Swapping a gas cooktop, heater or hot water unit looks like a simple appliance change, but the gas connection behind it is licensed work for good reason: gas is unforgiving when it is done wrong. Here is what actually happens when a licensed gas fitter does a changeover, and why the paperwork matters.
TL;DR
Connecting a gas appliance to the gas installation is licensed gasfitting work, a separate licence category from plumbing, so it must be done by a licensed gas fitter, not a handyman or a plumbing-only operator. Every gas job ends with a certificate: a certificate of compliance for natural gas, or a certificate of inspection for bottled LPG. Natural gas and LPG are not interchangeable without a proper conversion.
Why does it have to be a licensed gas fitter?
In NSW you need a licence for any plumbing, draining or gasfitting work, whatever the job costs, and you have to be licensed in each category you work in. Gasfitting is its own category, separate from plumbing. It covers connecting a gas appliance to the gas installation (other than plugging it into a gas outlet socket, the bayonet point), and installing or repairing a flue. The NSW Government’s advice on using a gasfitter is to use a licensed gasfitter for any repair or renovation involving gas, including relocating or replacing a gas appliance.
That catches a lot of people out: plenty of plumbers, and every handyman, are not legally allowed to connect a gas appliance. The reason is straightforward, an undetected gas leak or a badly flued heater is a fire, explosion or carbon-monoxide risk, so the work is tightly controlled. Josh holds both the plumbing and the gas fitting licence: you get one tradesperson who can legally do the whole job and certify it.
What does a changeover actually involve?
A proper changeover is more than unplugging the old unit and connecting the new one. Depending on the appliance, the job covers:
- Isolating and removing the old appliance safely, capping the line if needed.
- Checking the gas supply and pressure is right for the new appliance, and that the line and any regulator suit its demand.
- Connecting the new appliance with the correct fittings, then leak-testing the connection.
- Flueing, for a heater or some hot water units, making sure combustion gases vent safely outside.
- Commissioning: lighting it, checking it runs cleanly, and on heaters, checking for carbon monoxide.
- Issuing the certificate for the work.
What certificate should I get?
After any work involving gas, the licensed gas fitter must give you a certificate of compliance for network (natural) gas, or a certificate of inspection for bottled gas. It confirms a licensed gas fitter did the work and that it meets the relevant standards, which for gas installations is AS/NZS 5601. It must show the licensee’s name and licence number.
Keep it. It is your proof the work was done and certified by a licensed gas fitter, it protects you against faulty work, and an insurer or a settlement agent may ask to see it. A cheap cash job with no certificate leaves you with none of that.
Can LPG and natural gas appliances be swapped?
Not without a conversion. The two gases reach the house differently and need different settings inside the appliance.
| Natural gas | LPG | |
|---|---|---|
| How it is supplied | Piped network to the street | Refillable cylinders (bottles) |
| Appliance setup | Its own pressure and injectors | Different pressure and injectors |
| Certificate after gas work | Certificate of compliance | Certificate of inspection |
An appliance set up for one will not run safely on the other. If you are moving house, switching supply, or buying a second-hand appliance, a licensed gas fitter changes the right parts, adjusts it and tests it, a proper conversion, not a guess. Never try to run an appliance on the wrong gas.
If you are changing over a cooktop, oven, heater or gas hot water unit, request a callback or see our gas fitting service. Josh will connect it, test it, and leave you with the certificate.