TM 10-6640-215-13 4-27.  REMOVE/INSTALL MOTOR CONTROLLERS - continued. b. Connect motor controller electrically and remove tags.  Close controller cover. c. Install conduit and strain relief. d. Close appropriate circuit breaker. e. Verify proper operation of equipment. 4-28.  REMOVE/INSTALL ENVIRONMENTAL CONTROL UNIT 18,000 BTU.  | This task covers: a.  Removal b.  Installation INITIAL SET-UP: Tools Required General Mechanics Tool Kit, (Appendix B, Section III, Item 2) Personnel Required Two (2) General Safety Instructions WARNING ELECTRICAL SHOCK Before  performing  any  maintenance  actions  on  electrical  equipment,  ensure  all  electrical  power has been turned off.  Death or serious injury may occur from failure to do this. REMOVAL Remove Environmental Control Unit (ECU) 18,000 BTU.  See figure 4-17. a. Open appropriate circuit breaker located in the Power Panel No.  2 b. Disconnect two ECU input power cables. c. Loosen two clamps to flexible duct connecting ECU and air ducting of semi-trailer van. d. Disconnect drain line. e. Remove four isolation mounting bolts, washers, and isolation mounts. 4-62