Testing Principles for Pressure

You may be aware that using water to isolate leaking plumbing lines during a pressure test is preferable, but do you know why?

When put under pressure, water does not compress air does.

This is the fundamental reason why we advocate utilizing water instead of air for pressure testing. During a pressure test, if air and water are both present in the plumbing line, the air will compress under pressure and may cause the pressure decrease you notice on your gauge to be slower. In the long run of plumbing, this can lower the pressure drop to a negligible level, giving the appearance that a leaky pipe was under pressure.

When there is a leak, air escapes faster than water.

When air escapes from a leak, the pressure drops more faster than when water does. When trying to get air to a leak in order to use a listening device to pinpoint the leak, look for a sudden drop in pressure. Once this occurs, you'll be able to detect that air has reached the leak and start listening for the distinctive bubbling or gurgling sound.

Water remains low in the plumbing pipe, while air remains high.

In a plumbing line, water always sinks to the bottom and air always rises, so the two never remain "mixed." Water and air will separate in the pipe even if they are both stimulated simultaneously. If the leak is at a low section of the plumbing and none of the water has been purged from above the leak, you won't make a good leak noise. Additionally, if you apply pressure from the bottom end of the plumbing, you may hear distracting noises as air bubbles move through the water.

The Bottom Line

Finding leaks in swimming pool plumbing involves two steps: locating the leak by listening through the pool surface and isolating the leak with a pressure test. Make sure the line is fully filled with water before conducting pressure testing to ensure accuracy. When you're ready to start listening, check to see if air is getting to the leak so that it can produce a loud sound.

You can visit Wingoil to learn more information about Pressure Testing Equipment.