68
Culligan® Series M2 Reverse Osmosis
68
Cat. No. 01023095
7. Choose GO TO OFFLINE from the main menu. Remove wires from terminals 3 and 4 (Pressure switch) and
install a jumper wire across those two terminals.
8. Open the cleaning valve to allow feed water to displace air in the cleaning tubing, then close the inlet water
shutoff valve.
Clean the Tank
1. Choose GO TO RUNNING from the main menu.
CAUTION! If the pump is noisy, cavitation is occurring and the pump will be damaged. Turn the
power switch OFF and check for any obstructions to flow. Reduce the pump pressure
as required to prevent cavitation.
2. Record the pump pressure and measure the product water flow at low pressure. This flow will be used to esti-
mate if cleaning has been successful. Turn the power switch to OFF.
3. Add enough acid to the solution tank until the pH is between 2.0 and 2.5.
NOTE If the foulant to be removed is silt or a biofilm, use phosphoric acid.
WARNING! Acid and Sodium Hydroxide are strong chemicals that must be handled carefully to
avoid injury. Wear protective clothing and have a source of water nearby to flush any
spills.
CAUTION! Local codes may prohibit the discharge of acid and caustic solutions to drain. If
necessary, an extra tank can be used to neutralize the solutions before discharging to
drain.
4. Choose GO TO RUNNING from the main menu. After approximately 5 gallons have been drawn from the solu-
tion tank, Choose GO TO OFFLINE from the main menu.
5. Allow elements to soak for 15 minutes. Choose GO TO RUNNING from the main menu. Draw another 5 gallons
from the solution tank. Choose GO TO OFFLINE from the main menu.
6. Remove the end of concentrate tubing from the drain and place it in the solution tank.
7. Choose GO TO RUNNING from the main menu. Allow the acid solution to circulate for 30 minutes. During recir-
culation, monitor the pH of the solution. If the pH rises above 3.0, add acid to reduce the pH to 2.0.
CAUTION! The temperature of the chemical solution will rise as it is recirculated. If the tempera-
ture exceeds 95°F, turn the power switch to OFF and allow the solution to cool to
prevent damage to the RO elements.
NOTE A plastic gallon jug filled with ice may be placed in the solution to cool it.
8. When 30 minutes have passed, adjust the system pressure to the pressure recorded in Step 9. Measure the
product flow rate, then compare this flow to the flow recorded in Step 9. If cleaning is successful a noticeably
higher product flow should now be observed.
9. Choose GO TO OFFLINE from the main menu. If the cleaning was for removal of hardness scale or iron only,
go to “Finish Cleaning Procedure” on page 69.
Clean Silt or Biofouling
1. If the cleaning was for silt or biofouling, take a 250 ml sample of phosphoric acid solution and carefully add
sodium hydroxide until the pH is at least 12. If the solution turns cloudy, it contains hardness and/or iron.