6. Open the drain valves to the wash and rinse tanks; open the doors and allow the machine to cool. 7. Remove the doors, scrap screens, metal frames, wash and rinse spray arms, pump intake strainer, drain strainer, and splash curtains. Wash thoroughly in the utensils wash sink and rinse. 8. Using hand-dishwashing detergent and water with a nylon-bristled brush, thoroughly clean the inside and outside of the machine. Rinse with clean water to remove  all  loosened  dirt  and  detergent. 9.  Reassemble  the  machine,  close  the  drain  valve to the wash and rinse tanks. 10. Fill the tanks one-half full of water, open the steam valve to the rinse tank and allow the temperature to reach 180°F. 11. Turn the machine on and operate for 5 minutes without  detergent. 12. Turn the machine off, close the steam valve to the rinse tank, and open the drain valves to the wash and rinse  tanks. NOTE: Follow the same basic procedures for the single-tank dishwashing machine with the exception of steps 1 through 4. DESCALING  DISHWASHING  MACHINES The interior of the dishwashing machine and manifold(s)   should   be   inspected   monthly the for accumulation of calcium or lime deposits. If deposits are evident, the machine must be descaled. Descaling the machine should be a part of the PMS and is the responsibility of the foodservice division. The descaling operation must be closely supervised from start  to  finish,  and  personnel  must  wear  face  shields, chemical  safety  goggles,  rubber  gloves,  and  rubber aprons  when  handling  acid. These  descaling  procedures  should  be  followed: 1.  Drain wash/rinse tanks, if applicable. 2.  Install  overflow  pipes,  scrap  trays,  screens, spray manifolds (except final rinse), and curtains (inlet and  discharge  ends  only).  Place  final  rinse  spray manifold on top of scrap tray in wash tank. 3. Shut drain valves. 4. Fill tanks to within 2 inches of top of overflow pipes with clean hot water. 4-22 5.  Add  7  fluid  ounces  of  orthophosphoric  acid  and 1 fluid ounce of rinse additive for each gallon of water per tank. These items can be obtained through the supply  system. 6. Complete filling the tanks and close the doors. 7.  Start  the  machine  and  operate  for  1  hour maintaining  normal  operating  temperatures (150°F- 160°F wash and 180°F-195°F rinse). 8. Stop the machine and open the drain valves. Completely drain acid solution from machine. 9. Inspect the interior of the machine. All the parts should be free of calcium or lime deposits and metal should be shiny. 10. Repeat steps 3 through 8 if necessary. 11. Close drain valves and fill tanks with clean hot water. Add 2 cups of dishwashing compound per tank. 12. Close doors, start machine, and operate for 5 minutes at operating temperatures. 13. Stop machine and completely drain tanks. 14. Refill and flush tanks with clean water to remove all traces of acid and detergent. NOTES:  (1) In the absence of orthophosphoric acid,  only  USDA-approved  chemicals  for  descaling machine  should  be  used, follow  manufacturer’s instruction. (2)  If  tank  capacity  in  gallons  is unknown,  multiply  length  (inches)  times  width  (inches) times depth to overflow (inches) and divide by 231. (3)  Acid  drained  from  the  machine should be disposed of according to local regulations (shore stations and ships in port). GARBAGE  GRINDER Garbage grinders are found in sculleries and deep sinks. They are used to dispose of food from plates, unused food items, and other wet garbage. Always read the operating instructions posted near the grinder before using. To clean the tank, dump a bucket of strong, hot detergent  solution  into  the  tank  and  scrub  the  interior. Rinse by flushing the interior walls with hot water. Clean exterior by scrubbing with hot detergent solution, then rinse.