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Lvl. 4 Gas - Exam #3 Final > K3.3-3.5/Notes > Flashcards

K3.3-3.5/Notes Flashcards

1
Q

Why do we purge?

A
  1. Safely introduced gas/fluid (gasifying)
  2. Safely remove gas/fluid to repair/abondon
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2
Q

Flaring is the controlled burning of natural gas through a flare stack. True or False?

A

True

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3
Q

U-tube manometer is also known as a ?

A

slack tube

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4
Q

Must measure the bottom of the meniscus on a slack tube/u-tube manometer. True or False?

A

True

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5
Q

What is the purpose of a combustion analysis?

A

ensure safety and efficiency

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6
Q

If a desiccant filter is brown it should be?

A

replaced

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7
Q

Where to measure for a combustion analysis?

A

At the breach before the draft hood

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8
Q

Can excess air be adjusted on a natural draft appliance?

A

NO

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9
Q

Can excess air be adjusted on a forced/induced/fan assist appliance?

A

Yes

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10
Q

Excess air greatly lowers the formation of CO by allowing CO to react with O2. True or False?

A

True

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11
Q

What is NOX?

A

Nitrogen pollutants generated by boilers (NO and NO2)

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12
Q

Why don’t we like NOX?

A

Results in production of ozone and acid rain

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13
Q

How is NOX formed? (two types)

A

Thermal NOX: nitrogen and oxygen react in flame

Fuel NOX: nitrogen and oxygen react in comb air

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14
Q

Two ways to control NOX?

A
  1. Post combustion
  2. Combustion control
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15
Q

What is the most expensive way to control NOX?

A

Post combustion control

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16
Q

Post combustion control techniques are generally not used on boilers smaller than 1000MBH. True or False

A

True

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17
Q

What is a post combustion control technique to mitigate NOX?

A

Selective and non-selective catalytic reduction

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18
Q

What is a combustion control technique to mitigate NOX?

A

Burner mods, flue re-circulation, water/steam injection

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19
Q

Installer shall instruct user in safe operation of appliance they install. True or False?

A

True

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20
Q

Installer shall ensure manufacturer instructions supplied with appliance are left with the user. True or False?

A

True

21
Q

Net flue temperature?

A

difference between stack temperature and ambient temperature

22
Q

The owner must be trained in safe start-up and operation of appliance. True or False?

A

True

23
Q

Flue vent dew point is in what range?

A

120-150F

24
Q

Causes of flue vent condensation? (4)

A
  1. over-sized venting
  2. low flue temps
  3. venting in cold area
  4. under-firing
25
Q

Flue venting shall be sloped _______ the appliance at __” per foot

A

towards

1/4”

26
Q

Pressure vessels are usually tested to ___MOWP

A

1.5mowp

27
Q

What is refractory?

A

heat resistant material that lines high temperature areas

28
Q

Mixing valves are usually preset to?

A

130F

29
Q

Expansion tanks are typically pre-charged to?

A

12-15psig

30
Q

For many stories, pressure must be added the expansion tank. True or False?

A

True

31
Q

For expansion tanks, how many psig/ft must be calculated?

A

.433psig per ft

Example: 15psig / .433 = 34.64ft of head

32
Q

Steam control zone valves work on the same principle as hydronic zone valves. The main difference is the?

A

valve body

33
Q

Main purpose of steam traps?

A

allows steam to escape and keep the steam/water separate

34
Q

Thermodynamic steam traps are only used in _____ pressure systems

A

high pressure systems

35
Q

Common cause of steam trap failure?

A

dirt/scale not allowing valve to close

36
Q

Good HSI has resistance of ___ to _____ ohms

A

30-200ohms

37
Q

HSI resistance readings will be higher when the HSI is _______

A

warmer

38
Q

Silicone nitride HSI are more reliable and last longer than silicone carbide HSI. True or False?

A

True

39
Q

Replace HSI when resistance reads round?

A

70-90 Ohms

40
Q

Typically furnace modulating percentage?

A

40-100% CAPACITY

41
Q

What is the recommended gap size to ground for a spark igniter (ignition electrode)

A

1/8”

42
Q

Which type of flame safeguard operates on flame rectification?

A

flame rod sensor

43
Q

A good ______ is necessary to rectify a circuit

A

ground

44
Q

Minimum flame rod ratio to ground is __:1 although 10:1 is recommended

A

4:1

45
Q

What can happen if the flame rod touches ground/refractory?

A

changes the DC signal to AC

46
Q

Flame rod sensor shall have no continuity from the sensor wire to ground. True or False?

A

True

47
Q

Most controls will drop out of the flame rod sensor reads around __micro amps DC or less

A

2

48
Q

During pilot operation the flame rod must read steady __micro amp DC

A

1

49
Q

A smaller K factor passes less gas. True or False?

A

True

Lvl. 4 Gas - Exam #3 Final (6 decks)

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