TM 10-7310-241-12&P 4-4     Change 1 4-8.   PMCS PROCEDURES (Continued) TABLE 4-1.  PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS) Location Item     Interval Item to Procedure   Not Fully Mission No. Check/ Capable if.       Service           1   Monthly    Pressure   a. Test operation of pressure relief Pressure relief valve does not Relief Valve         valve (Paragraph 4-12). seat correctly. Section IV.  UNIT TROUBLESHOOTING PROCEDURES 4-9.  GENERAL Unit troubleshooting is based on malfunctions or failures observed during operator PMCS (Chapter 2, Table 2-1), Unit PMCS (Table 4-1) or operational use of the HWR. 4-10  TROUBLESHOOTING INSTRUCTIONS FOR MODEL RAK-15 ELECTRIC SHOCK. Do not be misled by the term "low-voltage". Whenever possible turn off and disconnect the HWR power supply before performing any work. Potentials as low as 30 V dc can cause severe electric shock or death under adverse conditions. HIGH TEMPERATURES (1). Be aware that normal operating temperatures within the HWR are up to 190 *F (88 'C) and can reach higher temperatures under abnormal conditions. Use gloves or other hand protection as necessary. Unprotected exposure to high temperatures can cause serious burn injuries. FIRST AID. Never work on the HWR unless there is another person present who is competent in administering first aid. The absence of first aid can result in serious personal injury or even death. Refer to FM 21 -11 (First Aid for Soldiers) for appropriate first aid instructions. CAUTION       DISASSEMBLY. Do not attempt disassembly beyond that which          is necessary for unit troubleshooting and maintenance.         Unauthorized disassembly can result in the HWR becoming          non-operational. This troubleshooting flowchart describes typical malfunctions, which are most likely to occur when operating the HWR.  To use the flowchart, commence at the START function and check each set of fault conditions against the observed malfunction.  When matching fault conditions are identified, rectify the malfunction by following the corrective action instructions in the order in which they appear. The flowchart cannot contain all the malfunctions that may occur or all the corrective actions needed to rectify a particular malfunction. If a particular malfunction cannot be identified, or is not cleared by the corrective actions, notify your supervisor. WARNING