Back washing tubular filter system -20 degrees F at 150 psi. Filter cannisters Filter cannisters serial # 222638 E1-1 & E1-2. Each filter contains ontains one 2" x 18" wire mesh housing, with a 316 SS woven screen capable of particle containment from 1-1,650 microns. Service lines 3" headers with reducers down to 1.5". Automatic backwash based on preset pressure differential, with a micro processor control system. Manual back wash provisions included. Operators control panel with pilot loights indicating : On Stream, Backwash, Excess Backwash frequency. Manual start/ run/ off switch.