< b="" />Boiler Mountings< />
Boiler mountings are the essential components that are attached to the boiler for its proper functioning and safety. They are crucial for the efficient operation of the boiler and play a vital role in ensuring its safe and reliable performance.

< b="" />Options and Explanation< />

a) Air Preheater:
- An air preheater is not a boiler mounting. It is a device used to heat the combustion air before it enters the furnace of the boiler.
- The purpose of an air preheater is to increase the thermal efficiency of the boiler by recovering waste heat from the flue gases and using it to preheat the combustion air.
- While it is an important component in a boiler system, it is not classified as a boiler mounting.

b) Feed Pump:
- A feed pump is not a boiler mounting. It is a device used to supply water to the boiler.
- The feed pump is responsible for supplying water to the boiler at the required pressure and flow rate to maintain the water level in the boiler.
- While the feed pump is an essential component in a boiler system, it is not considered a boiler mounting.

c) Injector:
- An injector is not a boiler mounting. It is a device used to feed water into the boiler.
- Injectors work on the principle of using steam pressure to force water into the boiler against its own pressure.
- Although injectors are commonly used in steam locomotives and other steam-powered systems, they are not classified as boiler mountings.

< b="" />Conclusion< />
None of the given options, air preheater, feed pump, or injector, is considered a boiler mounting. Boiler mountings are specific components that are directly attached to the boiler and are essential for its safe and efficient operation.