The Dwyer Series 475 Mark III intrinsically-safe digital manometer provides positive, negative, and differential pressure measurements, and is used to perform field calibration, monitoring or troubleshooting HVAC systems, performing clean room inspections, air velocity monitoring, and natural gas appliance-line testing. The meter is FM-approved intrinsically safe for Class 1, Div. 1, Group A, B, C, D, T4 hazardous locations. It has an accuracy of + or - 0.5% of full scale at 60 to 78 degrees F, and + or - 1.5% full scale at 32 to 60 and 78 to 104 degrees F. The extruded aluminum case provides durability. The backlit four-digit LCD displays the pressure measurement. The zero function nulls minor pressure differences before measuring. Standard connections accept 1/8" or 3/16" inside diameter (ID) vinyl or rubber tubing. The meter is powered by a 9V battery (included) and automatically shuts off after 20 minutes to preserve battery life.

H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.

Manometers measure the pressure of a liquid or gas. Th