The Unloader Valve is designed to regulate and control the maximum pressure for the water systems on jetting and hydro excavation equipment. Provides safety and protection for the equipment and more importantly the operator. In the HX water systems, the unloader valve is plumbed after the water heater and before the operator hose reel station. This is a protection for the water heater from shock loads when the operator shuts off the digging wand. NOT TO BE CONFUSED WITH RELIEF VALVE! NOT FOR USE ON MONGOOSE PRODUCTS!