John Guest fittings

Push-fit fittings join beer and gas line without tools: the tube pushes into the collet, grips, and seals, and releases again by pressing the collar in and pulling the tube out.

  • Sizes refer to the tube's OUTSIDE diameter, not the bore
  • Cut the tube square u2014 an angled cut is the usual reason a joint weeps
  • Push fully home, then pull back to check the collet has gripped

Showing 1–24 of 93 results

Showing 1–24 of 93 results

Sizing is the thing that catches people out. Push-fit fittings are specified by the OUTSIDE diameter of the tube they accept, not the bore. A fitting described as 3/8 takes 3/8 inch outside diameter tube and nothing else. Reducers, elbows and tees exist precisely because a cellar usually runs more than one size u2014 commonly a larger bore on the beer line and a smaller one on gas u2014 and every junction between them needs the right adapter rather than a forced push.

How to choose

What to know

The tube has to be cut square. A tube cutter costs very little and a diagonal cut is the single most common cause of a joint that weeps under pressure, because the O-ring inside the collet cannot seal against an angled face. Push the tube fully home until it stops, then tug it back to confirm the grip has taken.

What to know

Fittings of this kind are designed to be taken apart and remade, which is what makes them the standard in a cellar where lines get moved. Collets and O-rings do age; if a joint that has been remade several times starts weeping, replace the fitting rather than persevering with it.

Common questions

Is a 3/8 fitting the same as 3/8 bore tube?

No, and this is the most common ordering mistake. Push-fit sizes describe the outside diameter of the tube. Check what your existing line actually measures across the outside before ordering.

Why is my push-fit joint leaking?

Usually the tube was cut at an angle, or it was not pushed fully home. Take it apart, cut the end square with a proper tube cutter, and push it in until it stops.

Can push-fit fittings be reused?

Yes, that is the point of them. They are designed to be disconnected and remade. If a fitting has been remade many times and starts to weep, replace it u2014 the collet and O-ring are the parts that age.

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