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Power Engineering > Unit 21. Heating Boilers > Flashcards

Unit 21. Heating Boilers Flashcards

1
Q

What are the two basic types of heating boilers

A

Low pressure steam boilers and hot water boilers

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2
Q

Heating service uses what type of boiler

A

Fire tube

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3
Q

Three reasons why industrial type water tube boilers are seldom selected for low pressure heating plants

A

Higher cost, closer supervision required, better water treatment requirements

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4
Q

List the advantages of a water tube boiler having serpentine shaped tubes

A

Efficient heat transfer, tube design eliminates expansion and contraction stresses, easy replacement of tubes

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5
Q

List the three main structural configurations for water tube boilers

A

A type, o type,and d type

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6
Q

A popular boiler used in residential and commercial hot water heating systems

A

Copper tubular boiler

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7
Q

Two types of cast iron sectional boilers

A

Horizontal and vertical

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8
Q

Short steel pipe sections machined to a taper on both sides and fitted into adjacent sections

A

Push nipples

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9
Q

List the advantages of cast iron sectional boilers

A

High resistance to corrosion, ease of assembly, choice of assembly location, possibility of enlarging boiler

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10
Q

To be classified as a low pressure steam heating boiler, the operating pressure must not exceed

A

103kPa

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11
Q

To be classed as a hot water heating boiler,the op temp of the water must not exceed

A

121 C and 160 kPa operating pressure.

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12
Q

Three methods of oil gun atomization

A

Air or steam (low pressure); mechanical ( high pressure); centrifugal

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13
Q

Which fittings are required on a hot water boiler.

A

Thermometer, safety relief valve, blow off or drain valve.

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14
Q

In hot water heating boiler systems, the gauge glasses are normally fitted to

A

Expansion tanks

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15
Q

For the scale on the steam gauge of a heating boiler, the travel of the pointer from 0-200kPa shall be at least

A

75mm

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16
Q

An essential fitting between the boiler and steam pressure gauge

A

A siphon

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17
Q

A solenoid type gas fuel valve

A

Is held closed by the fuel pressure

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18
Q

At what pressure should a hot water heating boiler operate if the relief valve is set to 750kPa

A

562 kPa. (750 - .25%)

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19
Q

What are required on all oil storage vessels

A

Air vents

20
Q

Scales on a pressure gauge for a steam heating boiler shall be graduated between

A

200 -414 kPa

21
Q

A relief valve is placed on the discharge of a fuel oil pump

A

So burner design pressure is not exceeded

22
Q

Oil storage systems must be installed according to

A

NFA code, local bylaws and codes, CSA 139

23
Q

What fitting is required in the feed water line adjacent to the boiler before the stop valve

A

A check valve

24
Q

When a closed tube expansion tank on a hot water boiler is completely filled with water and the water in the system is raised in temp so that it expands, the result will be that

A

The pressure build up opens the safety relief valve

25
Q

The working medium in a dead weight tester is

A

Medium weight oil

26
Q

The most important rule in safe operation of a steam heating boiler is

A

Keep the water level in the boiler at a proper level

27
Q

When starting up a cold heating boiler, if it is fired too fast damage can be caused by

A

Uneven expansion, thermal shock

28
Q

The feed water pipe, before entering the boiler, must contain

A

A check valve and stop valve

29
Q

As far as boiler capacity is concerned, the mechanical designer has two choices

A

Use 1 or 2 large boilers; connecting multiple smaller boilers in parallel

30
Q

A gradual increase in stack temp is an indication of

A

Unclean heating surfaces

31
Q

Auto fill valve on a hot water heating boiler

A

Operates in accordance with system pressure

32
Q

Boiler blowdown piping must be

A

Full size to the point of discharge

33
Q

The part of an air atomizing burner that imparts a turning motion to oil is the

A

Swirler

34
Q

The combustion chamber of a serpentine tube water tube boiler is

A

Located below the tubes

35
Q

On low pressure steam boilers, the boiler outlet valves are usually of what type

A

Gate valves due to their low resistance to flow

36
Q

Rust in the gauge glass is an indication that

A

Corrosion of internals

37
Q

Maximum operating temperature of a hot water boiler is

A

121 C

38
Q

Air atomizing burner utilizes air pressure of approximately

A

100 kPa

39
Q

For a relief valve pop test, boilers operating above 414 kPa are allowed +/-

A

5%

40
Q

For hot water boilers operating up to 414kPa, a pressure relief valve opening pressure variation may be as much as

A

20 kPa

41
Q

A steam boiler is blown down to

A

Discharge sediment and scale forming solids from the boiler

42
Q

Explain how the oil flow to a modulating pressure atomizing atomizing oil burner is regulated

A

A constant supply of oil is pumped to the burner, to maintain the oil pressure in the burner nozzle,but a return passage allows some of the oil to be bled off and returned to the fuel tank. A control valve in the return line regulates the return oil flow and therefore the flow of the oil to the furnace

43
Q

Two methods of lighting oil burners on packaged boilers using electric ignition

A

Electrode ignition, spark plug ignition

44
Q

Define “puff back “ associated with delayed ignition

A

Weak ignition, improper adjustment of the electrodes,poor insulation may cause delayed ignition resulting in a puff back. A puff back is caused by a larger than normal amount of combustible mixture in the furnace which, when ignited, builds up a momentarily high pressure and blows back into the boiler room

45
Q

List the minimum information that must be stamped on a boiler fitting

A

Manufacturer or trademark, service designation, material designation

46
Q

Code requirements for steam heating boilers regarding minimum and maximum safety valve seat

A

Must not be smaller than 1/2” (12.7mm) or larger than 41/2” (110mm)

Power Engineering (7 decks)

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