Finals Exam

Question 1

What does a siphon do?

Answer 1

Protects the steam gauge from high temperature

Question 2

What can cause boiler to explode?

Answer 2

Adding hot water to the boiler. Excessive unburned fuel.

Question 3

What are the benefits of water treatment?

Answer 3

Prevent scale and corrosion

Question 4

What are things that cause corrosion and pitting?

Answer 4

Oxygen and Carbon Dioxide

Question 5

How often do you test safety valves?

Answer 5

Monthly?

Question 6

What is the remedy for a cold hydronic coil?

Answer 6

Bleed the air from coil

Question 7

Purpose of the tri-cocks?

Answer 7

Shows water levels

Question 8

How often should a hot water boiler inspection be opened

Answer 8

5 years

Question 9

What are two options for zone control in hydronic systems?

Answer 9

Zone valves, circulator

Question 10

What valve do you find on the makeup water?

Answer 10

Globe valve and Bulb Valve.

Question 11

How do you check for water log?

Answer 11

Tap on it.

Question 12

In a hydronic boiler, what device is used to operate in high limit?

Answer 12

Aqua Stat

Question 13

How many exchange of air should there be of a prepurge?

Answer 13

4 exchange of air before pre-perge

Question 14

What is the purpose of the surface blow down valve?

Answer 14

Surface removes impurities from the water and reduces tension

Question 15

When droplets strike the system distribution pipes

Answer 15

Water hammer

Question 16

What is used for main steam stop valve

Answer 16

Gate valve

Question 17

What do you want to do with a leak?

Answer 17

Replace it

Question 18

What is the purpose of the water column

Answer 18

Reduces fluctuation

Question 19

What can cause an incomplete combustion?

Answer 19

Insufficient air

Question 20

What is the purpose of the expansion tank?

Answer 20

Allows expand and contraction in the system

Question 21

What causes priming or carryover?

Answer 21

High surface tension, high water

Question 22

What type of boiler can’t be used for high pressure?

Answer 22

Cast iron

Question 23

At what temp does thermal shock occur?

Answer 23

50 degrees between supply and return

Question 24

What is the effect of the under sized circulator on a hydronic system?

Answer 24

Poor heat delivery

Question 25

What does MAWP mean?

Answer 25

Maximum allowed weighted pressure

Question 26

The hydronic circulator size is based on what two things?

Answer 26

Gallons per min. Psig

Question 27

What factors can affect the boiler efficiency? (More than one answer)

Answer 27

Build up of scale and size of the heat exchanger

Question 28

What is the effect of an oversized circulator on a hydronic system?

Answer 28

Decrease efficiency

Question 29

What is the acceptable PH steam and hot water? (Two numbers)

Answer 29

10.5 PH
8.5 PH

Question 30

If your gauge glass is full what can it mean?

Answer 30

The top valve is plugged or closed, could be valved off, or have high water

Question 31

What can cause the relief valve to open?

Answer 31

Hot water log expansion tank

Question 32

What are the psig for steam boilers?

Answer 32

15 psig or less for steam boilers and 60 for bigger.

Question 33

What is the common setting for relief valve?

Answer 33

30 psig

Question 34

How is the capacity of the safety valve related?

Answer 34

Pounds of steam per hour

Question 35

How is the relief valve rated

Answer 35

Btu relieved

Question 36

What two devices maintain pressure in hydronic system?

Answer 36

Circulator and expansion tank

Question 37

Which boiler has fire outside the tube

Answer 37

Water tube

Question 38

What does aquastat relay control? (4 things)

Answer 38

High limit, circulator, transformer, combination blower

Question 39

Common oxygen scavenger used?

Answer 39

Sodium solfight