Chapter 4

The Dreaded @

We encourage everyone to shop around and compare vacuum systems, but there’s one thing you need to watch out for when it comes to deciphering wishy-washy performance claims.

Almost every vacuum company states their performance figures at either end of the spectrum, since those figures will always be the largest for each typical scale. For example, when making claims about volume performance, many companies use what’s known as the “open condition volume.” This is the volume achieved by a vacuum producer when pulling zero vacuum. They also use conditions you would only find at zero flow to make vacuum performance claims.

Combining those two figures is simply meaningless. It’s like measuring your car’s mileage while it’s running in your driveway. To make matters worse, some companies confuse the situation by combining the two performance claims using the @ symbol. For more clarity in cases like these, do your homework and don’t be afraid to ask questions.