Powersurvivor 40E (R/O Watermaker) Owners’ Manual:
Membrane Storage, Biociding & Cleaning
(pages 15 - 17)
... Cleaning the membrane
is only necessary if contaminants are deposited on, and adhere to, the membrane surface in sufficient amounts to affect the output of product freshwater. Usually this condition also causes battery current
to increase. There are two main types of such deposits and a different chemical cleaner is needed for each type:
• Organic Growth—usually caused by processing brackish water or failure to properly store a membrane during extended periods of nonuse. Use Alkaline Cleaner.
• Mineral Scale—caused by mineral impurities in the intake water
supply. Use Acid Cleaner.
The only indication that a membrane might benefit from cleaning
is a substantial reduction in the quantity of product freshwater output, all other factors being normal (e.g., battery voltage, salinity, seawater temperature). The best way to detect such a problem is by keeping an accurate log of product freshwater output at known battery voltages. Such a practice is highly recommended.
If you have determined that your membrane needs cleaning and you know the type of deposits (mineral or organic), use the appropriate cleaner. If you do not know the nature of the deposits, try cleaning first with the Alkaline Cleaner and check for improvement in product freshwater output.
If output remains poor, repeat the cleaning process using the Acid Cleaner. Never mix the two types of cleaners! Always flush well with clean water between processes if performing both alkaline
and acid cleaning.
The following directions apply for both types of membrane cleaners:
1. Lift the lever on the cleaning valve on the pump to place it in its “clean” or “up” position
(see Figure 12 - page 15).
2. Discard any dirty seawater in the prefilter assembly. Clean the housing and install a clean filter.
3. Fill a clean plastic container or bucket with one gallon (approximately 4 liters) of clean water.
Freshwater is preferable, but clean seawater may be used if freshwater is not available.
(Caution: Never use chlorinated freshwater. This may damage the membrane.)
4. Mix four spoonful (approximately 40 grams) of either Acid Cleaner or Alkaline Cleaner (not both!) with the water in the container and stir until the cleaner is completely dissolved. The water should be warm, but not over 120̊ F (49̊ C).
5. Turn the lever on the prefilter 3way valve to the alternate intake position. Run the 3/16" alternate intake hose with the strainer attached into the container of cleaning solution.
6. Disconnect the reject brine water hose from its drain (or use a separate length of hose) to route
the reject brine water back into the container of cleaning solution during the following procedure.
7. Turn on the watermaker. Discard any solution coming from the reject brine hose for about 30 seconds. Then run the reject brine water hose back into the container of cleaning solution to allow recirculation of the cleaner.
8. Continue to run the watermaker for about 15 minutes, to assure that the cleaning solution is well circulated through the pump and membrane.
9. Turn off the watermaker and allow the membrane to soak in the cleaning solution for 5 to 10 hours, or overnight. For severe fouling, repeat steps 8 and 9 of this procedure.
10. When the soaking is finished, remove the reject brine hose from the cleaning solution container and run the watermaker again. Discard the first pulses of the reject brine water.
When the reject brine flow becomes cleaner, return the reject brine hose to the cleaning solution container for recirculation.
11. Continue to run the watermaker and recirculate the cleaning solution for another 30 to 60 minutes
12. When cleaning is complete, turn off the watermaker. Reconnect the reject brine hose to its normal drain location.
13. Remove the alternate intake hose and strainer from the cleaning solution and place them into a container of clean, warm (nonchlorinated) freshwater. If freshwater is not available, clean seawater may be used if its temperature is above 68̊ F (20̊ C).
14. Turn on the watermaker and flush warm water through the system for 5 minutes.
If the watermaker will be stored for more than a week (three days in warm climates), it should now be treated with the biocide solution.