The Sprayer can accommodate latex paints, but the dip tube must be primed in order to do so. Remove the strainer from the dip tube, hold a rag (or use your finger) over the red insert in the button, block the orifice and push the button down for a second (you will see bubbles in the liquid as the clog of latex is pushed out of the unit). 

If the power unit gets cold, wrap it with a hot towel to bring it to room temperature or the pressure will become too low.