If your outdoor BBQ isn't performing well — weak flames, uneven heat, or slow ignition — low gas pressure is often the culprit. However, adjusting gas pressure in New Zealand is largely restricted work under the Gas Act 1992, meaning most of it must be carried out by a licensed gasfitter. Understanding what you can and cannot legally do yourself is essential for both safety and compliance.
Why Gas Pressure Matters for Your BBQ
Gas appliances are designed to operate within a specific pressure range. Most LPG (liquefied petroleum gas) BBQs in New Zealand are designed to run at 2.75 kPa at the appliance inlet, regulated down from the much higher pressure stored in the cylinder. If pressure is too low, you get poor combustion, weak burners, and frustrating cooking results. If it's too high, you risk appliance damage, gas leaks, or fire.
Natural gas BBQ connections operate at different pressures again, typically around 1.0–1.13 kPa at the appliance, and these are supplied via your home's reticulated gas system — a network that is entirely the domain of licensed professionals.
What Homeowners Can Legally Do Themselves
Before assuming you need a pressure adjustment, check the basics — these are things you can safely do yourself:
- Check your LPG cylinder level. A near-empty cylinder will deliver lower pressure. Swap it for a full one and test again.
- Inspect the regulator connection. Make sure the regulator is firmly attached to the cylinder valve. A loose connection causes pressure drop.
- Check for kinked or damaged hoses. A kinked hose restricts gas flow and mimics low pressure. Replace any hose that is cracked, kinked, or perished.
- Clean burner ports. Blocked burner holes reduce flame performance regardless of pressure. Use a small brush or pin to clear debris.
- Check the BBQ's built-in regulator. Most LPG BBQs come with a factory-set regulator attached to the hose. If this regulator is faulty or aged, it may be under-delivering pressure. You can replace a BBQ hose-and-regulator assembly yourself, provided you use an approved assembly designed for your appliance and do not alter any fixed gas installation.
Important: Replacing a hose-and-regulator assembly that connects directly to a portable LPG cylinder (i.e., not a fixed piped installation) is generally considered acceptable for a competent homeowner. Always buy a compliant assembly from a reputable supplier such as Bunnings or Mitre 10, and ensure it carries the appropriate NZ/Australian approval markings.
What Is Restricted Work — Do Not DIY
Under the Gas Act 1992 and its regulations, the following work is restricted to licensed gasfitters only:
- Adjusting or replacing a fixed gas regulator — this includes any regulator that is part of a piped installation (e.g., a natural gas or LPG bulk-tank system plumbed to your home or outdoor area).
- Altering gas pipework or fittings in a fixed installation.
- Installing or modifying a fixed outdoor BBQ gas point (the bayonet fitting or isolation valve on your wall or deck).
- Changing the supply pressure at the meter or primary regulator for natural gas.
- Any work on natural gas reticulation, full stop.
Attempting this work yourself is illegal, potentially invalidates your home insurance, and — most critically — puts lives at risk. Gas leaks and incorrect pressures can cause fires, explosions, and carbon monoxide hazards.
You can verify a tradesperson's licence on the Plumbers, Gasfitters and Drainlayers Board (PGDB) website before hiring.
Diagnosing the Real Problem
Before calling a gasfitter, it helps to narrow down the issue:
| Symptom | Likely Cause | Who Fixes It |
|---|---|---|
| Weak flame on full LPG cylinder | Faulty hose/regulator assembly | Homeowner (replace assembly) |
| Flame cuts out in cold weather | LPG cylinder freezing (common in NZ winters) | Homeowner (warm cylinder, check fill level) |
| Low pressure on natural gas BBQ point | Fixed regulator or supply issue | Licensed gasfitter |
| Smell of gas near connection | Leak in hose, fitting, or pipework | Stop use immediately, call gasfitter |
| Pressure fine but burners uneven | Blocked burner ports | Homeowner (clean burners) |
If you smell gas at any point, turn off the cylinder or gas supply immediately, ventilate the area, do not operate any electrical switches, and call a licensed gasfitter or your gas supplier.
Choosing the Right Regulator Assembly
If you're replacing a portable LPG hose-and-regulator assembly yourself, look for:
- Compliance markings — the assembly should reference AS/NZS 1869 (hose) and AS/NZS 4161 (regulators) or equivalent approved standards.
- Correct outlet pressure — most NZ LPG BBQs require a 2.75 kPa regulator. Check your BBQ's manual.
- Correct thread type — NZ LPG cylinders use a left-hand thread (POL fitting) or a clip-on connection depending on the cylinder type. Match your existing setup.
For guidance on gas safety standards, BRANZ and MBIE Building Performance are useful starting points.
When to Call a Professional
Call a licensed gasfitter if:
- Your BBQ is connected to a fixed piped gas installation (natural gas or bulk LPG).
- You've replaced the hose-and-regulator assembly and still have low pressure.
- You suspect a leak anywhere in the system.
- You want to install a new outdoor gas point or upgrade your supply line.
- You're unsure about any part of the system.
A licensed gasfitter can test your system pressure with calibrated equipment, identify the exact fault, and carry out any restricted work legally and safely. You can find qualified local gasfitters on tradedirectory.co.nz.