2-13. R.O. ELEMENT CLEANING PROCEDURE - cont.
Remove product water hose from product water tank and place in man made lagoon (figure 2-68).
Place brine water hose in backwash water tank.
To prevent damage to equipment, if backwash pump does not prime it may be necessary to loosen vent
plug on backwash pump to purge air. Tighten vent plug when pump is primed.
Start element cleaning. Push ELEMENT CLEANING switch (24, figure 2-5) up to START position.
Release switch. Switch automatically goes to RUN position. Element Cleaning starts.
Within a few seconds, BRINE FLOW indicator (17, figure 2-5) should show a flow of 16 gpm or more.
If pH of water circulating through R.O. elements drops below 3.5, element membranes may be damaged.
After five minutes of operation, check pH (para. 2-15b) of water discharging back into brine tank; it
should be near, but not below, 3.5. If it is not, add another pound of citric acid and stir until all granules
are dissolved (refer to step (8).
Continue checking pH and adding 1 lb. of citric acid at 5 minute intervals until pH of water is near, but
not below, 3.5.
Temperature of solution will rise during element cleaning. At no time should it exceed 120 degrees. If
temperature rises above 120 degrees, stop recirculating citric acid solution
Allow citric acid solution to circulate for 45 minutes. Periodically check the temperature of the water
discharging back into brine tank; use thermometer from storage chest.
Stop recirculation by pushing the ELEMENT CLEANING switch (24, figure 2-5) down to OFF.
Drainage lagoon should be located down stream of raw water intake to prevent injury to personnel.
Disconnect VENT VESSELS hose from control panel and place in man made lagoon (figure 2-69).