Abstract: Embodiments herein relate to filter restriction indicator (100) for a filtration system. In an embodiment, a filter restriction indicator (100) can have an electronics control cartridge (800) including an internal spacer frame (304), a first circuit board (346), a second circuit board (302) disposed over the first circuit board (346), and a pressure sensor (336) in electrical communication with the first circuit board (346). A filter fluid tube (318) defines a filter fluid channel (348) in fluid communication with the pressure sensor (336). The internal spacer frame (304) can secure the first circuit board (346) at a fixed distance from the second circuit board (302). A lower housing (108) defines an ambient pressure port (310). A cap (102) defines an interior volume (332) into which the electronics control cartridge fits (800).

Abstract: Commercially available filter-monitoring switches suffer from problems related to over sensitivity and reliability. Accordingly, the present inventors have devised, among other things, various embodiments of filter-monitoring switches and related components, subassemblies, methods, and systems. One exemplary filter-monitoring switch includes a diaphragm operably couple to move a conductive element back and forth between a pair of fixed terminals in response to pressure differences across the diaphragm. The conductive element is mounted to an insulative pin of substantially uniform width, and the terminals include leaf contacts that constantly engage the pin or the contacts throughout normal operation of the switch, thereby reducing flexure of the contacts and effectively providing a self-cleaning and self-healing electrical switch.