You'll find Triacs in gas pumps, they are used to turn on relays for submerged pumps. From my experience, if you cross phase them(short 220 across them) they aren't very tough and easily get projected from the circuit board [Linked Image]..

In my application, it pays to have a wiggy to use in diagnosis as the triacs pass voltage even when not active. A digital meter can mess you up if not familar with this.