This is an easy way to tell if your radon system is pulling the right amount of air for the type of system you have, also it will help you know if your system is in need of service by one of our technicians. The readout on the manometer should be between 0.5in – 1.75in. In most cases these are acceptable levels indicating, your system is operating correct. When your Radon system is shut off the fluid should rest at zero if it does not then your manometer is low on fluid. It is important to understand that these readouts will indicate if your system is in need of any maintenance and should be serviced.