Spectra Watermakers Farallon 1800, Installation And Operating Manual

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34
Membrane Cleaning
For normal cleaning, the SC-3 Acid Cleaning Compound is used first, then the SC-2 Alkaline
Cleaning Compound. If known bio-fouling is present, the SC-2 may be used first. Use hot water
if possible, up to 120°F (45C) is recommended as it greatly enhances the ability of the cleaners
to do their jobs.
If the history of the system is unknown or has been left “unpickled” for an extended length of
time and biological growth is present, it is recommended that the system is cleaned with SC-2,
using an alternate source of unchlorinated fresh water before the system is run under pressure.
A simple test can be performed to see if biological growth has occurred. Before running the
system, remove the prefilters and examine their condition. If the housings are full of smelly
discolored water, the system was not properly stored. Install clean prefilters if they were bad.
Next check the membrane. Attach the brine discharge service hose and lead to a bucket. Open
the pressure relief valve one turn, and manually run the system for 30 seconds. Examine the
brine water: if it’s discolored and smells bad, perform an SC-2 cleaning with an alternate source
of unchlorinated water before running the system pressurized. If the brine is fairly clean, the
system can be purged, run normally, and checked for performance. Clean the membranes only
if performance is reduced.
Heating the water is preferable. One way to do this is to find a camp stove and use a large
stainless steel pot to heat the solution in. The cleaning solution throughout the system will heat
as it circulates in and out of the pot. An alternative is to heat the one or two gallons of water to
120° on the before mixing in the cleaner and circulating it into the system. Periodically stop and
reheat the solution.
Perform the cleaning procedures while the ship is in acceptable sea water for purging and testing
.

There are two types of cleaners: acid and alkaline. The acid cleaner (SC-3) will remove
mineral scaling. The alkaline cleaner (SC-2) is used to remove biological by-products, oil,
and dirt particles that get past the prefilters. If membrane performance is reduced and they
have not been pickled recently, cleaning with both chemicals is recommended. The acid
cleaner should be used first. If the membrane fails to respond to both cleanings, this is an
indication of another problem with the system, or that it is time to replace the membranes.
Contact Spectra Watermakers before removing a membrane.

The membranes need to be cleaned only when operating pressures have risen more than
10% or the product quality degrades. The leading cause of fouling in marine use is from
biological growth that occurs when the system is left unused without flushing or pickling.
Fouling from mineral scaling can happen during operation under certain sea water
conditions, and from rust. Monitor the product salinity and membrane pressure for higher
than normal readings for the conditions. Other conditions can cause high pressure such as
cold water or high ocean salinity. Low product flow is usually due to blocked or partially
blocked pre-filters, Spectra-Pearson Pump problems, or low boost pressure. Look for all
other causes before cleaning the membrane. Membrane life can be shortened by excessive
cleaning.
The Membranes