Do not hold START BACKWASH switch up for more than 5 seconds to avoid
damage to the controls.
(10) When a steady stream of water flows from backwash pump draincock, close draincock.
Mechanical timer is activated within 5 minutes after pushing START
BACKWASH switch up. Solidstate timer will come on immediately.
BACKWASH PUMP ON lamp will come on, pump will start and backwash water
will flow through the multimedia filter and out the waste water hose. The
multimedia filter gage needle will move fully to right. During backwash, the
backwash water flow rate varies automatically from 0 to 70 to 120 gpm while
washing and rinsing.
For the mechanical timer, backwash operation is automatic after the backwash
pump is started and lasts about 15 minutes. With the solidstate timer,
backwash lasts about 13 minutes.
(11) When backwash is complete, BACKWASH PUMP ON Lamp will go off and multimedia gage
will return to 0.
When backwash pump shuts off, turn BACKWASH valve handle upward to left to NORMAL
position. Close valve at brine water supply tank.
(12) Start up the ROWPU after backwash in the normal manner (para. 2-25).
Since the multimedia filter uses brine water to backwash, it should not be
drained or left inoperative following backwash without first flushing with raw
water for 5 minutes. Flush by operating filter normally.
CITRIC ACID FEED. After 20 hours of full operation, feed citric acid solution into filtered water in order
to maintain pH recommended for optimum R.O. process:
Chemicals can cause sickness or even death if extreme care is not taken. Wear
protective devices when working with these solutions.
Put 0.75 pounds of citric acid into CITRIC ACID pail, using citric acid measure.
b. Fill CITRIC ACID pail with 3 gallons of brine.
Stir chemical and brine with wooden paddle, and pour solution into 5 gallon container.
d. While the ROWPU is operating normally, set the citric acid chemical feed pump valve on RUN, and
set chemical feed control knob to maximum setting 10 (Model No. 600-1), 8.5 (Model No. 600-3).
Wait for 10 minutes.