Central Plumbing, Heating and ExcavationPlumbing pre-apprenticeship - Helena, MT Central Plumbing, Heating and ExcavationPlumbing pre-apprenticeship - Helena, MTHelena, MTTeam members will gain hands-on exposure to the plumbing trade while developing the skills needed to transition into our Plumbing Pre-Apprenticeship Program. Central Plumbing, Heating & Excavation is a respected mechanical and excavation contractor performing projects throughout Central Montana.