According to wikipedia Ca(HCO3)2 has the following solubility values:
16.1 g/100 mL (0 °C)
16.6 g/100 mL (20 °C)
18.4 g/100 mL (100 °C)
So I assume Ca(HCO3)2 would precipitate beyond this level. However, the wikipedia page for calcium bicarbonate states that attempts to prepare compounds such as solid calcium bicarbonate by evaporating its solution to dryness invariably yield instead the solid CaCO3:
Ca(HCO3)2(aq) → CO2(g) + H2O(l) + CaCO3(s)
which leaves me wondering if, when the solution is saturated beyond ~16-18 g/100 mL, a precipitate of Ca(HCO3)2 will exist in solution? or if it also dissociating beyond that point while still in solution?