What a bayonet does
The heater's hose clicks into the bayonet, and a valve inside opens only when the plug is seated. Unplug it, and the valve closes and the dust cap goes back on.
Outdoors, a bayonet lets a natural gas barbecue run straight off the house supply instead of a bottle. The barbecue has to be made or converted for natural gas first.
Signs a bayonet needs a gas fitter
- A gas smell at the bayonet, plugged in or not.
- The heater plug won't click in, or pops back out.
- A hissing sound when the heater is connected.
- A cracked hose on the heater, or a loose or damaged wall plate.
- A bayonet where the heater can't safely sit, such as behind a door or beside a curtain.
What a gas fitter will do
A gas fitter will take a branch off the nearest gas line, run pipe to where you want the bayonet, and fix the outlet to the wall or floor. They leak-test the new pipe, plug in your heater or barbecue, and check it lights and burns cleanly.
They'll also look at whether the heater suits the room. Some heaters need a flue or a certain amount of fresh air, and the heater's manual sets out what it needs.
What changes the job
How far the bayonet is from an existing gas pipe, and the route between them. A timber floor with room underneath is simpler than a slab or a double brick wall. Indoor or outdoor, how many bayonets you want, and whether the heater or barbecue needs converting all change it too.
Your part, and the fitter's
You can
- Plug the heater in and out the way its manual shows, with the heater off.
- Keep the dust cap on when nothing is connected.
- Check the heater's hose for cracks before winter.
- Pick a spot where the heater has clear space around it.
Leave to a licensed plumber
- Fitting a new bayonet, or moving one.
- Repairing a bayonet that leaks or won't hold the plug.
- Converting a heater or barbecue to your gas type.
- Running gas pipe to an outdoor kitchen or barbecue area.
Licences and rules
Gas pipe work needs a gas licence. The ACT, for example, licenses gasfitters in classes of their own: advanced, general, journeyperson and LPG, plus restricted automotive classes. Ask the fitter which licence they hold, then check it on your state's register: see checking a licence.
In Victoria, the Government said in 2025 that "There are no changes to heating for owner occupiers," so a gas heater on a bayonet in your own home isn't touched by the 2027 hot water rule.
Questions to ask the gas fitter
- Can the bayonet go where I'll actually use the heater?
- Is my heater suitable for this room, and does it need a flue?
- Can my barbecue run on natural gas, or does it need converting?
- Will you test the bayonet with the heater plugged in?
What we would do
Put the bayonet where you'll use the heater, not where the pipe is easiest. A heater stretched across a room on its hose, or jammed beside a curtain, is how bayonets get misused. If you're unsure about the heater itself, ask for it to be checked on the same visit: a licensed gas fitter can tell you whether it's safe to keep.