4Th Class Power Engineering B2 104

Front 1

A condensate receiver low level cut-off switch will:A) act to open a make-up solenoidB) stop the feedpump thereby preventing damage to itC) act to close boiler fuel valve(s)D) sound an alarmE) cause the make-up valve to close

Back 1

B

Front 2

A feedwater make-up system should:A) utilise demineralisersB) utilise a deaeratorC) be able to satisfy normal firing needsD) always be softened waterE) be able to satisfy the needs of at least one boiler in a multiboiler plant

Back 2

C

Front 3

An electric feeder valve will:A) eliminate the need for a low-water fuel cut-offB) prevent a low-water tripC) open before the low-water cut-off line is reachedD) require manual action to openE) open after the unit trips on low-water

Back 3

C

Front 4

A Hartford loop will:A) eliminate the need for venting a steam heating systemB) ensure continuous circulation of a hot water systemC) prevent steam from entering a steam pressure gageD) prevent boiler water level from going below the LPWLE) prevent the draining of an expansion tank

Back 4

D

Front 5

The three-wire (double-pole) switch is usedA) as a control switch to open the feedwater control valveB) as a cut-out switch for the fuel valve and as an alarm switchC) as a switch to control the operation of the feedwater pumpD) all of the aboveE) none of the above

Back 5

B

Front 6

The result of a condensate receiver, which is too small could be:A) high boiler water level(s)B) loss of condensate to the sewerC) loss of make-up waterD) unacceptable high steam pressuresE) low make-up water flow rates

Back 6

B

Front 7

Neutralising amines:A) raise the pH of condensateB) lower the pH of boiler waterC) eliminate boiler pittingD) can cause return groovingE) absorb carbon dioxide

Back 7

A

Front 8

Equalising lines on a condensate receiver float chamber:A) will dampen level fluctuationsB) keep receiver level equal to boiler levelC) maintain make-up flow equal to condensate flowD) eliminate the need for a make-up level control valveE) maintains equal flow of condensate to multiple boilers

Back 8

A

Front 9

As a general rule, the volume of a condensate receiver tank in a heating boiler system should be size to the equivalent of the water evaporated by the boiler in a __________.A) 10 to 15 minutes period at normal loadB) 10 to 15 minutes period at full loadC) 20 to 30 minutes period at normal loadD) 20 to 30 minutes period at full loadE) 30 to 40 minutes period at low load

Back 9

C

Front 10

The feedwater supply to most steam heating boilers is usually controlled by a A) diveterB) return trapC) float switchD) Hartford loopE) gauge glass

Back 10

C

Front 11

Which of the following is true about a well balanced steam heating system?A) the amount of condensate returning from the heating system is greater than the amount of steam leaving the boilerB) the amount of condensate returning from the heating system is less than the amount of steam leaving the boilerC) the amount of condensate returning from the heating system is equal to the amount of steam leaving the boilerD) the condensate return is normally not steadyE) the low-water cut-off is not required

Back 11

C

Front 12

Dissolved oxygen in condensate:A) will cause pitting in a boilerB) can cause pitting on the return linesC) causes grooving of the condensate linesD) cannot be removed with chemicalsE) necessitates the installation of a deaerator

Back 12

A

Front 13

When a boiler equipped with a combination feedwater control and low-water cut-off device shuts down due to a low-water condition:A) the feedwater flow will also stopB) level must be restored to above the cut-off line before the unit can be restartedC) it can be restarted by simply resetting the cut-off switchD) a manual reset switch must be usedE) a prepurge will not be necessary

Back 13

B

Front 14

Many heating boilers are equipped with a second source of water supply ( usually city water ) that starts feeding water into the boiler whenA) the water level reaches the cut-in level of the feedwater pumpB) the burner flame goes outC) the normal source of supply is either insuficient or fails altogetherD) low-water cut-off switch opensE) boiler shuts down

Back 14

C

Front 15

A float operated mechanical feeder valve should:A) be a normally closed valveB) open just after the low-water cut-off switch opensC) be located above the water columnD) not be deemed a stand-by deviceE) not open until the level is well below the feed pump cut-in level

Back 15

E

Front 16

A Hartford loop is used on boilers to preventA) water level from getting too highB) steam pressure from getting too highC) scale formation on the heating surfaceD) overheatingE) feedwater from entring the boiler by gravity

Back 16

D

Front 17

The two common gaseous impurities found in condensate areA) O2 and N2B) N2 and airC) O2 and CO2D) CO2 and COE) O2 and H2

Back 17

C

Front 18

Because of variations in flow rate, nearly all large steam heating plants utilise:A) an economiserB) a deaeratorC) a condensate receiverD) multiple boilersE) steam pressure regulating valves

Back 18

C

Front 19

In nearly all LP steam heating systems the feedwater:A) is usually condensateB) requires daily close scrutiny of chemical valuesC) is a high make-up percentageD) must be deaeratedE) requires preheating in an economiser

Back 19

A

Front 20

In a float switch mounted on a low pressure steam boiler, the floatA) controls the steam pressureB) control the condensate flow rateC) follows the changes of the boiler pressureD) follows the fluctuation of the boiler water levelE) shuts down the boiler when the feed pump cut-out level is reached

Back 20

D

Front 21

When one of the boilers requires water in multiple boiler heating plantsA) its float operated control switch opens, energizing the motorized valve in the feedwater branch line to the boilerB) its float operated control switch closes, energizing the motorized valve in the feedwater branch line to the boilerC) its float opearted control switch closes an attached pump starting switch and then closes the motorized valve in the feedwater branch line to the boilerD) its float opearted control switch opens an attached pump starting switchE) none of the above

Back 21

B

Front 22

In multiple boiler heating plants, the feedwater pump supplying more than one boiler at the same time will be shut down byA) the first opened motorized feedwater valveB) the last opened motorized feedwater valveC) the first closed motorized feedwater valveD) the last closed motorized feedwater valveE) the low-water cut-off

Back 22

D

Front 23

The cut-out level of the feedwater control isA) the level at which the cut-out switch opensB) the level at which the supply switch closesC) the level at which the supply switch starts the feedwater pumpD) the highest opearting level of the water in the boilerE) the lowest opearting level of the water in the boiler

Back 23

D

Front 24

The boiler must be equipped with a second low-water cut-off whenA) the first device is also used to control the feedwater flowB) the auxilliary water supply is not able to maintain a safe water level in the boilerC) the normal source of supply is either insuficiaent or fails altogetherD) the second source of supply is controlled by an electric feeder valveE) the second source of supply is controlled by a mechanical feeder valve

Back 24

A