Brainscape's Knowledge GenomeTM

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


See full index

Plumbing Level 3 > F2: Radient Systems > Flashcards

F2: Radient Systems Flashcards

1
Q

What type of Pex was created using the Engel method and has a memory?

A

PeX A

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

What kind of fittings can PeX A be used with?

A

expansion type, crimp / compression

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

What is PeX A’s best quality?

A

ability to be kinked / repaired by just adding heat

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

Can PeX B and C use expansion fittings?

A

No and any kinks have to be cut out / replaced.

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

What kind of Pex has to be used when installing radiant panels?

A

The type that has an oxygen barrier coating for heating.

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

What does the oxygen barrier provide?

A

minimizes the rate of oxygen diffusion (decreases rusting
This type of pipe is red in colour

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

True or False: adding rust inhibitors additives to radiant system helps keep level of free oxygen low

A

True

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

What is a Wet system?

A

PeX tubing is embedded within a concrete mass

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

Is a wet system the best option for a radiant heat transfer in a house?

A

Yes

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

What does WWF stand for?

A

Wire mesh

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

What does the spacing between ties have to be to ensure the tube doesn’t float up in the concrete slurry?

A

24” between ties

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

Should you use an open flame to fix kinked PeX A tubing?

A

No

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

Can joints be used in embedded concrete?

A

No
AHJ will not allow it

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

What is the min of rigid polystyrene foam used between the vapour barrier and the slab bottom?

A

2 1/2”

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

True or False: most installers only use foam for the first 2 feet from the outer wall.

A

True - one the ground settles heat loss is min

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

What is the most common way to install in floor heating?

A

using 1 1/2” thick concrete / gypsum mixture (poured in two “lifts” over 1/2” tubing) and tubing is stapled to the plywood subfloor.

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

What’s the less common way of installing in floor heating?

A

using pre-formed plastic mats

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

What type of system is used outdoors as a snow melt system?

A

A wet system

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

What kind of circulating solution is used for outdoor systems?

A

Antifreeze or brine

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

How is the outdoor system separated from the building heating system?

A

through the use of a heat exchanger

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

The heat exchanger acts as what?

A

as a boiler –> would need it’s own expansion tank, circulator and make up water (and backflow preventer)

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

What is a “Dry System”?

A

In floor heating system used indoors

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

Where is the most common spot for a dry system to be installed?

A

Joist space - min 2 pex runs are attached to the sides of the joist placed 3” below the subfloor

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

What is the less common way of installing a dry system in the joists?

A

using hangers to support pipe

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

What is a major down-side of installing in floor between joists?

A

Air being trapped in the joist space

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

Is air a better insulator or a conductor?

A

A better insulator

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

What is an even better way to run in floor heating?

A

Using aluminum plates that are stapled to the underside of the floor.
This has a better heat transfer rate.

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

Are dry system temperatures higher or lower than wet systems?

A

Much higher

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

Does insulation have to be installed between joists if in floor heating is installed?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

True or False: The insulation between joists has to have a higher R value than subfloor/ floor covering.

A

True, the heat will be driven upwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What kind of radiant panel is used in institutions? (hospitals / schools)

A

Radiant ceiling panels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What type of in floor heating layout is the most common for 1 - 2 outside walls?

A

S-shaped serpentine pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What type of in floor heating layout is most common for multiple outside walls?

A

Spiral (counter flow) pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the main consideration in loop layouts?

A

That the warmest water should always be delivered to the area of greatest heat loss first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How is tube spacing determined?

A

tube size and the floor output in BTUH/ft2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the most common spacing in residential?

A

12” - 9” - 6” (4” is less common but usable)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What would happen if the heat output exceeds 40 BTUH/ft2?

A

the high temp would be uncomfortable and supplemental heat (baseboard wall fin) has to be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how is the max length of radiant tubing determined?

A

on the loops delta T and size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What happens if the recommended tube lengths are exceeded?

A

frictional resistance increases –> causes more pressure on circulator / water flow rate is less than expected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

A total heat loss estimate will tell us what?

A

each room’s heat loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Where shouldn’t tubing be installed and why?

A

Under cabniets - ineffective
Kitchen - ineffective/ food spoils quickly
Under stoves/ refrigerator- both generate heat
Toilet bowl - melts wax ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Who has to approve joint or connection in concrete?

A

Manufacturer or AHJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

How much concrete should be maintained over tubing?

A

3/4”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the max spacing between ties on a straight run?

A

3m (10’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the max spacing between ties on bends?

A

0.2m (8”)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the heat plant most commonly associated w/ Hydronic heating?

A

Boilers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the determining factor when sizing heat loss?

A

The heat plants OUTPUT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

If the boiler’s output is greater than the heat load, this ensures what?

A

That there is enough of a buffer to deliver the heat needed even of the coldest days of the year.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What does the choice of piping dictate when sizing a circulator?

A

How many circulators are needed
Where they are to be located

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Where should pumps be installed?

A

Downstream of the “point of no pressure change”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the point of no pressure change?

A

The point in the piping system where the expansion tank attaches to the supply main

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the pumps job?

A

To move water when zones call for heat
produce pressure needed to overcome frictional losses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Head loss that a pump has to overcome, comes from where?

A

It only has to overcome the single circuit w/ the most frictional resistance which includes head loss through the longest loop that it supplies.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How is Circuit length measured?

A

Start from pumps outlet –> most remote manifold or heat emitter / back to the pump’s inlet
Add 50% - accounts for extra frictional resistance caused by fittings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

True or False: Having multiple small, high head, low flow rate pumps is that way to go with todays hydronic systems.

A

True

57
Q

How are pumps picked?

A

Flow rate required (USGPM)
Resistance to flow that the pump must overcome (in feet of head)

58
Q

How are flow rate (GPM) and resistance to flow (head) calculated?

A

Through pump curve

59
Q

How is high head described?

A

High pressure, Low flow

60
Q

How would Low Head be discribed?

A

High flow, Low pressure

61
Q

What are key points to remember when selecting a pump?

A

1) Choose the pump with the flattest curve –> avoiding excessive pressures = noise
2) Pump curve has to be above the max requirements when plotted => overcoming head loss/ still move water
3) use middle third of graph = most effective

62
Q

True or False: the height of a closed system has no effect on a pump’s operation.

A

True

63
Q

The pump only has to overcome what?

A

Frictional resistance

64
Q

What language does a pump speak?

A

GPM

65
Q

Frictional losses will increase if the what increases?

A

The flow rate

66
Q

Hot water systems want what kind of flow rates?

A

Low (1-4 feet/sec)

67
Q

What happens if water moves too quickly through the system?

A
  • There would be an increase noise / erosion
  • Less time for heat to be heated up
68
Q

In domestic potable water systems, How is friction loss expressed?

A

PSI / foot
feet of head/foot

69
Q

In hydronic heating systems, how is frictional resistance expressed?

A

millinches / foot

70
Q

What is the designers norm for frictional losses?

A

400 millinches / foot

71
Q

1 psi = how many feet of head?

A

2.31

72
Q

1 foot of head = how many psi?

A

.433

73
Q

Who supplies head losses for various types / sizes of tube at diff flow rates / temps / different glycol mixtures?

A

Manufactures

74
Q

What temp of water has more frictional resistance?

A

cold water

75
Q

True or False: When using glycol in in floor heating systems a backflow preventer is needed

A

True

76
Q

Where would a backflow preventer be installed?

A

On the cold water makeup to the system

77
Q

What is the normal backflow preventer to use on a residential system?

A

Dual check w/ atmospheric port (DCAP)

78
Q

What is the most common type of Glycol

A

Polypropylene glycol

79
Q

Why is Polypropylene glycol popular?

A

Known as the food grade antifreeze.
non- toxic but expensive

80
Q

What type of glycol is popular in the automotive industry?

A

Ethylene glycol
(extremely toxic)

81
Q

Does glycol have an effect on pumps and expansion tanks?

A

Yes

82
Q

a 50% glycol / water mixture will make water how much harder to move? (% wise)

A

14 - 22%
in turn also creates more head pressure

83
Q

What does glycol have a detrimental effect on?

A

Rubber –> the rubber ball inside a zone valve.

84
Q

Why are balancing valves used?

A

To create an accurate flow rate through a circuit

85
Q

What type of valve is a balancing valve?

A

low - loss type of globe valve

86
Q

Balancing valves will also have what type of plug on them?

A

Pete’s plugs –> on the upstream / downstream side of the valve seat

87
Q

When does water have to be tempered?

A

When a system requires water temps that differ greatly

88
Q

How many ports does a mixing valve have?

A

2 - 4

89
Q

Where are mixing valve located?

A

at the Mixing point : where high temp and low temp water merge

90
Q

What is a thermostatic mixing valve?

A

a valve that is manually set to supply a constant temp

91
Q

What is a Reset control mixing valve?

A

a motorized actuator / controller that is capable of modulating temps as thermal conditions change

92
Q

what type of valve has the same entering / leaving temps and is located on the return piping?

A

Diverting valves

93
Q

What is Injection Mixing?

A

It’s when a pump is used to ‘inject’ an amount of hot water into the supply side of a manifold

94
Q

What type of system commonly uses Injection mixing?

A

Primary - Secondary piping systems

95
Q

What does a variable - speed pump do?

A

sets itself to the speed required in order to maintain a desired temp

96
Q

Why must multiple pumps that share pipe be hydraulically separated?

A

So that the operation of one pump does not affect the operation of the other

97
Q

How is hydraulically separation achieved?

A

by using a hydraulic separator
or
tees located very close to one another

98
Q

Do pumps have to work harder or easier to pump water through brazed plate heat exchangers?

A

Harder

99
Q

What is a CV value?

A

it is the flow rate in GPM through the valve that would result in a 1 psi pressure drop across it

100
Q

What is the System Operating Point?

A

The intersecting lines on a pump graph that indicate the max needs of the system in head loss / flow rate

101
Q

What has to happen for a pump to be effective?

A

the pump curve has to fall above the system operating point

102
Q

What happens if the pump curve falls below the system operating point?

A

pump won’t put out enough pressure at the required flow rate to offset frictional losses

103
Q

a noisy system is due to?

A

excessive pressures

104
Q

Where on the pump curve is the circ’s efficiency high?

A

within the middle third of their pump curve.

105
Q

An expansion tank is located where to a circ pump?

A

as near to the inlet side of the circ as possible

106
Q

Why is a differential pressure valve installed on systems using a single pump / multiple zone valves?

A

to avoid over - pressurizing the system

107
Q

What will a differential pressure valve (DPV) do when excessive pressure is sensed?

A

It will open to bypass water from the supply main to the return main

108
Q

What kind of circulator is used on larger hydronic systems?

A

Variable - speed circulators
(regulates differential pressure)

109
Q

What are Electronically commutated motors (ECM) ideal for?

A

systems using valve-based zoning
(eliminates need for differential pressure bypass valve)

110
Q

What happens to pressure output when two pumps are in a series?

A

Pressure output doubles
Flow rate = remains unchanged

111
Q

What happens the there are two circulators in parallel?

A

Flow rate = doubles
Output pressure = stays the same

112
Q

What job does an expansion tank have?

A

Keeps the system pressure from fluctuating widely when system heats up and cools off

113
Q

What other names are given to an Expansion tank?

A

Cushion tank
Compression tank

114
Q

What happens if there was no expansion tank?

A
  • pressure builds up, trips pressure relief valve -> discharges system water to max level.
  • When boiler shuts off / water cools –> pressure drops below fill valve’s set point
    water is added to desired set point.
    This continuously happens when boiler turns on / off
115
Q

What happens with the constant addition of water to a boiler?

A

rust

116
Q

To correctly size an expansion tank, what must we know?

A

1) min / max operating pressures
2) system vol in gallons
3) min / max operating temp
4) Glycol % mixture (if used)

117
Q

A properly sized expansion tank should have a max pressure of?

A

5 psi lower than the relief valve setting (prevents relief valve from leaking)

118
Q

Should the pressure on the air-side of the diaphragm be adjusted before or after adding fluid?

A

Before

119
Q

What happens if a tank is underpressurized?

A

it can cause the relief valve to open each time the system heats up

120
Q

True or False: Glycol has an effect on the rate of expansion depending on the % of glycol in the system.

A

True

121
Q

What are the 2 locations where there’s a choice of pipe size?

A

Radiant tubing - on either a wet or dry system
Piping in the mains / branches bn boiler / manifold.

122
Q

In a primary / secondary system, boiler / primary loops are sized according to what?

A

Output of the boile

123
Q

piping in secondary loops are sized according to what?

A

Heat load of that particular loop

124
Q

What is the temperature differential between the supply and return radiant flooring?

A

20F

125
Q

What is the max length of a 1/2” loop using a temp diff of 20F?

A

300’

126
Q

What kind of spacing is 1:1?

A

12” (12/12 = 1)

127
Q

What kind of spacing is 1.3:1

A

9” (12/9 = 1.3)

128
Q

What kind of spacing is 2:1

A

6” (12/6 =2)

129
Q

What kind of spacing is 3:1

A

4” (12/4 = 3)

130
Q

a 20F temp differential produces how many GPM?

A

10,000

131
Q

A 15F temp differential produces how many GPM?

A

7500

132
Q

A 10F temp differential produces how many GPM?

A

5000

133
Q

Once concrete is finished pouring, what should be done with the water pressure in the pipe?

A

Water pressure can be released from tubing (blow out with dry air - prevents freezing)

134
Q

Until concrete is at max pressure what shouldn’t be done?

A

Do not re-pressurize tubing

135
Q

True or False: The pump that has the flattest curve should be chosen

A

True

136
Q

True or False: The height of a closed system has no effect on a pump’s operation

A

True

137
Q

How do heat exchangers have enormous heat exchanging capacities?

A

The stainless steel plates inside have a huge surface area

138
Q

What is waterlogged?

A

When air is reabsorbed into the water –> this reduces air vol until tank has little air

Plumbing Level 3 (26 decks)

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