  In this work we study the viable parameter space of the scalar sector in the
type-II seesaw model. In identifying the allowed parameter space, we employ
constraints from low energy precision measurements, theoretical considerations
and the 125-GeV Higgs data. These tools prove effective in constraining the
model parameter space. Moreover, the triplet also offers a rich collider
phenomenology from having additional scalars that have unique collider
signatures. We find that direct collider searches for these scalars can further
probe various parts of the viable parameter space. These parts can be
parametrized by the electroweak scalar triplet vacuum expectation value, the
mass splitting of the singly- and doubly-charged scalars, and the
doubly-charged Higgs mass. We find that different regions of the viable
parameter space give rise to different collider signatures, such as the
same-sign dilepton, the same-sign $W$ and the multilepton signatures. By
investigating various LEP and LHC measurements, we derive the most updated
constraints over the whole range of parameter space of the type-II seesaw
model.
