail: furnace repair.

Gas supply issues

Less common but worth a 30-second check. Low gas pressure produces a weak pilot flame that cannot heat a perfectly fine thermocouple to operating temperature. Three quick things:

Test other gas appliances. If your stove takes forever to boil water and the water heater is sluggish, the supply itself is the problem, that is a SoCalGas call (1-800-427-2200), not an HVAC contractor call
Confirm the gas shutoff valve at the furnace is fully open. They get bumped during garage and closet cleaning more often than you would think
If SoCalGas did work in your neighborhood recently, sometimes air enters the line. Pilots can be flaky for a day until the air purges through

Wind blowing the pilot out

If the pilot stays lit on still days but blows out the moment a wind event hits, you have a draft problem, not a thermocouple problem. We see this every fall during Santa Ana winds and during the downslope events that hit Pasadena, Glendale, Burbank, and the Conejo Valley. Wind pushes back down through the flue and snuffs out the pilot from above.

Real fix: a tech inspects the flue draft hood, the combustion-air intake, and the chimney. Sometimes the draft diverter is missing or damaged, sometimes the chimney needs a cap or a fresh screen. Short-term you can relight once the wind dies. Long-term it needs a proper draft check.

Spider webs in the pilot orifice

The pilot orifice is a tiny brass fitting that meters gas to the pilot flame. Spider webs, dust, and corrosion can partially block it. Symptoms: weak yellow pilot flame instead of a strong blue one, and the same not-enough-heat-to-the-thermocouple result.

Tech-only fix. Cleaning the orifice properly involves pulling the pilot assembly, clearing the bore with a fine wire (a drill bit changes the bore size and the gas metering with it), and reassembling. $185 to $295, often combined with a thermocouple replacement on older furnaces since you are already in there.

How to relight a pilot safely

Always check the relight sticker inside your access panel for your specific model. General procedure:

Thermostat to its lowest setting or OFF
Open the access panel. Find the gas valve, three positions, OFF, PILOT, ON
Valve to OFF. Wait 5 minutes for residual gas to clear. If you smell gas at any point, stop, leave the house, call SoCalGas or 911 from outside
Valve to PILOT
Press and hold the red reset button next to the valve while igniting the pilot with a long-reach lighter or match
Once the pilot is lit, keep holding the reset button for 30 to 60 seconds. The thermocouple needs that time to come up to operating temperature
Release the button. If the pilot stays lit, turn the valve to ON, set the thermostat to HEAT. Burners should fire within 1 to 2 minutes
If the pilot dies the second you release the button, you have a thermocouple problem (clean it or replace it)

Gas smell means stop everything

This is the most important paragraph on this page. If at any point during this procedure you smell a strong, persistent gas odor:

Leave the house immediately
Do not flip light switches. Do not start a car in the attached garage. Do not use a phone inside
From a neighbor’s house or outdoors, call SoCalGas at 1-800-427-2200 or 911
Do not go back in until utility or fire crews clear the building

A faint, brief gas smell for a few seconds during the relight is normal. A persistent strong smell anywhere in the house is an emergency. Once cleared, we can come out 24/7 to diagnose, emergency HVAC.

The case for retiring the standing pilot entirely

Every gas furnace built since the late 1990s uses electronic ignition, either a hot-surface igniter (a glowing ceramic element) or a direct-spark setup. No pilot, no thermocouple, no relight ritual. Benefits: 7 to 10% lower gas consumption (the pilot is not burning 24/7 to keep itself lit), no pilot to fail, simpler service.

Honest math on a 25-plus-year-old furnace with recurring pilot problems: a $250 thermocouple replacement every 18 months is not a maintenance schedule, it is a slow-motion replacement bill. The other moving parts on equipment that age (gas valve, heat exchanger, blower bearings) are heading the same direction. Replacement options run $4,800 to $9,500 for a same-fuel gas furnace, or $5,000 to $12,000 for a heat-pump conversion before the TECH Clean California rebate ($3,000 to $8,000) comes off the top. We quote both side-by-side so you see the operating-cost difference before deciding. Detail: furnace installation, heat pump, TECH Clean rebates.

Pilot won’t stay lit after a relight?

Call Venta Heating & Air at (424) 766-1020, same-day service across Southern California. CSLB #1138898 (C-20).