An outdoor gas heater flame that keeps blowing out is one of the most common complaints NZ homeowners have — especially during our blustery spring and autumn evenings. The good news is that most causes are straightforward to identify, and some are easy to fix yourself. However, because gas appliances are involved, it's important to know where the DIY boundary is and when a licensed gasfitter must step in.
The Most Common Reasons Your Flame Keeps Going Out
There are several likely culprits, and it helps to work through them one at a time.
1. Wind Is Extinguishing the Flame
This is the single most common cause for outdoor heaters in New Zealand. Our coastal and elevated locations mean wind can be unpredictable and gusty. Most portable outdoor gas heaters are not designed to operate in winds above around 15–20 km/h. If the flame flickers and dies whenever a gust hits, wind is almost certainly your problem.
What you can do:
- Reposition the heater in a more sheltered spot — against a wall, fence, or under a pergola.
- Use a purpose-built outdoor heater windshield or screen (available at Bunnings or Mitre 10).
- Check your heater's manual for its rated wind tolerance.
2. A Faulty or Dirty Thermocouple
The thermocouple is a small safety sensor that detects whether the pilot flame is burning. If it senses no heat, it automatically shuts off the gas supply — which is exactly what it's designed to do. Over time, thermocouples can become coated in carbon deposits, corroded, or simply wear out.
Signs of a thermocouple problem include:
- The pilot lights but the main flame won't stay on when you release the ignition button.
- The heater cuts out within a few seconds of lighting.
What you can do: Gently clean the thermocouple tip with fine steel wool or a soft cloth to remove carbon build-up. If cleaning doesn't help, the thermocouple likely needs replacing — this is a relatively inexpensive part but should be replaced by a licensed gasfitter to ensure it's fitted correctly and safely.
3. Low Gas Pressure or an Empty Cylinder
If your LPG cylinder is running low, gas pressure can drop below the level needed to keep the burner alight. Cold weather also reduces the pressure in LPG cylinders, which is a real factor in NZ winters.
What you can do:
- Shake the cylinder gently — if it sounds nearly empty, swap it out.
- In cold weather, try moving the cylinder to a slightly warmer (but still well-ventilated) spot. Never use artificial heat to warm a gas cylinder.
- Check that the regulator (the fitting between the cylinder valve and the hose) is the correct type for your heater. NZ LPG appliances use a standard low-pressure regulator; using the wrong one can cause pressure issues.
4. A Blocked or Dirty Burner
Insects, spider webs, dust, and debris can partially block the burner jets or the pilot assembly, causing an uneven or weak flame that's easily extinguished.
What you can do:
- Turn off the gas completely at the cylinder and allow the heater to cool.
- Use a soft brush or compressed air to clear debris from around the burner and pilot area.
- Avoid using water or liquid cleaners inside the burner assembly.
5. A Damaged or Perished Gas Hose
Cracks, kinks, or perished rubber in the gas hose can cause pressure drops that starve the burner of fuel. Hoses should be inspected regularly — WorkSafe NZ recommends replacing LPG hoses that show any signs of cracking, brittleness, or damage.
What you can do: Visually inspect the hose and connections. If you spot any damage, do not use the heater — replace the hose before operating it again. Hose replacement on a portable outdoor heater is generally a DIY task, but if you're unsure, have a gasfitter check it.
6. Regulator Fault
Regulators can fail or freeze up (especially in cold, damp NZ conditions), causing inconsistent gas delivery. A faulty regulator may need to be replaced.
A Quick Diagnostic Table
| Symptom | Most Likely Cause | DIY Fix? |
|---|---|---|
| Flame dies in gusts | Wind | Yes — reposition or shield |
| Pilot lights, main flame won't hold | Thermocouple fault | Clean yourself; replace via gasfitter |
| Weak flame, cylinder feels light | Low gas / cold cylinder | Yes — swap cylinder |
| Flame sputters and dies | Blocked burner or jets | Yes — clean carefully |
| Hissing or smell of gas | Hose or connection leak | No — call a gasfitter immediately |
Safety First — What to Do If You Smell Gas
If you smell gas at any point:
- Turn off the gas at the cylinder valve immediately.
- Move away from the heater and do not use any ignition sources.
- Ventilate the area.
- Call a licensed gasfitter before using the appliance again.
Never attempt to repair gas valves, regulators, or internal gas components yourself. Under NZ trade licensing rules, work on gas fittings must be carried out by a gasfitter registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB).
When to Call a Professional
You should contact a licensed gasfitter if:
- Cleaning the thermocouple doesn't resolve the issue and it needs replacing.
- You suspect a regulator fault.
- You can smell gas or find a leak.
- The heater is a fixed or plumbed-in outdoor gas heater — any work on fixed gas installations is restricted work under NZ law and must be done by a PGDB-registered gasfitter.
- You're unsure about any aspect of the diagnosis.
A qualified local gasfitter can inspect your heater, test gas pressure, and replace faulty components safely. You can find licensed gasfitters in your area on tradedirectory.co.nz.
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