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Is It Dangerous If the Pilot Light Goes Out? Honest Plumber's Answer
Is It Dangerous If the Pilot Light Goes Out? Honest Plumber's Answer, a Prime Plumbing & Gasfitting plain-English guide to is it dangerous if the pilot light goes out for Melbourne homeowners. Below we cover what works, what doesn't, and when to call a licensed plumber.
Quick answer: On modern Australian gas appliances, a pilot light going out is usually not dangerous because the appliance has a built-in flame-failure device (a thermocouple or thermopile) that automatically shuts off the gas supply when the pilot extinguishes. On very old appliances without that device, a pilot going out CAN be dangerous because gas keeps flowing. If you smell gas after the pilot goes out, evacuate and call 000. If there's no smell, the appliance has likely cut itself off safely, and the question becomes "why did it go out and how do I get it relit?"
If your hot water unit's pilot light has gone out, or your old gas heater's pilot won't stay lit, the first thing you want to know is whether you're in immediate danger. Honest answer: usually no, on a modern Australian appliance. But there's nuance, and there ARE cases where it matters.
If you smell gas
Pilot out + no smell of gas = appliance has likely cut itself off safely. Pilot out + you can smell gas = potential leak, treat as urgent.
If you smell gas:
- Don't try to relight the pilot: that's an ignition source
- Turn off gas at the appliance's isolation valve (usually a small lever on the gas line near the appliance)
- Open windows and doors to ventilate
- Don't use electrical switches or phones inside the building
- Call from outside: emergency gas hotline 000, or 000 for a major leak
The rest of this article assumes there's no gas smell. If there is, deal with the safety issue first.
How a modern Australian gas appliance handles a pilot going out
Modern Australian gas appliances (anything built since the 1990s, generally) have a flame-failure device (FFD): a small temperature sensor that sits in the pilot flame. The two common types are:
Thermocouple
A small metal probe in the pilot flame. The flame heats it, generating a tiny voltage that holds open a magnetic gas valve. When the flame goes out, the probe cools, voltage drops, and the magnetic valve closes, cutting gas to the pilot. Without the probe being hot, gas can't flow to the pilot. That's the safety feature.
Thermopile
Same principle but generates more voltage and is used on appliances that need to power additional valves (e.g. main burner valve plus pilot valve). Same safety behaviour: cools, voltage drops, valves close.
Both devices typically respond within 30-60 seconds of the flame going out. After that, gas to the pilot is cut and you can't accidentally release gas just by leaving the appliance "on" with the pilot dead.
Old appliances without flame-failure devices
Pre-1990s gas appliances (some pre-1980s especially) may NOT have flame-failure devices, or may have ones that have failed. On these:
- Pilot going out can leave the gas supply open
- Gas accumulates in the appliance and surrounding area
- Re-ignition (from another flame, electrical switch, etc.) can cause an explosion or fire
If you have an old gas heater (especially an unflued portable one), an old gas oven, or a vintage hot water unit, the absence of a flame-failure device is a serious safety concern: not just because of pilot issues but because Australian regulations have evolved significantly. Most old appliances without FFDs should be replaced.
We see these occasionally on older Toorak / Camberwell / Hawthorn properties where heritage homes still have decades-old gas heating. We always recommend replacement on these, normally a heat pump is the better long-term option anyway.
Why your pilot keeps going out, common causes
Assuming you're on a modern appliance with a working FFD (no immediate danger), the question becomes: why did the pilot go out and what now?
1. Failed thermocouple or thermopile
The most common cause. The probe degrades over years from being in the flame, the metal corrodes, the voltage output drops below the threshold, and the gas valve closes mid-cycle even when the flame is still lit.
Real example: On a recent Caulfield callout, the homeowner's hot water unit pilot wouldn't stay lit, it would light, hold for a few seconds, then go out as soon as they released the manual ignition button. Diagnosis: thermocouple voltage 9 mV, well below the 18-25 mV the magnetic valve needs. Replacement thermocouple, 30 minutes on-site, problem solved.
2. Dirty pilot orifice
The pilot's gas comes through a tiny precision orifice. Dust, lint and spider webs (genuine cause in Melbourne, Australian funnel-spider webs love warm gas appliances) can partially block the orifice and starve the flame. The flame becomes weak, doesn't heat the thermocouple enough, and the FFD cuts off.
Cleaning the orifice is a job for a Type A gasfitter, it involves disassembling the pilot assembly.
3. Pilot tube partially blocked
Same as the orifice issue but further upstream. Less common but happens on older appliances.
4. Drafts blowing the pilot out
A pilot in a position exposed to drafts (hot water unit in a side passage with wind funnel, or an old wall furnace near a door) can be physically blown out by wind. The FFD will cut off gas safely, but the pilot won't relight automatically. Solution: shield or relocate (sometimes requires a Type A gasfitter to safely modify).
5. Gas pressure issues
If gas pressure to the appliance is too low, the pilot won't stay lit. Causes include a partially blocked regulator, a too-small gas line for the appliance load, or distributor-side issues. Less common but worth checking on multi-appliance properties where adding a new high-load appliance (continuous-flow hot water, large oven) can starve other appliances.
6. End-of-life unit
Hot water units past 12-15 years often have multiple aging components. The pilot going out is sometimes the first symptom of broader end-of-life, and a single component repair might be a band-aid. We're honest on the quote: if the unit is past 15 years and the thermocouple has gone, replacement is typically the better long-term call. See our hot water replacement page if that applies.
Book a gasfitter
Pilot light gone out and won't stay lit? Call 0475 407 670 or send the appliance make + model + your address through the contact form.
- BPC #103414: Building and Plumbing Commission licence
- Type A gasfitting endorsement for gas appliance work, held on the BPC licence
- 4.8 stars on Google
- Fixed-price written quote before any work
- Certificate of Compliance lodged with ESV where the work requires one
Related: Can a plumber fix a gas leak? · Gas Leak Detection Melbourne · Gas Fitter Melbourne · Hot Water Replacement Melbourne
About the author
Alister Williams is the founder and lead plumber of Prime Plumbing & Gasfitting. He's been licensed under BPC #103414 for over a decade, holds Type A Gasfitter endorsement with Energy Safe Victoria, and is a member of the Master Plumbers Association of Victoria.
How to safely relight a pilot
Most modern hot water units, gas heaters, and gas log fires have a piezo igniter with a manual relight procedure. The instructions are often printed on a label on the appliance itself, read those FIRST. The general procedure:
- Turn the gas control knob to OFF and wait 5 minutes for any residual gas to clear
- Turn the knob to PILOT
- Press and hold the gas valve down (this lets gas flow to the pilot)
- Press the piezo ignition button to spark
- Once lit, hold the gas valve down for 30-60 seconds (lets the thermocouple heat up)
- Release the valve. If pilot stays lit, turn the knob to ON.
- If pilot doesn't stay lit, repeat once. If still doesn't hold after a second attempt, stop and book a gasfitter: repeated relight attempts on a faulty thermocouple won't fix it.
Don't keep trying to relight a pilot that won't stay lit. The FFD is doing its job, the issue needs diagnosis, not more attempts.
Service area
Prime Plumbing & Gasfitting services gas appliance repair and pilot-light callouts across Melbourne's eastern, south-eastern, inner-east and bayside suburbs. See all suburbs we service
When to call a Type A gasfitter
Book a service visit if:
We diagnose, quote in writing, and fix or replace as appropriate.
Frequently asked questions
On a modern appliance with a working FFD: no. The gas has been cut off automatically. The hot water tank may have cooled (no hot water) but there's no ongoing hazard.
Not advisable. Each relight attempt is a small ignition event. If something IS wrong (which is why the pilot keeps going out), you're repeatedly creating ignition opportunities while gas may be slightly elevated in the area. Two attempts max, then book a gasfitter.
Yes, each appliance is independent and has its own FFD. The other appliances aren't affected by one appliance's pilot going out.
Depends on the cause. Thermocouple replacement is the most common fix and is a small visit. Pilot orifice cleaning or pilot assembly replacement is a similar scope. If the diagnosis turns up the unit is at end-of-life, replacement is more involved, see hot water replacement for that path.
Anything involving gas, including disassembling a pilot assembly, requires a Type A gasfitter under Victorian law. Even if you got the orifice clean, you'd need to pressure-test the gas line afterwards (a Type A gasfitter task with a Certificate of Compliance lodged with ESV). Not DIY territory.
Don't keep using it. Old appliances without FFDs are a recognised safety risk (see Energy Safe Victoria's gas safety advice). Most are also long past their service life, and the running cost of an old gas heater is generally higher than a modern alternative. Get it replaced.
Cold air pressure changes plus increased appliance use plus more drafts through doors and chimneys add up. Old appliances are more sensitive to all three. If you've got a recurring winter pilot problem, it's worth a service visit before the cold sets in properly.
Before You Book
A quick checklist to share with your plumber when you book:
- When did the issue start?
- Is it isolated to one fixture or multiple areas?
- Are there any visible leaks, smells or unusual sounds?
- Have you turned off the relevant isolation valve?
If you're unsure, Prime Plumbing & Gasfitting can inspect the issue and explain the options before any work starts. Call 0475 407 670 or request a quote online.
