The working temperature must range between 40°F and 120 °F. The rotary brush can only be used with the trigger gun. The water that you use must not be dirty, sandy or contain any corrosive chemical products. With the detergent tank/bottle, the pressure washer can be used to apply a thick coating of aerated detergent to the areas being cleaned. When using the rotary brush with the pressure washer we recommend the use of personal safety items to reduce the risk of accidental injury. Suitable Uses