Spectra Watermakers Newport 1000, Installation & Owner'S Manual

Page: 54 / 70

54
OP-4 FRESH WATER FLUSH
The purpose of the fresh water flush is to replace the sea water in the watermaker with fresh
water whenever the system is not operating. The Auto Flush Mode changes the fresh water
every five days if the system has been idle that long. The watermaker will last longer and
operate better if it is always kept filled with fresh water between uses.
Most spectra watermakers are equipped with a fresh water flush module. This module in-
cludes a 50 micron filter to filter out abrasive particles in the feed water that might damage
the feed pump, a charcoal filter to remove any chlorine in the fresh water that might damage
the membrane, an electrically operated valve and a check, or “one way”, valve. The electri-
cally operated solenoid valve opens during the fresh water flush allowing the boats pressur-
ized water system to supply water to the system. The check valve prevents the fresh water
from going out backwards through the sea strainer and sea cock. The charcoal filter has a
maximum flow rate of 1.5 gallons per minute (6lpm) so the feed pump is operated at a re-
duced speed on some models, or is cycled on and off on other models, to avoid exceeding
this flow rate.
If the ship’s water system is unable to provide flush water at the required flow rate, sea water
will be drawn in to make up the difference. This will cause the flush water to be brackish,
and ineffective in preserving the watermaker. At initial startup the fresh water flush system
should be tested by taking a sample of the brine discharge water just as the flush cycle is
ending. This water should not taste salty, and should read less than 1000 ppm on a digital
tds meter. The flush cycle can also be tested by closing the sea cock during the flush cycle.
If the MPC-3000 display gives a CK SEA STRAINER alarm this means that the fresh water
supply is insufficient. In this case it is very important to either increase the water supply or
adjust the feed pump flush speed as shown in the System Startup instructions.
Because the pre-filters trap the plankton in the feed water they can be subject to “going an-
aerobic” or starting to smell like rotten eggs, as the trapped plankton decay. For this reason
it is advisable to always put in clean elements if the unit is going to be left on Auto Flush
Mode. In daily or regular use the fresh water flush after each shutdown will help prevent
this problem, but in excessively warm or fertile waters the pre-filters will need regular atten-
tion.
7/26/04