🔍 Key Concepts

• Boiler drum water level behavior when steam demand or firing rate changes • How steam bubbles in the water space affect indicated water level • Difference between mechanical problems (like erratic feed) and normal level responses to load changes

💭 Think About

• Ask yourself: When you suddenly increase or decrease steam flow, what happens to the mixture of water and steam in the drum, and how would that make the gauge glass level appear to change? • Think about whether ‘swell’ and ‘shrink’ are normal, expected reactions of the drum level to load changes, or signs of contamination or malfunction. • Consider which choice best describes a cause that would produce both an apparent rise (swell) and an apparent fall (shrink) in level without actually adding or removing much water.

✅ Before You Answer

• Verify which option refers directly to a change in steam demand or firing rate, not water chemistry. • Check which choice mentions steam bubbles changing volume and how that would affect the apparent level in the gauge glass. • Eliminate any answer that sounds like a water quality or feedwater control malfunction issue rather than a normal dynamic response.