Spectra Watermakers Catalina 340 Z, Installation And Operating Manual

Page: 61 / 90

61
PREFILTERS
During normal operation, the feed water is filtered in two stages. First it passes through a fine
mesh metal sea strainer, which protects the boost pump from foreign materials and sea crea-
tures. After passing through the boost pump, the feed water passes the filter housings con-
taining the 5 micron element, removing very fine particles that could damage the feed pump
or Clark Pump and shorten membrane life. An additional carbon filter prevents the entrance of
chlorine during fresh water flushing (see next page).
Pre-filter maintenance 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 biologically fertile near-
shore waters the pre-filter will plug up, water production and quality will drop, and the system
pressure will change dramatically. In blue water conditions the pre-filter may only need to be
changed every week or two.
When operated for 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. The decaying
plankton and bacteria 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 higher latitudes. If handled gently and
changed regularly before they get too smelly, filters can be cleaned several times. (See
Maintenance, page 50.)
Our filter element part numbers are FT-FTC-XX, where the last digits indicate the micron
rating. FT-FTC-5 is for a 5 micron element, FT-FTC-20 is a 20 micron element. The optional oil/
water separator is FT-FTC-OW.
5 Micron
20 Micron Optional Oil/Water Separator