ENGINEMAN  1  &  C heat to dissolve the DSP when it is transferred to the TSP solution. Remember,  treatment  in  accordance  with  the DSP dosage table will not bring the phosphate level to the upper limit of 400 ppm (400 mg/L) but will only raise it to 300 ppm (300 mg/L). DSP is added to allow a margin for phosphate in case it should become necessary to treat the feedwater only for alkalinity since the addition of TSP to raise alkalinity will also increase its phosphate level. The boiler must never be surface blown if this action will cause boiler water limits to go below the minimum requirements for alkalinity and phosphate, regardless of the chloride level. A 10 percent blowdown will cause the phosphate, alkalinity, and chloride levels to drop by 10 per- cent. There are no “dump” limits for alkalinity or phosphate. From the standpoint of feedwater consumption,  it  is  better  to  secure  and  dump  the boiler when its alkalinity level is 6 epm (6 meg/L) or when its phosphate level is 1200 ppm (1200 mg/L). CHLORIDE.—If feedwater quality is prop- erly  maintained,  a  maximum  concentration  of 10.0 epm (10 meg/L) chloride in boiler water can be  achieved  without  difficulty.  Leakage  of seawater into the feedwater system, or abnormally high  makeup  rates,   will  cause  a  continuous increase in the chloride level of boiler water. Boiler water  chloride  level  is  controlled  by  surface blowdown and by elimination of seawater con- tamination in the feedwater. If a serious seawater contamination  situation  arises,  every  effort  must be made to isolate and correct the source of con- tamination and to limit it to the system already contaminated. If the boiler water chloride level exceeds 30 epm (30 meg/L), more makeup feed is  needed  to  conduct  surface  blowdowns  than  is used in dumping, flushing, and refilling the boiler. For   additional   information   about   boiler water/feedwater  test  and  treatment,  read  chapter 220,  volume  2,  of  the  Naval  Ships’  Technical Manual.  This manual covers such subjects as (1) steam plant water chemistry principles, (2) water requirements  for  propulsion  boilers,  (3)  casualty control,   (4)   quantitative   analysis   and troubleshooting,  (5)  chemical  safety  precautions, (6)   supply   information,   and   (7)   water requirements for auxiliary boilers. HYDRAULIC  SYSTEMS The overall efficiency of the hydraulic installa- tions used to control or drive auxiliary machines is basically dependent upon the size, oil pressure, speed, and stroke of the hydraulic installation. The efficiency of the hydraulic speed gears and the components of the system as a whole will depend upon the care which is given them. Since major repair of hydraulic gear, except for piping and fittings, is generally done in a naval shipyard or by the manufacturers, this section will deal primarily  with  troubleshooting  and  preventive maintenance. Hydraulic transmissions are sturdy, service- proven machines, inspected and tested with such care that casualties seldom occur except as a result of  faulty  assembly,  installation,  or  maintenance. A  correctly  installed  hydraulic  system,  operated regularly and serviced with proper care, will re- tain its design characteristics of power, speed, and control. The need for costly repair and replace- ment will seldom occur if the equipment has been maintained properly. TROUBLESHOOTING Troubleshooting an electrohydraulic system involves  the  systematic  elimination  of  the  possi- ble causes, one by one, until the actual cause of a casualty is found. In attempting to locate the source  of  any  trouble  in  an  electrohydraulic system, remember that all troubles occur in one of   three   categories—hydraulic,   electric,   or mechanical.  Isolating  a  trouble  into  one  of  these categories is one of the main steps in locating the source of trouble. Hydraulic Troubles Casualties in a hydraulic system are generally the result of low oil levels, external or internal leakage,  clogged  lines  or  fittings,  or  improper adjustment of valves and other working parts. Do not disassemble a unit unless you are certain that the trouble exists within that unit. Unnecessary disassembly may create conditions which lead to additional trouble, since dirt may enter an open system. Leaks  are  a  frequent  cause  of  trouble  in hydraulic  equipment.  Generally,  leaks  are  a  result 7-16