  We investigate monoenergetic gamma-ray signatures from annihilations of dark
matter comprised of Z^1, the first Kaluza-Klein excitation of the Z boson, in a
non-minimal Universal Extra Dimensions model. The self-interactions of the
non-Abelian Z^1 gauge boson give rise to a large number of contributing Feynman
diagrams that do not exist for annihilations of the Abelian gauge boson B^1,
which is the standard Kaluza-Klein dark matter candidate. We find that the
annihilation rate is indeed considerably larger for the Z^1 than for the B^1.
Even though relic density calculations indicate that the mass of the Z^1 should
be larger than the mass of the B^1, the predicted monoenergetic gamma fluxes
are of the same order of magnitude. We compare our results to existing
experimental limits, as well as to future sensitivities, for image air
Cherenkov telescopes, and we find that the limits are reached already with a
moderately large boost factor. The realistic prospects for detection depend on
the experimental energy resolution.
