The compressibility compensation factor depends on the fluid. As there are too many fluids, this can be looked up online (natural gas has a 0.5% correction in volume per 100psi under normal pressure and temperature conditions). Various fluids have different compressibilities at different pressures. Eldex pumps allow you to adjust for compressibility by setting the compressibility compensation factor. The default setting is 4. The maximum setting is 60. Each increment increases motor speed by approximately 1%.
