Recreational Vehicle (RV) Technician Practice Test

Which instrument is used to measure low pressure systems?

1. Barometer

2. Thermometer

3. A manometer

4. Hydrometer

The correct answer is: A manometer

The manometer is specifically designed to measure low pressure systems, particularly in situations where precision is crucial. It utilizes a U-shaped tube filled with a fluid, typically mercury or water. When pressure is applied to one side, it causes the fluid to move, allowing for a direct measurement of the pressure difference between the two sides. This functionality is particularly valuable for measuring low pressure in gas systems, as it can provide a clear and precise reading in conditions where other devices may not be able to accurately detect low pressure. On the other hand, while a barometer measures atmospheric pressure and can indicate high or low pressure systems in relation to weather patterns, it is not specifically designed for measuring low pressures in confined spaces. Thermometers measure temperature, which is unrelated to pressure measurements, while hydrometers are used to measure the specific gravity of liquids and not pressure at all. This distinction highlights why the manometer is the appropriate choice for measuring low pressure systems.