How Much Gas is Left in the Gas Bottle?

Checking the level of remaining gas, in a gas bottle, is an easy process

To make sense, it helps to first explain how LPG works.  LPG is stored under pressure, as a liquid, in a gas bottle.  It turns back into a gas by 'boiling' into gas vapour.   This happens at a very low below zero temperature.  To boil, the liquid LPG draws heat from the steel walls of the gas bottle.  This, in turn, makes the gas bottle feel colder than the ambient temperature.   The gas bottle gets even colder when you are actually using the gas.  Under the right conditions, when you are using gas very rapidly, ice can even form on the gas bottle!

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So, we use this to tell how much gas is left in a gas bottle.  How?  Well, we pour hot water down the side of the gas bottle to heat the steel.  The steel above the level of the gas will retain the heat longer than the steel below the level of the gas.  This makes it feel warmer above and cooler below the gas level.  The point at which you feel the temperature change is the level of the gas inside the bottle.

The following test works with either 45kg home gas bottles or BBQ gas bottles

How to check how much gas is left in your gas bottle:

How full is the gas bottle? Hot water test 1.    Do NOT use boiling water, as you would risk scalding yourself. Water from the hot water tap of your home should work fine.

2.    Using care, SLOWLY pour the hot water down one side of the gas bottle. More is better, as it will make it easier to feel the difference in temperature.

3.  A line of condensation may appear, indicating the gas level.  If not:

3.    Wait a few seconds and then run your hand down the same side of the gas bottle, where you poured the water.

4.    You should feel a change of temperature at the level of the gas. If you feel no difference, the gas bottle may well be empty.

Quick Tip:

The test works even better during or after you use one of your LPG appliances.  For example, if you have LPG hot water, perform the test right after someone takes a shower.

Also, please remember that gas bottles are designed to be full at 80% or just over 3/4. This allows for the natural expansion of the gas during warmer temperatures.

For safety reasons, NEVER open the valve on an unattached gas bottle to check for remaining gas, even if you think it is empty.

An alternative way to check a BBQ size gas bottle is by using a scale.  The tare (empty) weight of the bottle is stamped on the neck ring. The difference between the scale reading and the tare weight should indicate approximately how much gas remains in the bottle.

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Please see important information for New Users of Home LPG

Comments, questions or feedback? Please Email us at: [email protected]

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