Hi Clayton, we have one type of gauge that measures the suction when no air is moving (like when someone sucks the air out of plastic bottle). But note that even if you have a clog the pressure will build and give you a correct reading. This devise is only good to see if there are any air leaks or if the motor is really tired. Beware that the smallest of air leaks quickly lowers the reading. WaterLift measurement is what this reads and when you see the motor's maximum waterlift specification online, the motor will be 10 to 15 behind it in a normal sealed vacuum system. If you want to measure the airflow or CFM those are over $1000 per machine and we don't sell them. Check our our sealed vacuum gauge.
To make sure you understand, it doesn't measure airflow, just sealed suction. Humans can pull more sealed suction on this guage with their mouth then any vacuum could but we don't make good vacuums because we don't have the ability to inhale tons of air. These also will not tell you if you have a clog. Even with a clog, the sealed measurement will be the same though in may take a little more time to build up the suction. It will tell you if there is a hole in your system because the suction will be a lot less than is rated for the motor.