As an Engineman, you will be required to operate a submerged-tube distilling plant. Some basic operational practices are as follows:

1. Check the flow rate of the feedwater through the ratosight meter and the flow rate of the distillate through the water meter. Adjust the feed inlet control valve to maintain a feedwater to distillate flow ratio of 3 to 1. (For example, you should have 3 gallons of feedwater to 1 gallon of distillate.) This procedure will help you prevent excessive scale buildup in the unit.

2. When you are operating the unit in seawater temperatures below 85F, adjust the cooling water control overboard valve (using the indication on the ratosight meter) to maintain the evaporator shell temperature at 130F.

3. Maintain the distillate level below the top of the observation windows on the evaporator by adjusting the water meter shutoff valve.

4. Make frequent inspections through the distillate observation windows. Watch for a rise in the feedwater level. (The rise may be caused by an insufficient brine discharge rate.) Check for a malfunctioning brine eductor supply pump or brine eductor. Air leaks in the suction piping will impair (or prevent entirely) the operation of the unit pumps and will be indicated by a consequent rise in brine or distillate levels.

5. Do not operate the unit beyond its rated capacity or above the limit specified for shell temperature. Operation of the unit at higher than rated temperatures will cause rapid scale forma-tion on the heat transfer surfaces.

For additional information, consult the NAVSEA technical manual for your unit.