High Pressure Boilers Chapter 9

The primary function of a combustion control system is to regulate the ___ in a boiler.

• fuel supply

• air supply

• draft

• all of the above

ON/OFF control is used to start and stop a burner ___.

• and modulate the flame to match steam load

• without modulating the flame to match steam load

• based on measured fuel flow

• based on measured draft

A siphon is used to protect an operating pressure control from ___.

• live steam

• water

• air

• gas

An operating pressure control must be connected to the ___.

• main steam line

• main feedwater line

• highest part of the steam side of the boiler

• water side of the boiler below the NOWL

The two settings found on the boiler operating pressure control are used to ___.

• set the operating steam pressure range of the boiler

• eliminate low water

• maintain high and low fire

• warn the operator of flame failure

The combustion blower continues to run after fuel is shut off to the burner during ___.

• postpurging

• prepurging

• synchronization

• ignition

The programmer in an ON/OFF control system is used to ___.

• control the burner firing cycle

• control the boiler operating range

• secure the burner in the event of low water

• regulate the steam flow

To eliminate the danger of a furnace explosion during startup, the programmer must allow ___.

• main flame ignition

• proving of the main flame

• a prepurge period

• a varying steam load

The purpose of the flame sensor in a flame scanner is to prove ___.

• only the pilot

• only the main flame

• both the pilot and the main flame

• the proper boiler water level

The flame sensor is sensitive to ___.

• heat

• temperature

• pressure

• infrared, visible, or ultraviolet light