TM 55-1930-209-14&P-19 Table 16-4.  Preventive Maintenance Checks and Services for Ventilation, Heating, and Air Conditioning System (Continued) B - Before D - Daily Q -  Quarterly D - During W - Weekly S -  Semiannually A - After M - Monthly A -  Annually INTERVAL ITEM PROCEDURES EQUIPMENT ITEM TO BE CHECK FOR AND HAVE IS NOT READY/ NO. INSPECTED REPAIRED OR ADJUSTED AVAILABLE IF B   D   A   D  W  M   Q   S   A AS NECESSARY 3 Fans and Motors WARNING Always make sure that electrical power is OFF before performing any maintenance on electrical systems.  Redtag appropri- ate switches and circuit breakers with: "WARNING - DO NOT ACTIVATE. REPAIRS BEING MADE." Observe all safety precautions listed at the beginning of this manual. • a.      Visually inspect fans and motors for dam- Fans or motors age. damaged. • b.      Check fan blades for sufficient cleanli- Fan blades do not ness and clearance.  Clean as necessary. have sufficient clearance. • c.   Check that electrical connections are tight.  Tighten or repair as necessary using insulated tools. • d.      Listen for and check any fan or motor which indicates a motor overload condi- tion or unusual vibration which could result in or be caused by bad bearings, broken impeller blades, or housing shut- down and notify shift leader for repair or replacement. • e.     Visually check deckhouse roof fans for corrosion or damage.  Repair as neces- sary. • f.   Check all fans and motors for rust and corrosion.  Remove with wire brush and paint as necessary in accordance with TB 43-0144.  Do not paint threads or labels. 16-13