  Transiently accreting neutron stars in low mass X-ray binaries are generally
believed to be heated up by nuclear reactions in accreted matter during
hydrostatic compression. Detailed modeling of these reactions is required for
the correct interpretation of observations. In this paper, we construct a
simplified reaction network, which can be easily implemented and depends mainly
on atomic mass tables as nuclear physics input. We show that it reproduces
results of the detailed network by Lau et al. (2018) very well, if one applies
the same mass model. However, the composition and the heating power are shown
to be sensitive to the mass table used and treatment of mass tables boundary,
if one applies several of them in one simulation. In particular, the impurity
parameter $Q_\mathrm{imp}$ at density $\rho=2\times 10^{12}$ g cm$^{-3}$ can
differ for a factor of few, and even increase with density increase. The
profile of integrated heat realize shown to be well confined between results by
Fantina et al. (2018) and Lau et al. (2018).
