What does an inclined manometer measure?

An inclined manometer is specifically designed to measure low gas pressures, typically in the range of inches of water column (W.C.), which is a common requirement in heating, ventilation, and air conditioning (HVAC) applications. Its design allows for high sensitivity and accuracy in measuring these low pressures, making it especially useful for assessing pressure drops across filters, coils, and other components within a gas furnace system.

The inclination of the manometer beam amplifies the height of the liquid column, allowing for a more precise reading of small pressure differences. The unit is often calibrated for pressure levels not exceeding 2" W.C., which is ideal for applications in gas furnaces where proper combustion and system efficiency depend on maintaining specific pressure levels.

While it’s true that manometers can measure pressure within a certain limit, the inclined manometer's primary function is not suited for measuring pressures beyond this specification. Higher pressure readings would typically require different types of measurement equipment. Therefore, the capability of the inclined manometer to measure pressures above 2" W.C. does not align with its intended use.