ITEM INTERVAL ITEM TO BE PROCEDURES CHECK FOR AND HAVE REPAIRED OR ADJUSTED EQUIPMENT IS NOT READY NO. B    D    A D    W   M    Q   S A INSPECTED AS NECESSARY AVAILABLE IF · TM 55-1930-209-14&P-17 Table C-1.  Preventive Maintenance Checks and Services ;or Workboat, Lifesaving, and Firefighting Systems (Continued) B - Before D - Daily Q - Quarterly D - During W - Weekly S - Semiannually A - After M - Monthly A - Annually Audi- Stamp  Filled Norm.    Min. Max. Larm Cyl. Cyl. Ring. Ring. Ring. No.* Press.   Press.   Press.   Press.   Press. 1310 1800 1980 400 375 475 2015 2216 540 500 580 13E27 449910 449911 460255 460256 * Audi-Larm Bureau of Mines Approval Number or NIOSH/MSHA Part Number is located on alarm body. 3) To check a demand apparatus, pres- surize the system (1200 psig mini- mum), close the cylinder valve, open the by-pass valve slightly to permit the air to bleed out of the system, and observe the drop in pressure on the regulator gauge and the point at which the alarm rings.  When the air is completely exhausted, close the by- pass valve. s. Check the Diaphragm Function.  Remove Diaphragm the breathing tube and check that the leaks. cylinder and the regulator valves are closed and that the system is not pres- surized: 1) Gently INHALE through the regulator outlet and hold for about 10 seconds. If the negative pressure is maintained, there is no leakage. 2) Gently EXHALE through the regulator outlet for about 10 seconds.  If the positive pressure is maintained, there is no leakage. 3) The regulator outlet should be sani- tized after testing.  Do not use the apparatus if air flow through the regu- lator is detected in either test. C-29