latent heat

I'm modeling the transient heat transfer of a cooler with an ice pack in it. How does one accurately model the phase change of the water? Here's what I've tried so far:

 1. Added latent heat property to material card. Used Latent heat = 334 kJ/kg, Solidus Temp = 0, Liquidus Temp = 0

   Result: Error, Solidus and Liquidus temps cannot be equal

 2. Solidus temp = -0.01, Liquidus temp = 0.01

   Result: Analysis ran, but diverged very early in the analysis.