🔍 Key Concepts

• Multi-stage distilling plant operation – how pressure and vacuum are maintained separately in each stage • Loop seals and air leaks – how they affect vacuum and pressure in individual stages • Brine pump and priming effects – what pressures they influence and in which stages

💭 Think About

• Think about which component or fault would affect ONLY the first stage pressure while allowing the second stage to remain at a satisfactory absolute pressure. • Ask yourself: which option would most likely introduce air or reduce vacuum in just the first stage, without disturbing the second stage? • Consider how a loss of loop seal, priming, or pump failure would typically change brine level, flow, and pressure in BOTH stages, not just one.

✅ Before You Answer

• Verify which fault would directly cause a loss of vacuum / increase in absolute pressure in the first stage only. • Check whether each option would also disturb the second stage pressure; if it would, it’s less likely to be correct. • Confirm your choice is consistent with how air ingress vs. water flow problems behave in a multi-stage evaporator.