🔍 Key Concepts

• Principle of operation of a pneumercator (air bubbler type level gauge for tanks) • What the purge position of the control handle is supposed to do to the air line and gauge • How supply air pressure and tank back pressure** should appear on the gauge in normal vs. purge conditions

💭 Think About

• Ask yourself: in the purge position, is the gauge sensing tank back pressure, or only the air supply line? How should a healthy system behave? • Consider what would prove that the gauge and air line are intact and not blocked or leaking before you trust the initial level reading. • Think about which option gives an independent confirmation of the actual liquid level in the tank versus only repeating the same instrument’s behavior.

✅ Before You Answer

• Verify what a pneumercator actually measures (air pressure required to bubble through the liquid) and how that relates to level. • Confirm what the purge function does to the sensing line (clearing liquid, isolating or exposing it to supply air). • Check which method/indication would reveal a blocked, leaking, or mis‑zeroed line or gauge, instead of just duplicating a possible error.