  Binary neutron star (BNS) mergers are one of the proposed origins for both
repeating and non-repeating fast radio bursts (FRBs), which associates FRBs
with gravitational waves and short gamma-ray bursts (GRBs). In this work, we
explore detectability of radio afterglows from BNS mergers and compare it to
the observed radio limits on FRB afterglows. We calculate the afterglow flux
powered by the two components: a relativistic jet and a slower isotropic
ejecta, and quantify the detection probability as a function of the source
redshift, observing time, and flux sensitivity. The model parameter
distributions inferred from short GRB afterglows are adopted, and viewing angle
distributions (uniform spherical, gravitational-wave, on-axis biased) are
assumed to reflect different searching scenario. Assuming that FRBs are not
strongly beamed, we make comparison to FRBs detected with reported radio limits
and find the detection probabilities are 1--10% in general, and hence not a
strong constraint on the BNS progenitor model considering the small sample
number (<10). In particular for some nearby FRBs (e.g. 180916.J0158+65,
190608), we find a high chance of detection (>20% at 10$\mu$Jy sensitivity) for
the isotropic component that would peak around $\sim$1--10 years after the
merger. Therefore a long term radio monitoring of persistent radio emission for
these objects is important.
