Look inside and you’ll see that holes allow air to flow into the inflatable when you use the pump. When you stop pumping the back pressure forces the simple non-return flap that’s located behind the holes, onto its seat to prevent air loss.
However, sometimes grit and dirt can stop this flap from creating an air tight seal and air will slowly escape. The symptoms are often mistaken for a puncture but the problem is quick and easy to rectify.
If the valve is losing air then it is time to strip down the valve. You will find the complete valve can be unscrewed from the inflatable, although it is held on by a simple light plastic strap to prevent it getting lost. Once open, it reveals the bottom of the non-return flap.
Gently fold this back and wipe over both flap and plastic seat with a damp cloth to remove any dirt or grit that might be stopping the air tight seal.
Reassemble and inflate to test it is now air tight. Job done!
NOTE — Prevention is better than cure so ALWAYS screw the protective cap back on when you’ve finished pumping up an inflatable. It will help stop contaminants entering the valve as well as reduce air loss if the valve fails. And make sure nothing enters when in use – for instance, check the pump hose has not got any mud or grit on the end you insert into the valve.