Gas Bottle Level Indicator – How to Check Gas Bottle Level

How to Check Gas Bottle Level Indicator. The following are 5 steps to checking you gas bottle level indicator…

 1. Fill up a bucket (more is better) with hot tap water.

2. Slowly pour it down the side of the gas bottle.

3, Run your hand down, feeling for a temperature change

4, The gas bottle level indicator is the point where the steel goes from warm to cold.

5. If it is some distance from the bottom, you’re OK. If you feel no temperature change, it may be empty.

Bucket of hot tap water

CAUTION: Be careful not to scald yourself with the hot water. Do NOT use boiling kettle water. 

Quick Tip for How to Check Gas Bottle Level

Checking your gas bottle level indicator is even easier if you check whilst using or directly after using a gas appliance. Check when your heater is running or immediately after someone showers. You may not even need the hot water to feel the temperature difference. 

45kg Gas Bottle – Full at 80%

 A 45kg gas bottle is full when it is at 80% of the internal volume. The remaining 20% is called ullage and is designed into the gas bottle to allow for expansion in warmer weather.

This means that when you do your hot water test on a full bottle, it will only look a little more than ¾ full. Don’t worry, you are still getting your full 45kg at the 80% fill level. In essence, the 45kg gas bottle is designed to be oversized, for expansion.

45kg Gas Bottle

45kg Gas Bottle Dimensions

A 45kg gas bottle dimensions include a height of approximately 1250mm and a diameter of about 375mm. The volume of a 45kg gas bottle is 88 litres, which contains about 2200 MJ of energy.

The empty weight of a steel 45kg gas bottle is approximately 33kg, meaning that the full weight would be 78kg (33 + 45 = 78kg).

9kg Gas Bottle Dimensions – BBQ Gas Bottles

In comparison, 9kg gas bottle dimensions are only 460mm in height and 310mm in diameter. The volume of a 9kg gas bottle is 16.66L. 

Keep in mind that BBQ gas bottles from swap schemes are only filled to 8.5kg or 15.73 litres. So, about 5.6% less with a swap scheme refill.

ALWAYS ASK THE 45kg GAS BOTTLE PRICE BEFORE ORDERING a gas bottle refill or exchange. 

LPG Vaporisation – LPG Boiling

Liquid propane turns to gas by boiling and turning from a liquid to gas vapour, a process called vaporisation. To boil, the liquid LPG draws heat from the steel walls of the gas bottle which, in turn, get heat from the ambient air. Vaporisation also makes the gas bottle feel colder than the ambient temperature.

The area of contact between the liquid LPG and the steel walls is referred to as the “wetted area”. As the level drops, so does the rate of vaporisation, as the wetted area becomes smaller. 

The rate of vaporisation also declines when the ambient temperature drops. For example, a 45kg gas bottle that is 30% full will vaporise at the rate of 184 MJ/hr at 16˚C but only 115 MJ/hr at -1˚C. This can be an issue with multiple appliances running at the same time or even with some instant hot water units requiring high vaporisation rates.

LPG Vaporisation
in a 45kg Gas Bottle

LPG is stored as a liquid under pressure. It boils and turns back into gas vapour at -42°C or -45°F (at 1 ATM). This is called vaporisation. When you turn on a gas appliance, it relieves some of the pressure and then takes heat from the steel walls of the gas bottle to boil. It looks just like clear boiling water when it vaporises.

So, it becomes cooler below the level of the boiling liquid, as it extracts the heat from the steel. The level at which this happens is you gas bottle level indicator for the liquid LPG. The level above contains LPG in its gaseous form. 

Vaporisation explains the principle behind the hot water test and why you feel a change in temperature at the level of the liquid gas. 

ALWAYS ASK THE 45kg GAS BOTTLE PRICE BEFORE ORDERING a gas bottle refill or exchange


Questions, comments or feedback? Please email us at:

The information in this blog is retrieved from various resources and is believed to be correct when published. The information may not be error free nor applicable in all circumstances.