system  should  be  secured  and  all  valves  closed  to prevent movement of this coolant. You  should  start  at  the  highest  point  in  the waveguide  system  and  work  down  to  the  flooded  area of the waveguide. By proper isolation of the flooded waveguide, the extent of repairs can be minimized. Ensure that you do not have trapped coolant in the dry-air lines. Electrical power should be secured and tagged out to prevent a shock hazard because of water that  has  spilled. CLEAN-UP  PROCEDURE First drain the contaminated waveguide by opening the  waveguide  at  convenient  points.  Next,  remove  the components to a clean work area, being careful not to damage them. You should mark each piece to indicate its  location  and  position  so  that  it  can  be  properly reinstalled. Each section of waveguide has to be cleaned by scrubbing it inside and out with hot soapy water. Long sections of waveguide can be cleaned by pulling a clean lint-free rag through each section. A soft cotton cord (not waxed lacing cord) can be used to accomplish this. The rag should be pulled through each section in both directions.  You  must  use  extreme  care  to  avoid  damage to  such  things  as  attenuator  vanes  (thin  glass)  or termination   load   pieces   inside   the   waveguide components. Some  waveguide  components  are  epoxyed  together, and it may not be possible to disassemble them. After cleaning components of this type with hot soapy water, rinse each piece with hot fresh water and then with hot distilled water. Dry each component, and then inspect the interior for damage with a very bright light. (Do NOT use a flashlight because it is not bright enough.) In some cases, the removal, installation, and calibration of  balanced  waveguide  runs  in  the  antenna  are considered  beyond  ship’s  force  capability.  This  is because of the special tools and test equipment required. The waveguide should be reassembled with new gaskets.  Also,  all  damaged  or  broken  components should  be  replaced. Purge   all   air   lines   before reconnecting to the waveguide. After assembly, the waveguide should be purged with dry air for several hours. This is done before the use of the waveguide to ensure the removal of all moisture. Also, before the use of waveguides, you should inspect other water-cooled components for possible deterioration. By completing this step, you can prevent a   reoccurrence   of   waveguide   flooding   caused   by oxidation or dirt buildup on the coolant side of the high-power  components. COOLING SYSTEM MAINTENANCE RESPONSIBILITY The most important responsibility that you have that will  extend  the  life  of  the  cooling  system  components and increase the reliability of the cooling system is how you schedule and perform preventive and corrective maintenance according to the Planned Maintenance System   (PMS). Properly   performed   preventive maintenance  drastically  reduces  the  amount  of corrective  maintenance  necessary. When   cooling systems are neglected, they deteriorate very quickly. To restore   the   cooling   system   back   to   its   proper performance, you may have to undertake extreme and costly  repairs. The PM responsibility of the cooling system varies from one system to another, On some systems, you will find that the engineering department has the total responsibility   of   preventive   and   corrective maintenance. On other systems, you’ll find that you, (the ET), share the maintenance responsibility jointly with the engineering department. In these situations, the ETs would probably perform the  preventive  maintenance  and  the  engineers  would perform   the   corrective   maintenance   on   major components. On those cooling skid systems (such as the SPS-49 radar) that are the sole responsibility of the ETs, you will be assigned the responsibility of maintaining the cooling system. Employing both preventive and connective maintenance   procedures   in   accordance   with   the maintenance  requirement  cards  (MRCs)  maximum operation and dependability of the cooling system can be achieved. SUMMARY In this chapter, you have been introduced to the various  types  of  cooling  systems  for  electronic equipment. You have studied the function and operation of major components within the liquid ceding system. These topics have provided you with the fundamental knowledge  of  their  operation  so  that  after  some hands-on   training   you   can   maintain   them   with confidence. For a more detailed explanation of specific equipment  or  system,  consult  the  manufacturer’s technical  manual. 1-26