A differential pressure gauge for measuring a difference in pressure present between a low pressure portion of a fluid and a high pressure portion of the fluid, the differential pressure gauge comprising: - a cylinder including an opening extending in an axial direction of the cylinder; - a housing including an opening (31; 32, 33; 34; 35) extending in an axial direction of the housing, wherein the cylinder is received in the opening (31; 32, 33; 34; 35) of the housing; characterized in a piston extending in an axial direction from a first end of the piston having a visual indicator to a second end of the piston having a remote indicator, the first end of the piston slidably disposed in the cylinder and in fluid communication with the high pressure portion of the fluid and the second end of the piston slidably disposed in the housing and in fluid communication with the low pressure portion of the fluid; - a sensor configured to determine a presence of the remote indicator when the remote indicator is within a sensing range of the sensor; - a sensor positioning mechanism for adjusting a position of the sensor with respect to the axial direction of the housing, the sensor being coupled to the sensor positioning mechanism, and - a mounting plate disposed adjacent the housing, the mounting plate including a slot extending longitudinally in a direction parallel to the axial direction of the piston, a portion of the sensor positioning mechanism being slidably disposed within the slot, wherein a plurality of indicia is disposed on the mounting plate adjacent the slot, each of the indicia spaced from an adjacent one of the indicia in the longitudinal direction of the slot, wherein the sensor positioning mechanism includes a target pointing at one of the indicia disposed on the plate, wherein sliding movement of the sensor positioning mechanism within the slot causes one of the indicia and the target to vary, wherein each of the indicia corresponds to a user selected value of the difference in pressure present between the low pressure portion of the fluid and the high pressure portion of the fluid at which the presence of the remote indicator is sensed by the sensor, wherein the cylinder is formed from a transparent material to provide visual access to the visual indicator of the piston, and wherein the sensing of the presence of the remote indicator by the sensor corresponds to the difference in pressure present between the low pressure portion of the fluid and the high pressure portion of the fluid being at a pre-selected value. - a cylinder including an opening extending in an axial direction of the cylinder; - a housing including an opening (31; 32, 33; 34; 35) extending in an axial direction of the housing, wherein the cylinder is received in the opening (31; 32, 33; 34; 35) of the housing; - a sensor configured to determine a presence of the remote indicator when the remote indicator is within a sensing range of the sensor; - a sensor positioning mechanism for adjusting a position of the sensor with respect to the axial direction of the housing, the sensor being coupled to the sensor positioning mechanism, and - a mounting plate disposed adjacent the housing, the mounting plate including a slot extending longitudinally in a direction parallel to the axial direction of the piston, a portion of the sensor positioning mechanism being slidably disposed within the slot,