Are Push-Fit Fittings suitable for use on the suction side of a pump?

Are Push-Fit Fittings suitable for use on the suction side of a pump?

No! We do not recommend using the BPF series Brass Push-Fit fittings on the suction line of a pump!

The fittings are designed to seal against internal water pressure which presses outwards on the O-ring increasing the sealing efficiency. When installed in a suction application the vacuum pulls the O-rings inward which is more prone to leak. This combined with the fact that air will leak through 3 times easier than water, means there is risk of drawing air into the line and possibly burning out your pump. It is not worth the risk!

We recommended to use traditional pipe fittings with a quality thread sealing compound to plumb the suction side of your pump installation.

https://support.boshart.com/gray-magic-applications

It is for this reason that air is often used for leak testing.

To find leaks, a low pressure (30-50 PSI) air test is just as effective as high pressure (150 PSI) water test. This is because the viscosity and surface tension of water is greater than that of air. For example, the viscosity of water is about 89 times greater than the viscosity of air.