Unit 21. Heating Boilers

Question 1

What are the two basic types of heating boilers

Answer 1

Low pressure steam boilers and hot water boilers

Question 2

Heating service uses what type of boiler

Answer 2

Fire tube

Question 3

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

Answer 3

Higher cost, closer supervision required, better water treatment requirements

Question 4

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

Answer 4

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

Question 5

List the three main structural configurations for water tube boilers

Answer 5

A type, o type,and d type

Question 6

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

Answer 6

Copper tubular boiler

Question 7

Two types of cast iron sectional boilers

Answer 7

Horizontal and vertical

Question 8

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

Answer 8

Push nipples

Question 9

List the advantages of cast iron sectional boilers

Answer 9

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

Question 10

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

Answer 10

103kPa

Question 11

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

Answer 11

121 C and 160 kPa operating pressure.

Question 12

Three methods of oil gun atomization

Answer 12

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

Question 13

Which fittings are required on a hot water boiler.

Answer 13

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

Question 14

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

Answer 14

Expansion tanks

Question 15

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

Answer 15

75mm

Question 16

An essential fitting between the boiler and steam pressure gauge

Answer 16

A siphon

Question 17

A solenoid type gas fuel valve

Answer 17

Is held closed by the fuel pressure

Question 18

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

Answer 18

562 kPa. (750 - .25%)

Question 19

What are required on all oil storage vessels

Answer 19

Air vents

Question 20

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

Answer 20

200 -414 kPa

Question 21

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

Answer 21

So burner design pressure is not exceeded

Question 22

Oil storage systems must be installed according to

Answer 22

NFA code, local bylaws and codes, CSA 139

Question 23

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

Answer 23

A check valve

Question 24

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

Answer 24

The pressure build up opens the safety relief valve

Question 25

The working medium in a dead weight tester is

Answer 25

Medium weight oil

Question 26

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

Answer 26

Keep the water level in the boiler at a proper level

Question 27

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

Answer 27

Uneven expansion, thermal shock

Question 28

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

Answer 28

A check valve and stop valve

Question 29

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

Answer 29

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

Question 30

A gradual increase in stack temp is an indication of

Answer 30

Unclean heating surfaces

Question 31

Auto fill valve on a hot water heating boiler

Answer 31

Operates in accordance with system pressure

Question 32

Boiler blowdown piping must be

Answer 32

Full size to the point of discharge

Question 33

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

Answer 33

Swirler

Question 34

The combustion chamber of a serpentine tube water tube boiler is

Answer 34

Located below the tubes

Question 35

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

Answer 35

Gate valves due to their low resistance to flow

Question 36

Rust in the gauge glass is an indication that

Answer 36

Corrosion of internals

Question 37

Maximum operating temperature of a hot water boiler is

Answer 37

121 C

Question 38

Air atomizing burner utilizes air pressure of approximately

Answer 38

100 kPa

Question 39

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

Answer 39

5%

Question 40

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

Answer 40

20 kPa

Question 41

A steam boiler is blown down to

Answer 41

Discharge sediment and scale forming solids from the boiler

Question 42

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

Answer 42

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

Question 43

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

Answer 43

Electrode ignition, spark plug ignition

Question 44

Define "puff back " associated with delayed ignition

Answer 44

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

Question 45

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

Answer 45

Manufacturer or trademark, service designation, material designation

Question 46

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

Answer 46

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