How do you say booster pump?
booster pump... bomba de aumento? A booster pump is a pump that is installed in-line in a water system in order to increase the pressure and pumping rate of water within the piping.
3 Answers
In technical descriptions this is usually called a "bomba presurizadora". Look here.

One choice might be
bomba reforzadora
How about
Aumentador de presión.