TM 10-6640-238-13 4-20 4-10.    INTRODUCTION a. This section contains instructions covering unit maintenance functions for the Petroleum Laboratory.  Personnel required are listed only if the task requires more than one. b. After completing each maintenance procedure, perform operational check to be sure that equipment is properly functioning. 4-11.    WATER INLET BOX. This task consists of: a. Remove b. Repair c. Install INITIAL SET-UP Tools Required General Mechanics Tool Kit, (Appendix B, Section III, Item 1) Portable Electric Drill, (Appendix B, Section III, Item 2) Twist Drill Set, (Appendix, B, Section III, Item 2) Hand Blind Riveter, (Appendix B, Section III, Item 3) Materials/Parts Required Gasket, (1) Lockwashers, (6) Rivets (21) Rivnut (4) Adhesive, (Appendix E, Section II, Item 3) REMOVE 1. Remove Door Assembly.  See Figure 4-1. a. Remove seven rivets (1) from door assembly (2). b. Unlatch and remove door assembly (2). 2. Remove Water Inlet Box and Gasket. a. Remove gasket (3). b. Remove 14 rivets (4) that secure water inlet box (5) to Mod Lab A (6) and remove water inlet box. 3. Remove Hose Adapters. a. Remove retaining ring with chain (7) from hose adapters (8). b. Remove hose adapters (8). 4. Remove Coupling Assembly. a. Disconnect union (9) from coupling assembly (10). b. Remove four screws (11), nuts (12), and washers (13) that secure coupling assembly (10) to water inlet box (5). c. Remove coupling assembly (10) and gasket (14).  Discard gasket. 5. Remove Direction Valve. a. Remove four screws (15), nuts (16), and washers (17) that secure direction valve (18) to water inlet box (5) and remove direction valve.