Double Action Piston Pump : A piston pump which is designed so that water is discharged on both strokes of the piston, i. e. , when the piston is traveling in both directions. See also: Single Action Piston Pump
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}