the gun,with the unloader valve, forms a valve system which gives the operator immediate contol of water flow. depressing the trigger allows water to flow out of the system through the nozzle under pressure . while releasing the trigger , it diverts water flow back to the pump. the pump ,however ,can be run for sometime. unloader operation is simple. when the trigger is depressed , a value in the gun opens and watermoves from the outlet side of the pump through the hose to the gun . when the trigger is released the valve closes and the unloader is activated by an increse in pressure .
the unloader diverts the flow of water from the outlet side of the pump back to the inlet side , causing water to flow in a loop back tothe pump under virtually no pressure rather than to the nozzle under operating pressure. flow may be directed back to the pump inletor to a float tank or other type of reservoir .