Single Action Piston Pump : A piston pump which discharges water only when the piston is moving in one direction. See also: Piston Pump, Double 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}