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How To Select The Correct Regulator & Gas Hose

Article by Peter Smith - Caravans Plus
Read Time: 5 mins

Which Pigtail or Regulator do I need for my Caravan, Camper Trailer or Motorhome?

Why are there so many different regulators available?
What is high pressure and low pressure gas?
Which hose or pigtail should I use?
What is a two stage regulator?
Do I need a test point?

Your RV gas cylinder holds gas under high pressure and that must first be reduced by a regulator before being circulated to your low pressure appliances in your RV.

You may also hear of high pressure gas stoves or lights, these are different from appliances fitted to your RV as they do not require a regulator and are connected directly to gas cylinders. High pressure appliances have very fine gas jets and are susceptible to blocking.

1) Pigtails

Pigtails are the hoses or copper pipes that get the gas from the cylinder to the regulator. Because they are before the regulator, they are carrying gas at high pressure and must be rated to do this. All pigtails shown on Caravans Plus are rated for this high pressure gas.


(a) Copper pipe - these could last as long as your RV, however continued bending will cause the copper to fatigue, and rough handling can cause these to kink.

(b) Rubber hose with protective stainless steel braiding. These have been the most common in the recent past, however they do suffer from the rubber breaking down over time. The rubber particles have also resulted in premature failure of regulators. These are slightly more economical.

(c) S-Core which has a flexible corrugated stainless steel inner tube covered with stainless steel braiding and a protective yellow plastic outer skin. These are considered the most advanced available. They are flexible but will not kink under normal use. There is no rubber to get into the gas lines.
A cross section is shown below in photo

Pigtail details

(e) Shows the two possible threads that connect to the regulator. This is where most confusion lies, because when you only have your hose, it is difficult to identify. Colour e.g. brass or zinc plated makes NO difference. The best way is to measure across the outside of the thread, as the 1/4" NPT thread measures approx 12.5mm. The thread is tapered so the measurement may vary slightly.

The NPT thread goes directly into the regulator, so it is only used when one cylinder is attached. The Inverted Flare usually goes into a two way valve where two cylinders are used. The exception is where an adapter (our part number: ID-7599) transforms the Inverted Flare to the NPT thread. Thread tape or liquid seal should be used for NPT.

(f) Shows the different POL fittings that may be fitted, and connect to the gas cylinder. The spanner style is more secure from theft, while the hand-wheel style is more convenient. The rubber O ring provides the seal and they should not be over tightened.

2) Regulators

Regulators can be single stage or two stage. Old caravans may still have a single stage regulator, but where a two stage regulator is being replaced or for new installations it is mandatory to install a two stage regulator. In a two stage regulator the final pressure is more even and will result in better performance of your appliances.

(a) Shows a two stage regulator that can be used with a single gas cylinder OR with the addition of a valve you manually select from two cylinders.
(b) Shows an automatic two stage regulator that directly accepts pigtails with 1/4" Inverted Flare thread.

Two Stage Regulators

Regulators must be mounted to a rigid mounting with the diaphragm vertical and the vent pointing downwards. Connections with these are shown later.

3) Test Points

Test Points are now mandatory in some states, so Caravans Plus recommends they be included in upgrades. They allow easy testing that the regulator is functioning correctly by loosening the test screw. Excess flow indicates a faulty regulator, while limited flow indicates blocked regulator or pigtail.

Shown below as ID-12106 and ID-12107 they are identical where they connect to the regulator outlet but come in different sizes to suit different copper pipe diameter. The correct flared nut ID-600 or ID-601 should also be selected.

Special flared nut ID-606 can be used to allow 5/16" pipe to be used with a Regulator kit that already includes the 3/8" test point.

Gas Test Point

4) Custom Regulator Kit

If the regulator kits we have available do not suit, you can use the following images to select the individual parts to make a custom kit. This allows for different pigtail hose lengths, different grade of hose or pipe, different connection to gas cylinder and connection to different copper pipe size.

Image below: Single Cylinder Regulator Kit

Regulator kit to single gas bottles

Image below: Twin Cylinder Regulator Kit

Twin Cylinder Regulator Kit

Using the above two diagrams, and pigtail descriptions earlier, you can make up the perfect regulator kit from the parts listed. Use the following links to get directly to parts needed.

1) Select the pigtail length and style.
2) Select the Regulator, Test Point and Change Over Value.

You can also place the ID number, e.g. ID-12107, into our Search Box at the top of each page.

Was this helpful?


  • comment-avatar


    Clear,precise explanation and most helpfull. Thanks

  • comment-avatar

    Very helpful pages. Explained precisely what I am looking for.

  • comment-avatar

    Johannes A

    Every time I open my gas cylinder cupboard door I am met with a strong odour of gas. My van was built in 2006, and as far as I know, there has never been any maintenance done to the hardware that connects my van to the two gas cylinders. This article has been most informative, and is a strong wake up call to me to get it seen to asap. Thanks. Hans

  • comment-avatar


    very helpful because explained in 'laymen' terms so the terms could be clearly understood.

  • comment-avatar


    More of a question than a comment as to why the s core pig tail is not suitable to be used on a single cylinder.thank you

  • comment-avatar


    What does it mean when gas is leaking out of the test point

  • comment-avatar


    Hi, I'm building my own little caravan (3m x 2m) and am wondering if I can just use a simple, over the shelf, gas hose to connect the regulator to an EXTERNAL cooktop like a companion cooktop? Or do I have to go the hole process of copper plumbing installed? so - Gas bottle to Gas pigtail hose, pigtail to two stage regulator, two stage regulator to flexible stainless steel mesh hose to cooktop :-). Is this OK?

  • comment-avatar


    Very good , pictures giving precise clarity to each item .

  • comment-avatar


    very clear and precise . makes it all clear thank you fred s

  • comment-avatar


    I have a 2003 motorhome and unsure when the regulator was last replaced. Is there a time limit on existing regulators to be replaced? Also, I am in South Australia, is there somewhere i can have my gas system checked and an updated compliance plate fitted please?

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