The second element in DirichletCondition
should be a predicate, not a region. Something like this:
phil = NDSolveValue[{Laplacian[v[x, y], {x, y}] == 0,
{DirichletCondition[v[x, y] == 0., Element[{x, y}, boundary1]],
DirichletCondition[v[x, y] == 3000., Element[{x, y}, boundary2]],
DirichletCondition[v[x, y] == 0., Element[{x, y}, boundary3]]}},
v, Element[{x, y}, \[CapitalOmega]elMesh]]