TM 10-6640-239-13 4-171 4-73.    REFRIGERATING CIRCULATOR AND BRACKETS. This task consists of: a. Remove b. Install c. Calibrate 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 Lockwashers (4) Rivets, (9) General Safety Instructions WARNING ELECTRICAL SHOCK Before performing any  maintenance actions on electrical equipment, ensure  all electrical power has been turned off.  Failure to comply with this warning may result in serious injury or death. REMOVE Remove Refrigerating Circulator and Brackets.  See Figure 4-67. a. Open cabinets T and U to gain access to hardware. b. Unplug refrigerating circulator (1) from wall receptacle. c. Loosen two clamps (2), tag and disconnect inlet and outlet coolant tubes (3) from refrigerating circulator (1). d. Loosen strap (4) securing refrigerating circulator (1). e. Remove two screws (5), washers (6), lockwashers (7), nuts (8), bracket (9), and refrigerating circulator (1).  Discard lockwasher. f. Remove three screws (10) and bracket (9) from refrigerating circulator (1). g. Remove two rivets (11) and bracket (12). h. Remove two rivets (13) and bracket (14). i. Remove three rivets (15) and bracket (16). j. Remove two screws (17), washers (18), lockwashers (19), nuts (20), and loop strap fastener (21).  Discard lockwasher. k. Remove two rivets (22), loop strap fastener (23), and strap (4).