Service and Maintenance
69
Cat. No. 01023095
Discard the contaminated acid and prepare a fresh 30 gallons of phosphoric acid solution.Add sodium hydroxide
to the phosphoric acid solution. The pH of the solution should be increased to 11.0-11.5.
NOTE The result is an alkaline solution of tri-sodium phosphate (TSP), a common ingredient in detergents.
2. If the solution remains clear, then direct the concentrate tubing to drain, then choose GO TO RUNNING from
the main menu. Check that the unit is drawing chemical solution.
CAUTION! If the pump is noisy, cavitation is occurring and the pump will be damaged.
Choose
GO TO OFFLINE from the main menu
and check for any obstructions to flow. Reduce
the pump pressure as required to prevent cavitation..
3. After approximately 5 gallons have been drawn from the solution tank, choose GO TO OFFLINE from the main
menu.
4. Allow the elements to soak for 15 minutes. Turn the power switch to ON. Draw another 5 gallons from the solu-
tion tank. Choose GO TO OFFLINE from the main menu.
5. Remove the end of concentrate tubing from the drain and place it in the solution tank. Choose GO TO
RUNNING from the main menu. Allow the alkaline solution to circulate for 30 minutes. During recirculation moni-
tor the pH of the solution. If the pH drops below 10.0 add sodium hydroxide to increase the pH to 11.5.
NOTE If the caustic solution becomes dark brown (like coffee), it probably is saturated with organic material.
Discard the solution and prepare a fresh batch of phosphoric acid and sodium hydroxide.
For more accurate testing, use a Hach Model DE-2 detergent test kit or equivalent to ensure that the
product water is less than 0.05 ppm detergent.
A plastic gallon jug filled with ice may be placed in the solution tank to cool the solution.
CAUTION! The temperature of the chemical solution will rise as it is recirculated. If the tempera-
ture exceeds 95°F,
choose GO TO OFFLINE from the main menu
and allow the solution
to cool to prevent damage to the RO elements.
Finish Cleaning Procedure
1. When 30 minutes have passed, adjust the system pressure to the pressure recorded during low pressure.
Measure the product flow rate, then compare this flow to the flow recorded during low pressure. If cleaning is
successful a noticeably higher product flow should now be observed.
2. Choose GO TO OFFLINE from the main menu. Remove the concentrate and product tubing from the solution
tank and direct them both to drain. Choose GO TO RUNNING from the main menu to draw most of the remain-
ing cleaning solution from the tank.
CAUTION! Do not allow the unit to draw air from the tank, or the pump will be damaged.
3. Choose GO TO OFFLINE from the main menu. Close the cleaning valve, reconnect the wires to the pressure
switch, then open the feed water valve.
4. Choose GO TO RUNNING from the main menu and flush the cleaning solution from the unit for 30 minutes or
until the pH levels of the concentrate water and the product water remain constant.
CAUTION! Soft water must be used to flush the caustic solution, or hardness will precipitate. If
soft water is not available, use temporary portable exchange softener tanks.