What to Do When Your Water Heater Pilot Light Keeps Going Out

A gas water heater that repeatedly loses its pilot flame is more than an inconvenience. It can leave your household without hot water, increase the risk of unsafe combustion, and point to a fault that will worsen if ignored. A pilot light may go out because of a simple draught, but the cause can also involve the thermocouple, gas supply, burner assembly, or flue.

This guide explains safe checks for homeowners, when relighting is reasonable, and when a licensed professional should take over. The advice is useful for Australian homes and rental properties, where natural gas and LPG appliances are common in cities such as Sydney, Melbourne, Brisbane, Perth, and Adelaide.

Start With Gas Safety

If you smell rotten eggs, hear hissing near the water heater, or suspect a gas leak, do not try to relight the pilot. Avoid electrical switches, flames, cigarettes, and anything that could create a spark. If it is safe, turn off the gas supply at the appliance or meter, leave the property, and contact your gas distributor or emergency service from outside.

Australian gas systems use both mains natural gas and bottled LPG, and the correct response can vary depending on the installation. LPG is heavier than air and may collect in low areas, while natural gas generally rises. Never attempt to test for a leak with a match. A licensed gasfitter should inspect the appliance and pipework.

Carbon monoxide is another serious concern. It is colourless and has no reliable smell, and poor combustion or a blocked flue can allow it to build up indoors. Headaches, dizziness, nausea, unusual tiredness, or confusion require immediate fresh air and urgent medical attention. A carbon monoxide alarm provides an extra layer of protection, but it does not replace professional servicing.

Check The Manufacturer’s Relighting Instructions

If there is no smell of gas and the appliance appears intact, look for the manufacturer’s lighting label. It is usually found behind the lower access panel or on the front of the water heater. Older storage units often have a control knob marked “off”, “pilot”, and “on”, along with a separate ignition button or viewing window.

Turn the control to “off” and wait for the period stated on the label, commonly five minutes. This allows unburned gas to clear. Then select “pilot”, press and hold the control, and use the built-in igniter if provided. Some older models require a long gas lighter, but only use one if the instructions specifically permit it and the burner area can be accessed safely.

Keep holding the control for the specified time after the flame appears. This allows the safety sensor to heat up. Release it slowly and watch the pilot through the viewing window. If the flame stays lit, turn the control to “on” and check that the main burner starts normally.

Do not keep repeating the process if the flame goes out again. Two or three failed attempts are enough to stop and arrange a service call. Never bypass the safety control, wedge the button down, or alter the gas valve to keep the heater operating.

Understand Why The Flame Keeps Going Out

The thermocouple is one of the most common causes of a pilot that lights but will not remain lit. This small safety device sits in the pilot flame and generates a signal when heated. If the flame is too weak, the thermocouple is dirty, incorrectly positioned, worn out, or unable to produce enough voltage, the gas valve shuts off as designed.

A healthy pilot flame is generally steady and blue, with enough contact around the thermocouple tip. A yellow, flickering, or unusually small flame can indicate a blocked pilot orifice, low gas pressure, contamination, or poor adjustment. Cleaning and testing these parts requires care, especially because opening the gas control system without the right knowledge can create a dangerous fault.

Air movement can also extinguish the pilot. Strong draughts from an open door, roof cavity, exhaust fan, or nearby ventilation opening may disturb the flame. Do not seal or block permanent vents to solve the problem. Gas appliances need sufficient combustion air, and changing ventilation can create carbon monoxide hazards.

A damaged burner compartment, defective gas control valve, or failing ignition system may produce similar symptoms. If the pilot stays on for minutes or hours and then disappears, the thermocouple or gas valve deserves particular attention. If the entire appliance shuts down during windy weather, the flue and ventilation system should be checked.

Inspect The Area Without Opening Gas Components

Before calling a technician, you can make a visual inspection from outside the appliance. Look for water around the base, soot or black staining, rust, damaged insulation, unusual condensation, or debris around the air intake and flue termination. Any soot, scorching, or signs of overheating should be treated as a reason to switch the unit off.

Keep boxes, cleaning products, laundry, garden equipment, and other combustible materials away from the heater. Outdoor gas storage heaters still require clearances around the burner and flue. In Australian homes, compact laundries, garages, and under-house installations can make it easy for belongings to restrict airflow or conceal a developing leak.

Do not remove sealed covers or reach into the burner chamber. Do not spray insecticide, compressed air, water, or cleaning chemicals into the pilot assembly. Spiders and insects can sometimes build webs in gas appliance components, particularly in warmer areas such as Brisbane or Perth, but clearing an internal obstruction is a job for a licensed gasfitter.

Also check whether another gas appliance is working. If the cooktop or central heating system has lost gas at the same time, the issue may involve the meter, regulator, supply line, or LPG cylinder rather than the water heater itself. A shared supply problem needs prompt attention from the gas provider or a qualified professional.

Know When The Flue Or Drain Is Involved

A pilot light can go out because combustion gases cannot leave the building properly. Birds’ nests, leaves, corrosion, building work, or a displaced flue can obstruct the exhaust path. A downdraught may push combustion products back toward the burner and activate a safety shutdown. Never operate the appliance with a disconnected, damaged, or visibly blocked flue.

Water problems can create a separate set of warning signs. A leaking storage tank, pressure relief valve, or tempering valve may leave water near the heater and eventually affect surrounding floors, walls, or cabinetry. In older Australian homes, a slow leak can travel beneath tiled surfaces before it becomes obvious.

If the heater’s discharge pipe releases water continuously, do not cap or block it. The pressure relief system is designed to protect the tank. A plumber should determine whether the valve is faulty, the water pressure is too high, or the cylinder is nearing the end of its service life. Where a leak is accompanied by a blocked floor waste or overflowing drain, arrange prompt sewer and drain service to limit property damage.

Consider The Age And Type Of Heater

Many Australian properties still have older gas storage water heaters, while newer homes may use instantaneous gas units, electric heat pumps, or solar systems with gas or electric boosting. A visible pilot light is most often associated with an older storage model. Instantaneous units typically use electronic ignition and will display a fault code rather than a standing pilot flame.

Check the data plate for the brand, model, gas type, and approximate installation date. Rheem, Rinnai, Vulcan, Bosch, and Dux units may use different ignition procedures and replacement components. A part that suits a natural-gas model may be unsafe in an LPG appliance, even if it looks identical.

Age matters when deciding whether repair is sensible. A thermocouple replacement may be straightforward, but repeated control-valve, tank, flue, and burner faults can make replacement more economical. Energy efficiency, household size, available space, and local rebates can influence the choice between a new gas storage unit, instantaneous system, heat pump, or solar-compatible setup.

A professional should confirm that the replacement complies with current Australian requirements, including correct gas type, clearances, ventilation, temperature control, and discharge pipework. In homes with young children, a correctly adjusted tempering valve helps reduce the risk of scalding at taps.

Arrange The Right Level Of Professional Help

Call a licensed plumber or gasfitter when the pilot will not stay lit after one careful relighting attempt, when the flame is yellow or unstable, or when the appliance repeatedly shuts down. Professional testing can identify a weak thermocouple, blocked injector, low gas pressure, defective gas valve, faulty thermostat, or flue problem without relying on guesswork.

Treat the issue as urgent if there is a gas smell, visible smoke, soot, a carbon monoxide alarm, a leaking tank, or water near electrical equipment. A complete loss of hot water may be inconvenient, while an active gas or water leak can threaten health and cause substantial damage. For properties in Los Angeles or Phoenix, emergency plumbing guidance can help distinguish an immediate call-out from a routine booking.

When arranging service in Australia, ask whether the person attending holds the required state or territory licence for gas work. Licensing rules differ between jurisdictions, and gas appliances should not be repaired by an unqualified handyman. Request a clear explanation of the diagnosis, parts, labour, safety checks, and whether the quoted price includes testing and recommissioning.

Keep the model and serial number available, along with details about when the fault occurs. Tell the technician whether the pilot goes out immediately, after the main burner starts, during windy conditions, or after the heater has run for several hours. These details can shorten the diagnostic process and reduce unnecessary part replacements.

Prevent Repeat Pilot Failures

Annual servicing is a sensible schedule for many gas water heaters, particularly older units, appliances installed outdoors, and systems exposed to dust, salt air, insects, or severe weather. Coastal homes around Sydney, Melbourne, and Adelaide may experience corrosion, while dusty conditions around western and inland suburbs can affect burners and ventilation openings.

Keep the heater’s clearances unobstructed and check visible vents and flue outlets periodically without dismantling anything. Arrange an inspection after building work, roof repairs, flooding, or a major storm. A change in the pilot flame, burner noise, hot-water temperature, or gas consumption should be investigated rather than ignored.

A household can also reduce stress on the system by avoiding excessive temperature adjustments and ensuring that hot-water outlets are not left running unnecessarily. If the unit is approaching the end of its expected life, plan a replacement before a winter breakdown or holiday period creates an emergency.

The safest response to a repeatedly extinguished pilot is to treat it as a warning from the appliance. Relight it only according to the instructions, stop if it fails again, and have the gas supply, combustion, safety controls, and flue assessed by a qualified professional.

For 24/7 emergency plumbing, water heater, leak detection, and restoration support in the Los Angeles and Phoenix metropolitan areas, contact The Twin Plumbers. The family-run team serves residential and commercial properties, provides free estimates, and uses transparent pricing to help you restore safe hot water and protect your property from related damage.