Everything You Need To Know About Your Caravans’ Gas Systems

Your caravan’s gas system is one of the most critical components for comfortable life on the road, powering everything from your hot water and heating to cooking and fridges. Yet many Big Lappers find themselves confused by the terminology, regulations, and safety requirements that come with running gas appliances in a mobile home.

Understanding how your gas system works isn’t just about convenience—it’s about safety, compliance, and getting the most from your setup. Whether you’re dealing with LPG bottles, gas regulators, or wondering about automatic changeover systems, this guide breaks down everything you need to know about caravan gas systems in plain English.

Gas System Basics

Your caravan’s gas system operates on LPG (Liquefied Petroleum Gas), typically a mix of propane and butane that’s stored under pressure in steel cylinders. When you open a gas tap, the liquid converts to gas and flows through a regulated system to your appliances.

The basic components include gas bottles, a regulator to control pressure, safety valves, gas lines running throughout the caravan, and the appliances themselves. Everything must be connected in a specific sequence and meet Australian standards for safety.

Most caravans run on either 9kg or 4.5kg gas bottles, though some larger rigs use 18kg bottles. The choice depends on your space, weight capacity, and how much gas you typically use. Two bottles are standard—one in use, one as backup—with either manual or automatic changeover systems.

LPG Bottles and Sizes

Standard 9kg bottles are the most common choice for caravans, offering the best balance of capacity and weight. They’ll power a typical setup (fridge, hot water, cooktop, heating) for 2-3 weeks of normal use. The bottles are 315mm diameter and 580mm tall, fitting most caravan gas compartments.

Smaller 4.5kg bottles work for lighter rigs or weekend trips but need more frequent swapping. They’re 267mm diameter and 410mm tall. Some travellers use these when weight is critical or space is limited.

Larger 18kg bottles are found on big rigs and motorhomes where space and payload allow. They’re 315mm diameter but 870mm tall, requiring specific mounting arrangements. The extra capacity means less frequent bottle changes but more weight to carry.

You can swap bottles at most service stations, caravan parks, and hardware stores across Australia. Swap prices typically run $25-35 for 9kg bottles, though remote areas may charge more. Always check the test date—bottles must be retested every 10 years.

POL vs ACME Valves

Older bottles use POL (Prest-O-Lite) valves that screw on clockwise and require a spanner to tighten. Newer bottles use ACME valves with a quarter-turn connection and built-in safety features. Most modern caravans have ACME regulators, but you can get adaptors if needed.

Regulators and Valves

The gas regulator is your system’s pressure control centre, reducing bottle pressure from around 800-1000 kPa down to the 2.75 kPa that appliances need. Without proper regulation, appliances would burn too hot, waste gas, or potentially become dangerous.

Single-stage regulators are the basic option, providing adequate pressure control for most setups. Two-stage regulators offer more precise control and better performance when bottles get low. They’re worth the extra cost if you run multiple gas appliances simultaneously.

Manual vs Automatic Changeover

Manual changeover systems require you to physically switch the gas line from an empty bottle to a full one. They’re simple, reliable, and cheaper to install. You’ll know when a bottle’s empty because appliances stop working.

Automatic changeover systems detect when the primary bottle empties and switch to the reserve bottle without interruption. They typically include a gauge showing which bottle is in use and when the changeover has occurred. This prevents situations where your fridge stops working overnight or your hot water goes cold mid-shower.

Gas Lines and Connections

Gas lines in caravans use either copper tubing or flexible rubber hoses, depending on the application. Fixed lines running through walls and floors typically use 8mm copper tubing, while connections to appliances often use flexible hoses for ease of installation and servicing.

All connections must use approved fittings and be tested for leaks. The system operates at low pressure (2.75 kPa), but gas leaks can still create serious safety hazards. Every joint, valve, and connection point is a potential failure spot that needs proper installation and regular checking.

Quick-connect fittings are becoming more common for appliance connections, allowing easy disconnection for servicing. However, these must be gas-rated quick-connects, not generic hardware store fittings. Using incorrect components can cause leaks or appliance malfunctions.

Gas Outlets and Bayonet Fittings

Many caravans include external gas outlets for connecting portable appliances like BBQs or camp ovens. These typically use bayonet fittings with quarter-turn connections. The outlet should include an isolating valve so you can shut off gas to external appliances when not in use.

Gas Appliances in Your Caravan

Three-way fridges are the biggest gas users in most caravans, consuming roughly 250-400 grams per day depending on size and ambient temperature. They’ll eat through a 9kg bottle in 25-35 days of continuous operation, making them your primary gas consumption concern.

Hot water services typically burn 150-250 grams per hour when heating, but only run intermittently. A 22-litre system might use 300-500 grams per day with normal use. Instant hot water systems use more gas per minute but only when you’re actually drawing hot water.

Cooktops and ovens vary enormously in consumption based on use patterns. A large oven might burn 400 grams per hour, while cooktop burners use 100-200 grams per hour each. Most cooking doesn’t run appliances continuously, so daily consumption is typically modest compared to fridges and hot water.

Heating Systems

Caravan heating can use significant gas in cold weather. Ducted heating systems might consume 200-400 grams per hour, while compact space heaters use 100-250 grams per hour. In winter camping, heating can become your largest gas expense.

Some heating systems include electric elements for when you’re on powered sites, reducing gas consumption. Others offer thermostatic control to cycle on and off, maintaining temperature without constant burning.

Safety and Compliance

Gas work on caravans must comply with AS/NZS 5601.2, the Australian standard for gas installations in recreational vehicles. This covers everything from pipe sizing and routing to ventilation requirements and safety devices. Only licensed gas fitters can legally work on fixed gas installations.

Every caravan gas system needs adequate ventilation to prevent gas buildup in case of leaks. High-level vents allow gas to escape (LPG is heavier than air when mixed with normal air), while low-level vents provide combustion air for appliances. Blocking or modifying these vents creates serious safety risks.

Gas Detection and Shut-off

Modern caravans often include gas detection systems that monitor for leaks and automatically shut off gas supply when problems are detected. These systems typically include sensors near the floor (where LPG accumulates) and automatic shut-off valves at the bottles.

Manual emergency shut-offs should be accessible from inside the caravan, allowing you to quickly stop gas flow in an emergency. Know where your shut-offs are located and how to operate them before you need them.

Maintenance and Troubleshooting

Regular leak testing is essential for gas system safety. Use soapy water on all connections, looking for bubbles that indicate escaping gas. Check connections after any work on the system, when changing bottles, and periodically during normal use.

Gas appliances need regular servicing to operate safely and efficiently. Three-way fridges should be professionally serviced every 2-3 years, including cleaning the flue and checking the gas burner. Hot water services need similar attention, particularly the flue and combustion chamber.

Common problems include blocked burners (often from insects or debris), faulty thermocouples that shut off gas flow, and regulator issues causing poor appliance performance. Many issues require professional attention, but some basic maintenance can prevent problems.

Troubleshooting Gas Flow Issues

If appliances won’t light or burn poorly, start by checking gas bottle levels and connections. Ensure the bottle valve is fully open and the regulator is properly connected. Check for kinked or damaged hoses that might restrict flow.

Regulators can fail or become contaminated, causing pressure problems that affect appliance operation. If multiple appliances perform poorly simultaneously, the regulator is often the culprit. This requires professional diagnosis and replacement.