The pressure regulator of your high pressure jetting machine ensures a safe working environment. By using the hand wheel you can lower the water pressure to clean smaller or fragile drains or sewers. Also when using a spray gun, it is advisable (especially for machines with a bigger maximum workload) to reduce the pressure before you start to work with it. The automatic pressure regulator has a bypass-function which ensures that the overload of water gets back into the tank, when there is overpressure at the jetting nozzle. This usually happens when the nozzle inserts are blocked. This can cause potentially dangerous situations. Without a proper functioning pressure regulator, the water will automatically find another way-out, which could cause leakage, pump damage, or worst case an eruption in the high-pressure circuit or hose.