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Level 3 - Gas Exam 3 > Boilers Worksheet > Flashcards

Boilers Worksheet Flashcards

1
Q

What prevents the water in a hydronic heating system from boiling into steam when the system is operating above atmospheric boiling temperature?

a) natural convection
b) make up water added
c) pressurization of the system

A

c)

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2
Q

Which of the following would be considered part of a hydronic control system?

a) boiler
b) circulator
c) radiator
d) aqaustat

A

d)

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3
Q

What is installed to protect potable water connections to a boiler (make up water connections) from cross-contamination with non-potable water or toxic substances?

a) back flow preventer
b) relief valve
c) aquastat
d) low water cut off

A

a) back flow preventer

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4
Q

What is not an advantage of a hydronic heating system?

a) fast reaction time
b) quiet operation
c) increased comfort
d) less stratification

A

a) fast reaction time

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5
Q

What input would require a low water cut off for a hot water boiler?

a) 500 MBTU/h
b) 300 MBTU/h
c) 120 MBTU/h
d) 75 MBTU/h

A

a) 500 MBTU/h

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6
Q

What is used to connect multiple cast-iron boiler sections together into a boiler block assembly?

a) soldered couplings
b) threaded unions
c) tapered push-nipples
d) raised face flanges

A

c) tapered push nipples

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7
Q

What is the result if flue gas combustion products are cooled below their dew point?

a) cavitation
b) condensation
c) stratification

A

b) condensation

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8
Q

Steel water tube boilers are commonly used for the production of hot water or steam

a) true
b) false

A

a) true

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9
Q

To prevent thermal stress damage, this type of boiler requires constant water circulation

a) steel fire tube
b) cast-iron sectional
c) copper fin-tube
d) steel water-tube

A

c)

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10
Q

Condensing boilers are typically made fro what material?

a) cast iron
b) stainless steel
c) copper

A

b)

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11
Q

For atmospheric boilers, what is the term used to explain the result if there is no draft, a backdraft, or a blockage in the venting system beyond the draft hood?

a) leakage
b) spillage
c) discharge

A

b)

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12
Q

What does an automatic vent damper actuator have to control the boilers burner?

a) proving switch
b) igniter
c) transformer

A

a)

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13
Q

What is the simplest type of hydronic system?

a) reverse return
b) direct-return
c) series loop
d) monoflo

A

c)

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14
Q

Which two-pipe system is easiest to balance?

a) reverse-return
b) direct-return
c) series loop

A

a)

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15
Q

Which hydronic distribution system uses diverter valve tees to help direct main water flow through the heating unit?

a) reverse return
b) direct return
c) series loop
d) monoflo

A

d)

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16
Q

Which hydronic distribution system is known as “first-fed, first-return”?

a) reverse return
b) direct return
c) series loop
d) monoflo

A

b)

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17
Q

What device within a closed hydronic system accommodates for the volumetric change of the system fluid under normal operating conditions?

a) expansion tank
b) relief valve
c) air separator
d) high limit aqua stat

A

a)

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18
Q

Which device within a hydronic heating system is require to release water during an unsafe condition caused by excessive pressures?

a) expansion tank
b) relief valve
c) air separator
d) high limit aqua stat

A

b)

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19
Q

Which type of valve is best suited for throttling flow?

a) gate valve
b) globe valve
c) check valve
d) relief valve

A

b)

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20
Q

A thermostatic radiator valve can be operated by mechanical or electric drive head?

a) true
b) false

A

a)

21
Q

What side of a structure should an outdoor thermostat sensor be placed?

a) north
b) south
c) east
d) west

A

a)

22
Q

What is the purpose of a balancing valve?

a) increased flow
b) isolate flow
c) equalize flow
d) stop reverse flow

A

c)

23
Q

What is installed in a system to ensure continuous flow in the system, no matter how many one valves are open or closed?

a) four-way mixing point
b) differential pressure bypass
c) outdoor air sensor

A

b)

24
Q

This device is normally wired in series with an operating aqauatsat so that either one can shut off the burner?

a) bypass limit
b) high limit
c) low limit
d) no limit

A

b)

25
Q

What can be used to sense problems in the flow of combustion products (ike flue blockages)

a) rollout switch
b) flow switch
c) low water switch
d) proving switch

A

a) rollout switch

26
Q

What valve is used to prevent reverse flow in a piping system?

a) gate valve
b) globe valve
c) check valve
d) relief valve

A

c) check valve

27
Q

What can be used to provide “hydraulic separation” in a primary/secondary hydronic distribution system?

a) monoflo tees
b) closely-spaced tees
c) diversion tees
d) oversized tees

A

b)

28
Q

The pressure difference a pump can produce between its inlet and outlet ports isn definition of which of the following?

a) flow rate
b) velocity
c) head
d) drift

A

c)

29
Q

Ho9w many US gallons would be required to supply 40,000btu/h if the design temperature drop for the system is 30F (-1C)

a) 3.75
b) 2.67 us gpm
c) 5 us gpm

A

b) 40,000/30 x 500

30
Q

What is the effect of installing two centrifugal pumps in series?

a) 50% more pressure
b) half the flow
c) double the flow
d) double the pressure

A

d)

31
Q

What is the effect when a shutoff valve is closed downstream of a centrifugal circulator?

a) current draw decreases
b) current draw increases
c) voltage increases
d) voltages decreases

A

a)

32
Q

What is the name for the point where the expansion tank is attached to the system piping?

a) point of no point
b) point of view
c) point of no pressure change
d) point of no return

A

c)

33
Q

Immediately upstream of the expansion tank is the best place to install a primary circulating pump in a hydronic system?

a) true
b) false

A

b)

34
Q

What is the rotating piece of a centrifugal pump called?

a) impeller
b) propeller
c) volute

A

a)

35
Q

What is the effect when increasing the rpm of a centrifugal pump?

a) more pressure and more flow
b) less flow
c) more flow
d) more pressure

A

a)

36
Q

Where is the area of lowest pressure within a centrifugal circulator?

a) impeller eye
b) volute
c) outlet port
d) pump buddy

A

a)

37
Q

What is the typical system design pressure for a residential hydronic boiler?

a) 50-60 psig
b) 20-28 psig
c) 12-15 psig
d) 32-45 psig

A

c)

38
Q

What should be checked first if the boiler system pressure is higher than normal?

a) expansion tank
b) relief valve
c) low water cut off
d) PRV

A

d)

39
Q

How can a technician increase a hydronic systems static pressure setting?

a) turn the PRV adjustment clockwise
b) turn the PRV adjustment counter-clockwise
c) open the relief valve
d) open the boiler drain

A

a)

40
Q

You tell if a differential pressure bypass valve is working correctly if the pressure at the discharge side of the pump does not increase when zone valve close

a) true
b) false

A

a)

41
Q

If a boilers burner will not fire, which of the following should be check first?

a) aquatsats
b) water supply
c) venting system
d) air vents

A

a)

42
Q

What is the likely cause of incomplete combustion and high flue stack temperatures?

a) air in the system
b) low water condition
c) over-firing the burner

A

c)

43
Q

Air in the system can create what common problem?

a) noise
b) high velocities
c) condensation

A

a)

44
Q

Who can test a back flow preventer?

a) certified tester
b) gas technician
c) homeowner
d) plumber

A

a)

45
Q

If the pressure in a hydronic system increases immediately after the burner comes on, what is the cause?

a) expansion tank is water-logged
b) relief valve is faulty
c) prv is faulty
d) gas pressure is too low

A

a)

46
Q

What happens if a zone valves end switch fails to close?

a) thermostat will open
b) pump will not shut off
c) burner will not fire
d) PRV will open

A

c)

47
Q

A customer complains there is no heat in the top floor of a hydronic heating system. What is the most likely cause?

a) zone valve is stuck open
b) air lock in system
c) pump is oversized

A

a)

48
Q

What should be observed to avoid pump cavitation?

a) install straight piping system
b) keep fluid temperature as low as possible
c) keep static pressure as high as possible
d) all of the above

A

d)

49
Q

What is the maximum setting for a pool boilers high limit aqua stat?

a) 100F
b) 140F
c) 160F
d) 180 F

A

b)

Level 3 - Gas Exam 3 (4 decks)

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