This is a Modern Day / MD Central Vacuum compatible vacuum product.
This Vacuum Cleaner Water Lift Suction Gauge measures Waterlift (vacuum) at a sealed opening. Place on the end of vacuum pipe and read the dial to determine suction power. Measures from 0 to 160 inches of Waterlift.
When you are trying to determine the water lift on any vacuum system it is important to understand what the terminology “Water Lift” really means.
Water lift is a measurement of the strength of any vacuum that is produced by the suction that the motor(s) the system uses to produce that suction. Water lift suction gauges used on vacuum systems and are calibrated in what is referred to as “Inches of Water Lift”. So to put this in a practical manner it is the equivalent to taking a vertical tube, placing the bottom in a container of water then attaching a vacuum hose to the top of the tube and measuring how high above the water surface the water in the tube rises.
For those who are technically oriented one cubic inch of water weighs 0.036 pounds. Therefore the negative pressure in pounds per square inch can be determined by multiplying the water lift that is displayed on your water lift gauge by 0.036. In addition, if you are using suction that uses a mill bars (mbar) rating system you may multiply that number by 0.4 to convert it to inches of water lift.
Measurements are 4 inches long and 2 1/2 inches wide.