water cooling system for a plasma gun , method for cooling a plasma gun and method for increasing a service life of a plasma gun . the system includes a water cooler structured and arranged to remove heat from cooling water to be supplied to the plasma gun , a controller structured and arranged to monitor a gun voltage of the plasma gun , and at least one flow valve coupled to and under control of the controller to adjust a flow of the cooling water . when the gun voltage drops below a predetermined value , the controller controls the at least one flow valve to increase the plasma gun temperature and the gun voltage .