Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Danica’s Steamfitter III Review > Hydronic Heating and Cooling Systems, Trim and Piping > Flashcards

Hydronic Heating and Cooling Systems, Trim and Piping Flashcards

1
Q

Hydronic heating systems can be divided into two categories based on how the water is delivered to the system. What are these two categories?
A. Circulated and returned
B. Gravity, and forced.
C. Pumped and vacuumed.

A

B. Gravity and forced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the difference between a forced system and a gravity system?

A

A gravity system uses the thermal convection current of the water to circulate in the system, and a force system uses circulation pumps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is another name for a mono flow tee?

A

Venturi tee

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Some advantages of a one pipe system is that it has less piping than a two pipe system, each heat transfer unit can be individually controlled and both up feed and down feed systems are supplied evenly. What are the disadvantages of a one pipe system?

A

The size of the piping is limited to the available sizes of the Venturi tees, branch lengths have to be limited in order to reduce friction, heat transfer units with high resistance don’t work well with this system, and similar to the series system, the temperature of the water decreases after each heat transfer unit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is another name for a series loop system?

A

Perimeter loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

A Disadvantage of the series loop system is that due to having no return from each heating unit, the first convector receives the hottest water while the last unit receives the coolest water. In addition, temperature control is limited because the entire circuit can only be controlled by one device. what are some advantages of the system?

A

The major advantage of the series system is the reduction in the amount of piping required. Therefore saving installation costs, as there is no separate supply and return piping.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two types of two pipes systems?

A

Reverse return, and direct return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True or false? I major advantage to the two pipe direct return system is that due to the unequal length of circuits, the system is naturally balanced, and no valves are required?

A

False. Having unequal length of circuit is a major disadvantage as this Makes the system prone to short circuits, and this is fixed by installing balancing valvesa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

True or false? A reverse return piping system returns condensate from the furthest heating unit back to the boiler first?

A

False. In a reverse return system, The first boiler to receive a supply is the last boiler to feed the return.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which hydronic heating system is the preferred piping method for majority of installations?

A

Reverse return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the advantages and disadvantages of a reverse return system?

A

The advantages are that the system is easy to balance. And individual units can be controlled. Disadvantage is that it has much more piping than a series and one pipe system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the purpose of a wild loop?

A

To prevent the circulation pump from deadheading

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the name of the piping system in which the heat transfer units are part of the piping?

A

Series loop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the name of the piping system which the heat transfer units are supplied by specialty tees?

A

One pipe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the name of the piping system in which the water has approximately the same distance to travel for each heat transfer unit?

A

Two pipe reverse return

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a major disadvantage of the series loop piping system?

A

Limited heating capacity for each circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the major disadvantage of a one pipe system?

A

End heat transfer units receive cooler water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the major disadvantage of a 2 pipe direct return piping system?

A

Hard to balance flow to each transfer unit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following valves is a good choice to use as an isolation valve?
A ball valve.
B. needle valve
C. globe valve
D. check valve.

A

A. Ball valve.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the purpose of balancing valve?

A

To adjust flow rates to each transfer unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the purpose of a zone valve?

A

To provide control of heat emissions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the two primary considerations when locating air removal devices?

A

Temperature and pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why is it important to remove gases from a hot water heating system?
A. to prevent convection from occurring.
B. to prevent air binding in the system.
C. period to prevent over pressuring of the system due to expansion

A

B. to prevent air binding in the system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What device removes gases directly from the boiler?

A

Boiler scoop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where should you locate air vents in the system?

A

At all high points.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What part of a circulator transfers energy to the water

A

The impeller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What function does a circulator provide in a hot water heating system?

A

Moves the water within the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Where is the best location for a circulator?

A

Downstream from the compression tank

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the purpose of a flow control valve?

A

To prevent convection currents in a heating system

30
Q

What is the primary purpose of a heating system?

A

To provide comfort to the individuals in the space

31
Q

What is the greatest advantage of hydronic heating over any other system?

A

Multiple zoning

32
Q

What is a heated area that is regulated by one circulator, control or thermostat Called?

A

A zone

33
Q

What is the name of the pump used mainly on hydronic heating systems?
A. Centrifugal
B. positive displacement.
C. High head low displacement

A

centrifugal.

34
Q

What is the purpose of a 4 way mixing valve in the boiler system?

A

To ensure a constant flow of tempered water through the boiler

35
Q

When a 4 way valve is used, the flow rate through the boiler remains constant, true or false.?

A

True

36
Q

True or false? a reset control measures outdoor temperature and calculates a supply temperature.

A

True

37
Q

True or false? Electronic feedback controls use liquid filled sensing bulbs and capillary tubes as outdoor sensors.

A

False.

38
Q

What is the function of a low water cut off on a low temperature hot water boiler?

A

To shut off burners in a low water situation

39
Q

What should be installed to prevent short circuiting in a two-pipe hydronic system?

A

A balancing valve.

40
Q

What is the difference between a direct return and reverse return two pipe hydronic system?

A

A direct return is first supplied, first returned and a reverse return is a first supplied last returned.

41
Q

Dual temperature system heat transfer units are sized in accordance with___________________.

A

Cooling load

42
Q

Why are zone valves installed in a hydronic system?

A

To stop and start flow in the system as required

43
Q

What provisions must be made when a hydronic heating system is installed in a building?
a. Forced air system for supplemental heat.
b. windows to reduce heat transfer.
C. a means of exchanging air within the building.

A

C. A means of exchanging air within the building.

44
Q

What is the purpose of the three pipe system?

A

To temper the air at the reheat boxes in the condition space. They are designed to provide a constant supply of either hot or chilled water to the mixing valve at the heat transfer unit.

45
Q

When would a 4 pipe system be used.

A

When there are different heating and cooling requirements for different rooms or zones.

46
Q

What are the two basic principles of pumps?

A

Transfer and circulation

47
Q

What are the two factors you need to know in order to determine the right size pump for the application?

A

Flow rate and pressure loss.

48
Q

What is pressure loss?

A

The resistance of flow caused by the medium traveling within the piping system.

49
Q

What is head pressure

A

The pressure available at the outlet of the pump expressed in feet of head.

50
Q

True or false? piping must be connected solidly to pumps so they move together.

A

False.

51
Q

What is the cause of cavitation?

A

Oversized pump for application causes pressure drop at the eye of the impeller. and air or gases entrained in the medium.

52
Q

What is the maximum operating temperature and pressure of a low temperature hot water boiler?

A

120 degrees Celsius and 160PSI. cast iron is 30 PSI.

53
Q

How are low-temperature boilers usually rated?

A

Net rated and btu per hour or EDR.

54
Q

Which of the following is a definition of net rating??
a. Amount of heat energy available at the heat transfer unit.
B. The amount of heat energy consumed by the boiler.
C. Amount of heat energy available at the boiler outlet.

A

A. amount of heat energy available at the heat transfer unit.

55
Q

The amount of energy consumed by the boiler is The definition of what?

A

Boiler input

56
Q

What problems can occur in a conventional boiler if the flue gases are cooled to their Dew point?

A

Draft Hoods Spillage or damage caused by corrosive condensate.

57
Q

Does a cast iron sectional boiler classified as a low mass or high mass boiler?

A

High Mass,

58
Q

Which code covers the fabrication, installation and inspection of boilers?

a. ASTM code
B. ASME code.
C. CSA code.

A

ASME code.

59
Q

Is a fire tube boiler classified as a high mass or a low mass boiler?

A

High mass

60
Q

What can cause coil damage in a low mass boiler?

A

Low or no flow through the heat exchanger.

61
Q

What material are sectional boilers typically constructed out of?

A

Cast iron.

62
Q

What is the purpose of a safety relief valve?

A

To protect the boiler and system from excess pressure

63
Q

What is the purpose of a boiler operating control?

A

To control the normal temperature range of a boiler.

64
Q

What device protects the boiler from excessive temperature?

A

Limit Control.

65
Q

What mandatory device is required on a coil-type boiler over 400,000 BTU per hour.

A

Flow switch

66
Q

What device can be installed to protect a hot water boiler from a low water level?
A. limit control
B . flow switch.
c. Probe type cutoff.

A

Probe type cut off.

67
Q

What device compensates for the normal expansion and contraction of the water in a hot water boiler?

A

Diaphragm tank

68
Q

What device separates air from the water, leaving the boiler??

A

Boiler scoop

69
Q

What device is used to maintain a minimum pressure within a system?
a. Safety relief valve.
B. pressure reducing valve
C. operating control.

A

Pressure reducing valve.

70
Q
A

Danica’s Steamfitter III Review (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions