SYSTEM MAINTENANCE
MANOWNROLH
4-6
U.S. FILTER
G.
Factors to Consider when Cleaning RO Cartridge
1.
Use RO product water for cleaning and rinse solutions.
Use RO product water to prepare cleaning solutions, and as flush water
between each cleaning step. If RO product water is not available, use
softened filtered tap water. Completely flush the system between
applications of different cleaning solutions.
2.
Increase flow rates and decrease pressure.
During cleaning, reject flow rates should be as high as possible without
exceeding the maximum design flow of the system. The reject regulating
valves should be fully opened to minimize transmembrane pressure.
Transmembrane flow keeps foulants within, or on the membrane surface
during cleaning. Optimally, a high flow, low pressure accessory cleaning
pump should be used.
3.
The temperature must not exceed 35
°
C.
The temperature of the cleaning solution must not exceed 35
°
C. It may
be necessary to install a heat exchanger to prevent the temperature from
exceeding 35
°
C. The optimum temperature of the cleaning solution is 25
°
C to 30
°
C. Cold water reduces the effectiveness of the cleaning solution.
H.
Choosing the Correct Cleaning Method
1.
Recirculation Method (try this first)
This is the cleaning method of choice. Recirculate each cleaning solution
through the RO system for 45 to 90 minutes. Recirculation cleaning
requires an accessory recirculation tank and pump. The system is fed
from the tank, and the reject and product lines are diverted to the tank.
The RO system should be placed in the manual flush mode during
recirculation with the inlet pneumatic valve and accessory motorized 3-
way valve open, and the RO pump off.
CAUTION
If the system temperature approaches the maximum recommended
operation temperature during recirculation, shut down the system and
allow it to cool off before continuing the recirculation.
If the cleaning solution becomes highly discolored during recirculation,
discard it and repeat the application. If any cleaning solution becomes
highly discolored during the first application, the soak and flush method
may be more applicable.
2.
Soak and Flush Method
Pump the cleaning solution into the RO system, soak the cartridges for 15
to 60 minutes, then flush the unit to drain. Flush the system until the
cleaning solution exiting the system is clear, or nearly clear. Repeat soak
and flush cycles until discolored solution is no longer being flushed from
the system. Use this method when the recirculation method is not
effective.
3.
Flush Residual Cleaning Agents Using Reduced Pressure
