What is the function of a trap primer in plumbing systems?

A trap primer is an essential component in plumbing systems designed to maintain the water seal in traps. Its primary function is to prevent the evaporation of the trap seal. Without a proper water seal, sewer gases could escape into the living space, creating health hazards and unpleasant odors.

When water evaporates from the trap due to undisturbed plumbing fixtures, the trap becomes dry. The trap primer automatically adds water back into the trap when it detects that the water level has dropped below a certain point. This ensures that the trap seal remains intact, effectively blocking harmful gases from entering the home.

While maintaining pressure, cleaning pipes, and enhancing drainage are all important aspects of plumbing systems, they do not specifically relate to the protective function that a trap primer serves in preventing the loss of the trap seal. This is why the correct choice is focused on the preservation of the water barrier in plumbing traps.