Boiler Fittings — Identify the Item That Is NOT a Mounting Which of the following is not a boiler mounting (i.e., not a safety/operational fitting fixed to the boiler shell)?

Introduction / Context:
Boiler equipment is categorized into mountings and accessories. Mountings are essential safety and control fittings directly attached to the boiler (e.g., safety valve, water level gauge). Accessories improve performance but are not mandatory for safe operation; examples include air preheaters and economisers.

Given Data / Assumptions:

• Standard fire-tube or water-tube boiler.
• Typical mountings and accessories list.
• Operational definitions used in power plant engineering.

Concept / Approach:
The blow off cock, feed check valve, and fusible plug are classic mountings: they are fixed on the boiler, perform critical safety/control roles, and are required by codes. An economiser is a heat-recovery device placed in the flue-gas path to preheat feedwater; it is an accessory, not a mounting.

Step-by-Step Solution:
List mountings: safety valve, stop valve, water level gauge, fusible plug, blow off cock, feed check valve, pressure gauge.Identify economiser: placed in gas path, not on the pressure shell.Therefore, it is not a mounting.

Verification / Alternative check:
Code requirements (e.g., boiler inspectorate lists) mandate mountings; economiser installation is optional and external.

Why Other Options Are Wrong:
Blow off cock / Feed check valve / Fusible plug: all are mandatory mountings on the boiler shell.

Common Pitfalls:
Confusing “mountings” with “accessories”; location and safety criticality are key differentiators.

Final Answer:
Economiser