TM 55-1930-209-14&P-19 Table 9-3.  Preventive Maintenance Checks and Services for Electrical Power Systems(Continued) B -  Before D -  During A -  After H -  Hourly Interval INTERVAL ITEM PROCEDURES EQUIPMENT ITEM TO BE CHECK FOR AND HAVE IS NOT READY/ NO. INSPECTED REPAIRED OR ADJUSTED AVAILABLE IF B   D   A H AS NECESSARY SHIP SERVICE GENERATOR (SSG) SYSTEM WARNING Ear protection must be worn in voids 4 when any generator is operating. WARNING At operating temperatures, engine coolant   is   hot   and   under   pressure.   It also contains alkaline materials harmful to   eyes   and   skin.   To   avoid   personal injury   check   coolant   level   only   when engine is stopped and filler cap is cool enough to be touched by the bare hand. If coolant comes in contact with eyes or skin,   immediately   flush   affected   area with    clean    water    and    seek    medical assistance. CAUTION Sensing element must be submerged in coolant   to   operate.   If   coolant   is   low, engine    can    overheat    and    automatic shutoff    will    not    function    to    prevent damage to engine. 1 10 hrs Engine a. Check engine coolant level-should not be more than ½  in. below filler pipe. Fill with clean, fresh water (low in scale- forming minerals but not softened water)- see table below.  Add cooling system conditioner to water before filling. Condi- tioner should be 3 percent by volume of total coolant capacity (about ½  pint of conditioner per 2 gallons of water). 50% Antifreeze Without Water Content 50% Water Antifreeze Chlorides 100 ppm or less 50 ppm or less Sulfates 100 ppm or less 50 ppm or less Hardness as CaCo3 200 ppm or less 100 ppm or less Dissolved Solids 500 ppm or less 250 ppm or less pH 6.5 or higher 6.5 or higher ppm = parts per million 9-8