Everything You Need To Know About Your Caravans’ Gas Systems

Your caravan’s gas system powers some of the most essential functions for comfortable living on the road: hot water, cooking, heating, and refrigeration. Understanding how this system works isn’t just about convenience; it’s about safety, efficiency, and getting the most from your setup.

Most Big Lappers rely heavily on gas for daily living. Unlike mains power that you can only access at powered sites, gas gives you independence to free camp for extended periods while still enjoying hot showers and cooked meals. The system itself is relatively simple, but there are important safety considerations and regulations you need to understand.

What Is LPG and Why Caravans Use It

LPG (Liquefied Petroleum Gas) is a mixture of propane and butane gases that’s compressed into liquid form for storage and transport. In Australia, automotive LPG typically contains about 60% propane and 40% butane, though this can vary by supplier and season.

Caravans use LPG because it’s energy-dense, widely available, relatively inexpensive, and burns cleanly. A 9kg cylinder contains roughly the same energy as 130 litres of petrol, making it an extremely efficient fuel source for heating and cooking applications.

The gas exists as liquid under pressure inside your cylinders, but vaporises as soon as it leaves the cylinder valve. This vapour is what feeds your appliances through the gas lines. Temperature affects this vaporisation process, which is why some caravanners experience reduced gas flow in very cold conditions, particularly with butane-heavy mixes.

Core Components of Your Gas System

Your caravan’s gas system consists of several key components working together to deliver gas safely from storage to appliances.

Gas Cylinders and Mounting

The cylinders store your LPG supply and mount securely to your van’s A-frame, rear bumper bar, or dedicated compartment. Most caravans carry two cylinders so you can switch to the spare when the first runs empty. The mounting system must comply with Australian standards and allow proper ventilation.

Regulator and Changeover Valve

The regulator reduces the cylinder pressure (around 800-900 kPa) down to a usable appliance pressure (typically 2.75 kPa). If you have two cylinders, a changeover valve automatically switches to the spare cylinder when the primary empties, though some setups require manual switching.

Gas Lines and Fittings

Copper or approved flexible hoses carry gas from the regulator to each appliance. These lines include shut-off valves, test points for leak detection, and specific fittings for different appliance connections. All connections must use approved sealants and fittings rated for LPG use.

Appliance Connections

Each gas appliance connects to the main gas line through its own isolation valve and typically includes safety features like flame failure devices or thermal cut-offs.

Gas Cylinder Types and Sizes

Australian caravans typically use POL (Prest-O-Lite) connection cylinders, which are the standard for LPG appliances. You’ll encounter several common sizes depending on your van’s storage capacity and usage needs.

Standard Cylinder Sizes

The 9kg cylinder is the most common choice for caravans, offering a good balance of capacity and weight. These cylinders measure approximately 610mm tall and 310mm diameter, weighing about 18kg when full.

Some larger vans accommodate 18kg cylinders, which obviously provide longer runtime but add significant weight (around 35kg when full). Smaller vans might use 4kg or 6kg cylinders, though these require more frequent refilling.

Swap vs Refill Options

You can either swap empty cylinders for pre-filled ones at service stations and hardware stores, or refill your own cylinders at dedicated LPG outlets. Swapping is more convenient and ensures you get properly tested cylinders, but refilling is typically cheaper per kilogram of gas.

Swap bottles often contain slightly less gas than their rated capacity (a 9kg swap might contain 8.5kg), whereas refilling your own cylinder gets you the full capacity you pay for.

Gas Appliances in Your Van

Most caravans run multiple appliances off the gas system, each with different consumption rates and operational requirements.

Hot Water Systems

Gas hot water heaters are extremely popular because they heat water quickly and don’t drain your batteries. A typical instant gas hot water system uses about 1-2 MJ per hour of operation, while storage systems use gas periodically to maintain temperature.

Cooktops and Ovens

Gas cooking provides instant heat control and works regardless of your electrical situation. A typical gas burner consumes roughly 6-9 MJ per hour on high heat, meaning you can run a burner for about 15-20 hours from a 9kg cylinder.

Heating Systems

Gas heaters deliver excellent warmth output but consume gas relatively quickly. A typical caravan gas heater uses 4-8 MJ per hour depending on the setting, so expect a 9kg cylinder to provide roughly 20-35 hours of heating.

Absorption Refrigerators

Three-way fridges can run on gas when you’re camping without power. Gas operation typically consumes about 400-600g of LPG per 24 hours, making it quite efficient for continuous refrigeration.

Safety Features and Regulations

Australian gas systems incorporate multiple safety features to prevent leaks, explosions, and carbon monoxide poisoning.

Pressure Relief and Leak Detection

Your regulator includes pressure relief valves that vent excess pressure safely. Many systems also include leak detection devices that shut off gas flow if a significant leak is detected in the lines.

Flame Failure Devices

Modern gas appliances include flame failure devices that automatically shut off gas supply if the flame goes out unexpectedly. This prevents dangerous gas accumulation from unlit burners or pilot lights.

Ventilation Requirements

Gas appliances require adequate ventilation for safe combustion and to prevent carbon monoxide buildup. Your van’s design must include specific ventilation openings sized appropriately for the gas appliances installed.

Gas Detector Systems

While not mandatory, many caravanners install LPG gas detectors that alarm if gas concentration reaches dangerous levels inside the van. These devices can provide early warning of leaks or incomplete combustion.

Installation and Compliance Standards

Gas installations in recreational vehicles must comply with Australian Standard AS/NZS 5601.2, which covers LPG installations in caravans, motorhomes, and similar vehicles.

Licensed Installation Requirements

All gas work must be performed by licensed gas fitters who can issue compliance certificates. This includes initial installation, modifications, and major repairs. You cannot legally install gas appliances yourself, even if you’re experienced with other trades.

Inspection and Testing

New installations require pressure testing and leak detection before commissioning. The gas fitter must provide a compliance certificate confirming the installation meets Australian standards.

While not legally required for existing systems, having your gas system professionally inspected every few years is good practice, especially if you’ve experienced any issues or made modifications.

Documentation and Records

Keep your gas compliance certificates with your van’s documentation. Some caravan parks and insurance companies may request proof of compliant gas installation, particularly for older vans or if you’ve made modifications.

Essential Maintenance and Checks

Regular maintenance keeps your gas system safe and efficient. While major work requires professionals, you can perform several important checks yourself.

Visual Inspections

Check gas lines for damage, corrosion, or loose fittings during your regular pre-trip inspections. Look for signs of gas leaks like dead vegetation around cylinder storage areas or unusual hissing sounds.

Inspect cylinder mounting points for security and proper ventilation. Cylinders should be firmly secured but accessible for valve operation and removal.

Leak Testing

Test for leaks using soapy water solution at all connection points. Turn on the gas and brush soapy water over fittings, valves, and connections. Bubbling indicates a leak that needs immediate attention.

Never use open flames or electrical devices to check for gas leaks. The soapy water method is safe and effective for detecting even small leaks.

Appliance Maintenance

Clean burners and vents regularly to ensure proper combustion. Blocked jets or vents can cause incomplete burning, reducing efficiency and potentially creating carbon monoxide.

Have absorption fridges serviced annually if you use gas operation frequently. The burner and flue system require periodic cleaning to maintain safe, efficient operation.