Replacement of gas hose in the vehicle: How to find the right replacement gas hose for your gas system
When replacing a gas hose in the vehicle, many users notice that the old hose suddenly has a right-hand thread connection. This not only looks unfamiliar, but also seems incompatible with the previous connection configuration. What has happened – and which replacement gas hose is the right one?
In many leisure vehicles, gas hose assemblies are installed between the pressure regulator and the fixed piping, featuring a connection configuration of union nut G ¼ LH-UN x pipe nozzle 8. Once the replacement interval is reached, the search for a suitable replacement gas hose begins. However, upon removal, an irritating sight often presents itself: the removed gas hose has one union nut with a right-hand thread and one with a left-hand thread. The reason for this lies in the function of the cutting ring fitting. While technically entirely correct, this often leads to misunderstandings in everyday use. In this article, we explain why this confusion arises, what it means for the replacement of the gas hose in the vehicle, and what to consider when selecting a replacement hose.
Original Gas Hose Connection in the Vehicle
Many gas systems in leisure vehicles are equipped with hose assemblies featuring the following connection configurations:
- Union nut G 1/4 LH-UN x pipe nozzle 8
This variant uses the so-called cutting ring connection. During initial installation at the factory or in original equipment, a cutting ring is pushed onto the pipe nozzle together with the union nut and tightened. The cutting ring cuts into the pipe nozzle with the union nut, creating a permanent, gas-tight connection.
However, this type of assembly causes a lasting visual alteration to the pipe nozzle. When the connection is later loosened, the cutting ring and union nut remain on the pipe nozzle. As a result, when removing the old gas hose, it appears as though it had a different connection. When searching for a new hose assembly in specialist shops, it then becomes apparent that such a hose is not available pre-assembled.
The left part of the image shows a gas hose with pipe spigot and G 1/4 LH-UM union nut. During initial installation, the cutting ring and union nut are pushed onto the pipe spigot and secured to the bulkhead fitting. On the right, all components are shown at a glance.
In the left section of the image, the cutting ring and union nut can be seen in the tightened position on the pipe spigot. These ensure a permanently leak-tight connection. When loosened, the cutting ring and union nut remain on the pipe spigot and permanently alter its appearance.
Why the Gas Hose Appears Different After Removal
When the union nut with the cutting ring is pushed onto the hose with pipe nozzle and tightened, the cutting ring cuts permanently into the pipe nozzle. The component compresses axially and radially onto the nozzle, thereby sealing the connection.
This means: what was originally installed as a pipe nozzle appears, after the hose is removed, to be a threaded connection. The union nut along with the cutting ring remains on the pipe nozzle, creating the impression that the gas hose had a right-hand thread connection.
In other words, the connection configuration has not fundamentally changed – it has merely undergone a visual alteration due to the nature of the connection during disassembly.
Further technical details on the function can be found in the datasheet on cutting ring fittings.
How to Choose the Right Replacement Gas Hose During Replacement
If you wish to replace the gas hose assembly with the connection configuration G 1/4 LH-UN x pipe nozzle 8 (typically item no. 04 436 02 in caravans), please note that the connection is not fully included in the set. You must be sure to order the appropriate connection components separately.
The following components are required:
- Union nut: item no. 07 108 00
- Cutting ring: item no. 07 151 00
Both parts are necessary to create a new, gas-tight connection.
If you are unsure, we recommend contacting the manufacturer. You can reach us by email at info@gok.de or by phone at 09332 404-0.
Further technical details can be found in the installation instructions for cutting ring fittings.
FAQ – Frequently Asked Questions About Replacing the Gas Hose in the Vehicle
Why does my removed gas hose suddenly look like it has a right-hand thread connection?
This is because, during initial installation, a cutting ring and a union nut were firmly mounted onto the pipe nozzle. When the connection is loosened, the cutting ring and nut remain on the pipe nozzle – visually making it appear as though the hose had a threaded connection.
Can I reuse existing cutting rings?
No, these cut into the pipe nozzle during the initial installation and remain there.
Which parts do I need to order separately when using a gas hose with pipe nozzle connection?
You will need a union nut (item no. 07 108 00) and a new cutting ring (item no. 07 151 00).
When should the gas hose in a motorhome or caravan be replaced?
A gas hose in the vehicle should be regularly checked and replaced at the prescribed intervals – usually every ten years (as is the case in Germany and Austria), or according to the manufacturer’s specifications.
How long does a gas hose in a motorhome or caravan last?
The actual durability is not the decisive factor. In many countries, there is a mandatory replacement interval that specifies how long gas hoses may be used in a vehicle.
