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PF-1 PREFILTERS- VANE PUMP SYSTEMS
Five different filters are used on these Spectra Watermakers to make sure that no damaging
foreign materials enter the system. There are four filters in the system to clean the feed wa-
ter of abrasive materials while the system is in operation, and a fifth filter that prevents 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 then passes through a fifty micron pleated cellulose filter. These protect
the vane pump from damage due to abrasion from silt and hard shelled plankton found in the
feed water. After passing through the pump the feed water enters the filter housings contain-
ing 20 and 5 micron elements. These filters remove very fine particles which could damage
the Clark pump and which would shorten membrane life. Note: On Mark two systems there
is no 50 micron filter and the 20 and five are before the feed pump.
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 bio-
logically fertile near shore waters, the prefilters will plug up, the pressure drop across the
filters will rise, product 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 hosing them off.
When operated only an hour or two a day in inland or near shore waters, the trapped plank-
ton will begin to decay in the filters long before the elements plug up, and the bacteria in-
volved 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 regularly before they get too smelly, filters in this service can last through doz-
ens 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 chlo-
rine 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 wa-
ter. Charcoal filter elements cannot be cleaned.
To ensure that filter elements fit properly and remove chlorine effectively, they should be
purchased 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
elements are FT-FTC-CC.
06/03/04
