A 1″ AODD pump was selected for a paint transfer line simply because the piping was 1″. On water trials, everything looked fine. On actual paint, the problem appeared within hours.

Flow rate dropped, priming became slow, and operators started increasing air pressure to “push” the pump. The pump worked initially, but became unstable under real operating conditions.

The Common Selection Mistake

In many paint plants, pump size is decided by line size, budget, or availability. What often gets ignored are viscosity, suction conditions, and discharge back pressure.

A 1″ pump may run on water, but even moderate back pressure or difficult suction can make it unreliable on paint.

A Simple Check That Prevents Failure

Before finalizing a pump, perform a bucket-and-stopwatch test using the real paint at operating temperature, with the discharge routed back to the tank.

If free-flow itself is borderline, the pump will struggle badly once filters or restrictions are added. This single check prevents many wrong pump selections.