I bought the Tig 200 3 weeks ago and everything was great. I have never tig welded before, but in a short time I was getting the knack of it. My brother who is a welder has been doing all the welding on our project and he loves the welder. The problem came tonight, it acts like the foot pedal is stuck on. As soon as you turn the machine on it is making an arc and gas is coming out. No matter what you do there is constant voltage. I unplug the foot pedal and use the control on the torch and everything works fine, plug the foot pedal back in and you have Constance power. what should I do.