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PF-3 PREFILTERS– ShurFlo
Up to four different filters are used on all Spectra Systems using ShurFlo feed pumps to en-
sure that no damaging foreign materials enter the system. There are 2 or 3 filters in the system
to clean the feed water of abrasive materials while the system is in operation, and an addi-
tional filter to prevent the entrance of chlorine during fresh water flushing.
During normal operation, the feed water is filtered in two stages. First it enters a fine mesh
metal sea strainer. This protects the feed pump from damage due to foreign materials and lar-
ger sea creatures. After passing through the pump the feed water enters the filter housings
containing 20 and 5 micron elements. These filters remove very fine particles which could
damage the Clark Pump and shorten membrane life. Some units have only the 5 micron filter.
Cleaning schedules will vary widely depending on how and where the system is used. If large
amounts of feed water are run through the system in a relatively short period in biologically
fertile near shore waters, the prefilters will plug up, the pressure drop across the filters will
rise, production and quality will drop, and the system will sense plugged filters and give a
“
Service Prefilters
” or “
Check Strainer
” alarm if so equipped. Plugged filters can be
cleaned several times by soaking in a bucket, towing behind the boat at moderate speeds, or
cleaning with a hose.
When operated only an hour or two a day in inland or near shore waters, the trapped plankton
will begin to decay in the filters long before the elements plug up, and the bacteria involved in
the decay will cause a “rotten egg” smell in the product water. This decay will set in overnight
in tropical waters, or after a week or two in high latitudes. If handled gently and changed regu-
larly before they get too smelly, filters in this service can last through dozens of cleanings.
In crystal clear blue water conditions the filters may need to be cleaned much less frequently.
The charcoal filter used in the fresh water flush system will not plug up unless you have some
incredibly dirty domestic water in your boat. About six months after installation the charcoal
filter element will lose its effectiveness at removing any membrane-damaging chlorine which
may be present in domestic water. Charcoal filter elements must be replaced every six months
if there is ANY chance that chorine could be introduced into the flush water.
To ensure that filter elements fit properly and remove chlorine effectively, they should be pur-
chased at factory authorized dealers. Our element part number is FT-FTC-XX. The last two
digits indicate the micron rating, e.g. FT-FTC-05 is for a 5 micron element. Charcoal ele-
ments are FT-FTC-CC.
06/03/04
