The bullnose, or POL, connector has a left-hand thread that screws into the cylinder valve. This means you turn it anti-clockwise to do it up, and clockwise to remove it.
Most propane regulators in the UK have this kind of fitting, which is also known as a male connector or male inlet. The connector is found on both high and low pressure regulators.
Nut or handwheel
POL regulators are fitted with either a nut, which you do up with a gas spanner, or a handwheel which you can tighten with your fingers.
Although the connection needs to be secure, be careful not to over-tighten the nut as this can damage the thread.
Regulator vent
Vents vary in appearance. Some are recessed – sunk into the body of the regulator – while others sit on top.
Whichever design you have, it’s important to make sure that the vent is facing downwards when you connect the regulator. This is to stop rainwater, debris or even cooking oil getting into the mechanism.
The purpose of the vent is to let the regulator ‘breathe’, as it needs air flow to let the diaphragm move up and down inside. It also allows excess gas to escape if the pressure becomes too high.
If the vent gets clogged up it will stop the regulator from working properly and could lead to a dangerous build-up of gas. For this reason many vents are protected by a mesh screen.
Regulator outlet pressure
Low pressure regulators for use with portable appliances deliver a fixed outlet pressure which is printed on the outer casing. This means that no matter how fast the gas has left the cylinder, it will always be released from the regulator at a pre-set pressure – in this case, 37mbar.
The pressure is measured in millibars, or mbar for short. (A millibar is one thousandth of a bar.) Generally, anything under 500mbar (0.5bar) is regarded as low pressure.
Regulator capacity
The regulator’s capacity, also known as gas flow rate, is also printed on the casing. This tells you how many kilograms of gas can be processed by the regulator in one hour.
For example, if you are using a 15kg propane cylinder to power your barbecue and the capacity is given as 1.5kg per hour, the gas will last 10 hours at full flow, or 20 hours at half the flow rate.
Regulator outlet nozzle
The outlet nozzle, also called a hose tail, hose barb and spigot, is a pipe that connects to the hose and carries the gas from the regulator to the appliance. It features ridges which help hold the hose clips in place.
The size of the nozzle is measured by its diameter in millimetres, and will usually fit the UK standard low pressure gas hose size of 8mm internal diameter.