TM 55-1930-209-14&P-19 Table 7-2.  Preventive Maintenance Checks and Services for Compressed Air 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     Oil Level a. Check oil in sight glass on compressor: Oil level low. 1)   Barge 1 - If oil cannot be seen in sight glass, remove oil cover nut in center of air intake assembly.  Pour oil, one pint at a time, until level is at halfway mark on sight glass.  DO NOT overfill. Use nondetergent, rust, and oxidation inhibiting industrial oil with viscosity equivalent to SAE 20, 20-90°F or SAE 10,90°  +. CAUTION On barges 2 and 3 air compressors, NEVER allow oil level to fall more than 1/8 in.  below full level mark on sight glass. 2)   Barges 2 and 3 - Oil level should be up to full mark on sight glass.  To add oil, unscrew oil plug to left of sight glass and add nondetergent, rust, and oxi- dation inhibiting industrial oil with a viscosity equivalent to an SAE grade 20 weight motor oil.  Add oil to full level mark on sight glass.  DO NOT overfill. Replace oil filter plug. NOTE EXTENDED SHUTDOWN Follow procedures e through k for extended shutdown of 12 hours or more. b. Turn AUTO-MANUAL switch on electric controller to MANUAL. c. Push electric controller STOP button. d. Close main supply valve on forward end of receiver by turning handle at right angle to pipe. 7-12