MAINTENANCE TIPSPOTABLE WATER SYSTEM DRAINING IN COLDWEATHER CONDITIONSIn cold weather conditions, the potable water system must be drainedto prevent damage to the system by ice. To know if it is necessary todrain the potable water system, refer to the water system drainconfiguration table in the AMM 12-24-38. If the bleed air system isoff and the external air temperature is below 0 ¡ãC (32 ¡ãF), the drainvalves must remain open after the potable water system is drained toprevent damage to the potable water system. The cold weathermaintenance procedures for the potable water system are given in theAMM 12-31-38.