🔍 Key Concepts

• How a pneumercator works – it measures liquid level by air pressure in a bubbler tube or balance chamber • What happens if air pressure is not controlled correctly in the system • Effect of blocked orifices vs. open vents on pressure readings

💭 Think About

• Think about which condition would most directly disturb the pressure balance that represents tank level, making the gauge lie even if the tank level is unchanged. • Consider which option would cause a false higher or lower level without actually changing the amount of fuel in the tank. • Ask yourself: which situation would prevent the system from maintaining the small, steady back pressure of air that the pneumercator needs to read correctly?

✅ Before You Answer

• Identify which answer choice would cause loss of proper pressure reference (either by blockage or by letting it bleed off incorrectly). • Decide which valve position or condition would make the system act as if the tank were more or less full than it really is, even though the level stayed the same. • Verify which choice describes a condition that would change the pressure/flow behavior inside the sensing tube or balance chamber, not just a normal shutdown or operating procedure.