  We analyse the phenomenology of a model of neutrino masses inspired by
$\mathrm{E}_{6}$ GUT unification in which the exotic neutrinos can be present
at low scales. The model introduces vector-like isosinglet down-type quarks,
vector-like isodoublet leptons, neutrino singlets and two $Z'$ bosons. The
seesaw mechanism can be achieved with exotic neutrino masses as low as 100 GeV
and Yukawa couplings of order $10^{-3}$. We find that the lightest $Z'$ boson
mass is required to be above 2.8 TeV, the exotic quark masses are required to
be above 1.3 TeV (810 GeV) if they are collider stable (promptly decaying), and
the exotic lepton mass bounds remain at the LEP value of 102 GeV. The model
also presents a type-II two-Higgs-doublet model (2HDM) along with two heavy
singlet scalars. The 2HDM naturally has the alignment limit enforced thanks to
the large VEVs of the exotic scalars, thereby avoiding most constraints.
