TM   10-6640-216-13&P Table 2-11. Operator Preventive Maintenance Checks and Services - continued B - Before A - After M - Monthly D - During W - Weekly Interval Procedures Item Check for and have Equipment is Item to Be repaired  or  adjusted Not Ready/ No. B D A W M Inspected as  necessary. Available If: 23 Air Plenum a. Check that air filters Air filters are dirty. and Damper are clean. Assemblies b.  Verify  that  air Air dampers do not dampers  in  plenums position  properly. open when purge cycle  is  initiated. c.  Verify  that  air Plenum not mounted plenum is mounted properly or air leaks properly  to  ECUS  and are  apparent. that no air leaks are apparent. Laboratory Interior Curbside Wall 24 RVP Gages Inspect face for cracked Glass damaged. or broken glass. 25 Emergency Test  emergency  light  by Emergency  light  does Light pressing  TEST  switch. not come on. 26 First Aid Kit    Check kit for missing Contents are low. contents. 27 Exhaust Check that blower cord is Blower plugged  into  convenience outlet. Laboratory Interior Ceiling 28 Ceiling Inspect for burned out Lights fluorescent  lamps. Replace as required. 2-27