Abstract: A trigger having a pawl operates a nozzle valve via a valve stem in a nozzle barrel bore. A spring in the barrel bore normally biases the valve closed. A toothed ratchet lever is pivotally resiliently secured to a trigger guard which protects the trigger from accidental activation. A ratchet tooth in an array of teeth on the lever engages the pawl to hold the trigger in a selected spray position of the valve, the teeth being normally biased disengaged by a second spring. The teeth each have a sharp crest which digs into the trigger in response to the spring bias on the valve stem overcoming the disengagement bias on the ratchet from the second spring. The nozzle is closed by squeezing the trigger to release the ratchet and pawl engagment such that the ratchet lever is pivoted to a disengagment position by the second spring. The assembly comprises metal components in contact with hot fluid but which are thermally insulated with an outer casing spaced from the components by an air gap.