There is a hissing sound at the pressure regulator when I open the shut-off valve. Does that mean that gas is escaping?

Summer. Sunshine. Barbecue weather. You connect the pressure regulator/pressure reducer to the LPG cylinder and connect it to the gas barbecue using the hose assembly. You are already imagining the steaks sizzling away on the grill. The wonderful aromas of roasting meat and vegetables are already in the air and your mouth is starting to water. You open the gas cylinder valve and hear a hissing sound. Does this mean you need to cancel your barbecue because the pressure regulator might have a leak?

First of all: No! You don’t need to worry if there is a brief hissing sound when you open the gas cylinder valve. This is completely normal and even important for the LPG system to function at its best. Why? We’re about to tell you.

Air displacement

Pressure regulators from GOK have a something called a vent hole. When non-pressurised, meaning when the gas cylinder valve is closed, the diaphragm of the pressure regulator is in the neutral position. Now, when you open the gas cylinder valve, the diaphragm in the housing moves towards the vent hole and reduces the volume in the cap. Part of the air escapes to the outside through this vent hole.

Every pressure regulator which is connected to 5, 11 or 33-kilogram gas cylinders has a vent hole. This is where air escapes from when you open the gas cylinder valve, and you can hear it by the striking hissing sound.

Video evidence

The hissing sound that you hear when you open the shut-off valve of the propane gas cylinder is therefore not due to gas escaping from the pressure regulator. Here’s a video to give an example for a few pressure regulator models, this visualises how the air escapes:

Pay attention to the smell

By the way: If you do have a dangerous leak in your LPG system, you would notice an unpleasant smell. LPG has odour added to it which smells like rotten eggs.

As this isn’t the case here, there’s nothing to prevent you from hosting your barbecue. Once you have performed a simplified leak test for the whole LPG system, you can start putting your food on the barbecue without a care.

Hissing on all pressure regulators

In the end, it doesn’t matter whether it’s an LPG system, a gas-powered barbecue, gas stove, heater or heating mushroom. All pressure regulators which connect to a gas cylinder have a vent hole and you will hear the classic hissing sound shortly after you have opened the gas cylinder valve.