Q.

The principal function of a stop valve is to

• AControl the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
• BEmpty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
• CPut off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
• DIncrease the temperature of saturated steam without raising its pressure