2-13. R. O. ELEMENT CLEANING PROCEDURE.
Figure 2-68. Backwash Water Tank Level.
Connect backwash water inlet hose (figure 2-69) to BACKWASH coupling on control panel.
In the past, when using some source water, brine has been very alkaline, then more citric acid may be
added to start; however, never let pH of brine drop below 3.5 or damage to the R.O. elements will occur.
Mix one pound of citric acid to water in backwash water tank and stir with aluminum paddle until all
granules are dissolved (figure 2-68). (More citric acid may be added later to bring pH of brine near but
not below 3.5.)
Disconnect backwash hose from backwash pump strainer (figure 2-69) and place end of hose at least
25 yards down stream of water raw water source.
Connect vent vessels hose to backwash pump strainer.
Make sure REGULATE PRODUCT FLOW valve (18, figure 2-5) is open (counterclockwise).
Make sure VENT VESSELS gate valve (5, figure 2-61) is open. This valve should remain open at all
times except when producing purified water.
Open gate valve (figure 2-69) between backwash tank and backwash pump (turn handwheel
counterclockwise until it stops).