Ink reservoir subassemblies for phase change ink can be designed and configured to include at least one structure comprising elements disposed within the ink reservoir. A low pressure resides on the downstream end of the nucleation valve and as the liquid passes the valve, bubble nucleation is initiated, forming the first step in a deaeration process. A dual wall personal floatation device with its over sized inner bladder creates extended midline crossing. Preferably, the direct electrical current is generated at a select frequency profile as a function of time, and with a carrier signal of about 10,000-12,000 hertz. Measures of the second and third currents and measures of the first and second resistors can be used to determine device temperature.