The L-moments have particular constraints on magnitudes and relation to each other. This function evaluates and L-moment object whether the bounds for L-scale ($\lambda_2 > 0$), L-skew ($|\tau_3| < 1)$, L-kurtosis ($0.25(5\tau_3^2 - 1) \le \tau_4 < 1$), and $|\tau_5| < 1$ are satisfied. The TL-moments as implemented by the TL functions in lmomco are not applicable to the boundaries consulted within this function.
Hosking, J.R.M., 1990, L-moments---Analysis and estimation of distributions using linear combinations of order statistics: Journal of the Royal Statistical Society, Series B, v. 52, pp. 105--124.
Hosking, J.R.M. and Wallis, J.R., 1997, Regional frequency analysis---An approach based on L-moments: Cambridge University Press.