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Course L > Gas - Unit N > Flashcards

Gas - Unit N Flashcards

1
Q

List two ways of heating domestic hot water.

A

Instantaneously, as water is needed.

Storage tank, at a constant tempurature.

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2
Q

What is the normal tempurature of domestic hot water?

A

140°F.

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3
Q

True or False?

Forced-air central furnaces can only blow air in an upward direction into the duct work?

A

False.

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4
Q

List two types of furnaces which could use duct work in a crawl space.

A

Down-flow.

Horizontal-flow.

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5
Q

What would constitute a high pressure hot water boiler system?

A

Over 30 psig.

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6
Q

List three categories of commercial gas ranges.

A

Heavy duty.

Oriental[][][][]

Restaurant[]]

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7
Q

List two types of infrared heaters.

A

Low intensity.

High intensity.

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8
Q

What surace tempurature can be reached on a high-intensity heater?

A

1800°F.

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9
Q

List six items you should check before installing a gas appliance.

A

Accessibility of appliance.

Electrical supply (current voltage).

Gas supply (correct pressure)[][][][]

Permit (gas, electrical, plumbing)[]]

Suitability of location[][][][][][][][][][][][][]

Water supply and drainage[][][][][][][]]

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10
Q

List five major items you would check after installing a gas-fired appliance.

A

Air supply for combustion.

Electrical wiring[][][][][][][][][][]

Flues and vents[][][][][][][][][][]

Gas piping[][][][][][][][][][][][][][][]

Water and drainage[][][][][][][]

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11
Q

Is it the general contractor’s responsibility to ensure there is combustion air supply?

A

No, it is the gasfitters responsibility.

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12
Q

What are the two main things you must do before you light up an appliance?

A

Purge the piping system of air.

Test for gas leaks[][][][][][][][][][][][]

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13
Q

True or False?

After turning on the main gas valve for the first time, you should immediately head for the appliance and check for leaks.

A

False (first make sure gas flow stops).

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14
Q

How long must the house pressure be locked in, with no pressure drop showing on the manometer of the pressure guage?

A

10 minutes.

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15
Q

Natural gas is used to purge a system of air when the pipe size is less than NPS _.

A

4.

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16
Q

List three locations where air can be purged from a small piping system.

A

Appliance piping connection.

Pilot tube connection to gas valve.

Readily accessible burner[][][][][][][][]

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17
Q

True or False?

It is okay to allow some gas into the combustion chamber while purging?

A

False.

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18
Q

How far must the end of the purging hose be from either a building opening or an air intake?

A

10 feet.

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19
Q

What type of valve must be used at the purging point?

A

Quarter-turn.

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20
Q

Name the device installed on a domestic hot water tank that will prevent siphoning.

A

Vacuum relief valve.

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21
Q

Name the device that will protect the hot water tank from high tempuratures and pressures.

A

Tempurature and pressure relief valve.

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22
Q

If the tempurature selector knob on a domestic hot water tank is turned to the normal setting, what tempurature should the water be heated to?

A

140°F.

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23
Q

Switch that immediately closes the safety shut off valve when set tempurature exceeded is the definition of?

A

Energy cut off.

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24
Q

What is the pressure relief setting for a low pressure hot water boiler?

A

30 psig.

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25
Q

What is the maximum operating pressure for a low pressure steam boiler?

A

15 psig.

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26
Q

What must be checked on a circulating pump before it can be put into service?

A

Lubrication.

Rotation[][][]

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27
Q

What is the normal tempurature for an operating aquastat (on a hot water boiler)?

A

180°F.

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28
Q

What is the normal tempurature for a high-limit aquastat?

A

200°F.

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29
Q

What are the pressure ranges of an operating pressuretrol (in a low pressure steam boiler)?

A

On at 1 pisg, Off at 3 psig.

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30
Q

What is the normal high-limit temperature setting for a forced warm-air furnace?

A

200°F.

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31
Q

Describe the setting on a fan/limit combination control on a forced warm-air furnace.

A

Fan on 20° above fan off setting Fan off 20° above thermostat setting.

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32
Q

Desrcribe how you can test the operation of a high-limit switch in a forced warm-air furnace.

A

Disconnect fan motor or fan belt to create high tempurature; ensure high-limit de-energizes gas valve.

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33
Q

What is the clearance requirement of a moisture exhaust duct that is connected to a domestic cloths dryer?

A

None.

34
Q

What is the clearance requirement of a moisture exhaust duct that is connected to a commercial cloths dryer?

A

6 inches.

35
Q

What is the high-limit setting on a commercial cloths dryer’s high-limit switch?

A

200°F.

36
Q

Suggest two reasons why a flame might burn on the top side of the ceramic panels on an infrared heater.

A

(Cracks and leaks)

Check cermic matrix for cracks.

Check gaskets between ceramic panels for leaks.

37
Q

After connecting the gas meter and appliances to the piping system and determining there are no gas leaks, each appliance connection, valve, valve train and system component shall be checked while under normal operating pressure with:

A. A manometer connected to the manifold

B. A pressure guage[][][][][][][][][][][][][][][][][][][][][]]

C. Your nose[][][][][][][][][][][][][][][][][][][][][][][][][][][][][]

D. A liquid solution[][][][][][][][][][][][][][][][][][][][][][][]]

A

D. A liquid solution.

38
Q

To meet Code requirements, purging the natural gas from a small domestic system can be performed by:

A. Carefully loosening the union at the appliance.

B. Attaching a purge hose to the manifold piping.

C. Disconnecting the pilot tubing from the gas valve.

D. Purging through the pilot burner[][][][][][][][][][][][][][][][][]

A

C. Disconnecting the pilot tubing from the gas valve.

39
Q

Every water heater shall have a tempurature and pressure relief device on which the discharge pipe shall terminate not more than:

A. 1 pipe diameter above a floor drain.

B. 2 pipe diameters above a floor drain.

C. 12 inches above the floor[][][][][][][][][][][]

D. 6 inches above outside grade[][][][][][]]

A

C. 12 inches above the floor.

40
Q

What type of water heater is approved for installation in a bathroom?

A. Maximum 10 gal underfired storage type

B. Maximum 30 gal underfired storage type

C. Instantaneous types[][][][][][][][][][][][][][][][][][][]]

D. Direct vent types[][][][][][][][][][][][][][][][][][][][][][]]

A

D. Direct vent types.

41
Q

The minimum clearance to combustible material for an underfired storage type water heater shall be:

A. 2 inches.

B. 4 inches.

C. 6 inches.

D. 12 inches.

A

A. 2 inches.

42
Q

The minimum service clearance for the burners on a domestic underfired storage hot water tank is:

A. 12 inches.

B. 24 inches.

C. 36 inches.

D. 48 inches.

A

B. 24 inches.

43
Q

A boiler shall be installed with a minimum clearance to combustibles from the side of:

A. 6 inches.

B. 12 inches.

C. 18 inches.

D. 24 inches.

A

C. 18 inches.

44
Q

A boiler shall be installed with a minimum clearance from combustibles to the burner of:

A. 12 inches.

B. 24 inches.

C. 36 inches.

D. 48 inches.

A

D. 48 inches.

45
Q

A hot water boiler should have the high limit aquastat (with manual reset) set at a tempurature:

A. 20° below the operating aquastat set point.

B. equal to the operating aquastat set point[][][]

C. 20°F above the operating aquastat set point.

D. 40°F above the operating aquastat set point.

A

C. 20°F above the operating aquastat set point.

46
Q

When adjusting the fan control of a forced air furnace, which of the following is a normal temperature for the “fan on” set point?

A. 70°F.

B. 90°F.

C. 110°F.

D. 130°F.

A

C. 110°F.

47
Q

The moisture duct for a domestic cloths dryer shall not terminate within __ feet of a fresh air intake.

A. 3 feet.

B. 5 feet.

C. 10 feet.

D. 15 feet.

A

A. 3 feet.

48
Q

The moisture duct for a commercial cloths dryer shall not terminate within _____ of a fresh air intake.

A. 3 feet.

B. 5 feet.

C. 10 feet.

D. 15 feet.

A

C. 10 feet.

49
Q

Most domestic gas ranges require 120 volts for the operation of the:

A. Main oven gas valve.

B. Standing pilot burner.

C. Clock[][][][][][][][][][][][][][][][]

D. Oven temperature control.

A

C. Clock.

50
Q

On the top burner of a domestic gas range, which part of the flame can impinge on the heating surface of a pot without causing soot or carbon monoxide?

A. Inner cone.

B. Outer cone.

C. Inner mantel.

D. Outer mantel.

A

D. Outer mantel.

51
Q

A residential type range shall have the following minimum clearance from combustibles materials above of:

A. 12 inches.

B. 18 inches.

C. 24 inches.

D. 30 inches.

A

D. 30 inches.

52
Q

A commercial gas range shall maintain a clearance between the top burner flame and an adjacent deep fryer of at least:

A. 6 inches.

B. 12 inches.

C. 16 inches[]

D. 24 inches.

A

C. 16 inches.

53
Q

Infrared burners should be mounted no more than _______ from horizontal.

A. 15 degrees.

B. 30 degrees.

C. 45 degrees.

D. 60 degrees.

A

B. 30 degrees.

54
Q

An unvented type infrared heater shall be provided with mechanical ventilation to prevent carbon dioxide levels from reaching levels of:

A. 200 ppm.

B. 2,000 ppm.

C. 5,000 ppm.

D. 10 percent[]]

A

C. 5,000 ppm.

55
Q

A furnace through which the circulating air flows in the opposite direction to the flue gas is a(an):

A. Floor furnace.

B. Horizontal furnace.

C. Counter flow furnace.

D. Attic furnace[][][][][][][][]]

A

C. Counter flow furnace.

56
Q

The instantaneous water heater is activated by:

A. Lighting the pilot.

B. Water pressure[][]

C. Gas pressure[][][][]

D. Water flow[][][][][][][]

A

D. Water flow.

57
Q

A hot plate must be connected to a gas line with:

A. An approved hose.

B. An approved flexible connection.

C. Rigid pipe[][][][][][][][][][][][][][][][][][][][][][]

D. Semi-rigid pipe[][][][][][][][][][][][][][][][][]

A

C. Rigid pipe.

58
Q

The minimum input to a top burner on a gas range is adjusted by:

A. Adjusting the internal by-pass screw.

B. Adjusting the adjustable orifice[][][][][]]

C. Realignment of the temperature control dial.

D. Altering the setting on the gas pressure regulator.

A

A. Adjusting the internal by-pass screw.

59
Q

A low temperature gas oven is one that:

A. Cooks food quickly at low temperature.

B. Can operate in a low temperature environment.

C. Can maintain an oven temperature of 140°F[][][][][]

D. Modulates burner input to maintain low temperature.

A

C. Can maintain an oven temperature of 140°F.

60
Q

A top burner on a gas range is operating correctly. When the oven is turn on, the top burner goes out. The most probable cause is:

A. The oven is overfiring and using too much gas

B. The seals around the oven vent or door may be damaged and leaking.

C. The burner by-pass adjustment is not correct[][][][][][][][][][][][][][][][][][][][][][][][]]

D. The oven temperature control is inoperative[][][][][][][][][][][][][][][][][][][][][][][][][]

A

B. The seals around the oven vent or door may be damaged and leaking.

61
Q

The purpose of the oven heater pilot is to:

A. Keep the oven at an even temperature.

B. Act as a continuous pilot when the oven is off.

C. Heat the oven temperature controller on a call for heat.

D. Heat the oven control capillary on a call for heat[][][][][][][]

A

D. Heat the oven control capillary on a call for heat.

62
Q

A direct-fired door air heater shall be interlocked with associated doors so that the heater can only operate when the door is at least:

A. 30 percent open.

B. 50 percent open.

C. 80 percent open.

D. 100 percent open.

A

C. 80 percent open.

63
Q

True or False?

The figure below is a counterflow forced warm air furnace.

A

True.

64
Q

If a furnace is installed in a repair garage:

A. The pilot must be at least 4 1/2 feet above the burner.

B. The draft control device must be in a seperate room[]

C. The appliance s/o valve must be in a seperate room[]

D. The burner must be at least 4 1/2 feet above the floor.

A

D. The burner must be at least 4 1/2 feet above the floor.

65
Q

When can a used furnace be installed?

A. Never.

B. When inspected and approved by the local gas inspectors.

C. When inspected and found safe by the installing gas fitter[]

D. When inspected and approved by the homeowner[][][][][][][][]

A

C. When inspected and found safe by the installing gas fitter.

66
Q

Domestic gas ranges require a minimum clearance from combustables of __ above the cooking top.

A. 18”.

B. 24”.

C. 30”.

D. 36”.

A

C. 30”.

67
Q

On the oven of a low-tempurature domestic gas range:

A. The main burner modulates to its minimum flame position.

B. The main burner goes out completely when the setpoint tempurature is reached.

C. The main burner is ignited by a hot surface igniter[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]

D. All pilots go out during the cycle[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]

A

B. The main burner goes out completely when the setpoint tempurature is reached.

68
Q

A properly sized unit heater is installed in a warehouse but the customer complains of insufficient heat. The gas fitter should:

A. Clock the appliance to see if it is underfired.

B. Slow down the fan speed to allow the heat exchanger to get hotter.

C. Adjust the plenum switch from 110°F to 200°F[][][][][][][][][][][][][][][][][][][][][][][][]]

D Advise the customer to seal all cracks and openings in the warehouse.

A

A. Clock the appliance to see if it is underfired.

69
Q

True or False?

A porous refractory, such as ceramic, acts as the radiating surface of the burner in an infrared heater.

A

True.

70
Q

Referring to the figure below, it is:

A. A solenoid gas valve.

B. An automatic vent damper.

C. A manually adjustable vent damper.

D. A barometric damper[][][][][][][][][][][][][][]

A

B. An automatic vent damper.

71
Q

Referring to the figure below, it is:

A. A control module.

B. An electronic timer.

C. An electronic thermostat.

D. A high limit switch[][][][][][]]

A

A. A control module.

72
Q

The maximum input to a top burner on a gas range is adjusted by:

A. Adjusting the primary air setting.

B. Adjusting the cap orifice[][][][][][][]]

C. Increasing or decreasing the house line pressure.

D. Adjusting the burner spoiler screw[][][][][][][][][][][][][][]

A

B. Adjusting the cap orifice.

73
Q

The minimum clearance from combustables for a boiler are:

A. 2” Vertical; 2” Sides and Rear; 24” Front.

B. 12” Vertical; 12” Sides and Rear; 18” Front.

C. 18” Vertical; 18” Sides and Rear” 24” Front.

D. 18” Vertical; 18” Sides and Rear; 48” Front.

A

D. 18” Vertical; 18” Sides and Rear; 48” Front.

74
Q

A commercial cloths dryer should not be installed closer than __ from combustables.

A. 2”.

B. 6”.

C. 18”.

D. 48”.

A

C. 18”.

75
Q

The minimum clearance from combustables for a residential cloths dryer are:

A. 6” Above; 24” Front; 6” Back and Sides.

B. 2” Above; 24” Front; 2” Back and Sides.

C. 12” Above; 24” Front; 4” Back and Sides.

D. 18” Above; 24” Front; 36” Back and Sides.

A

A. 6” Above; 24” Front; 6” Back and Sides.

76
Q

Referring to the figure below, it is:

A. A wall-hung instantaneous hot water heater.

B. A mid-efficiency condensing furnace[][][][][][][]

C. A high-efficiency radiant heater[][][][][][][][][][][][]

D. A wall-hung towel warmer[][][][][][][][][][][][][][][][]]

A

A. A wall-hung instantaneous hot water heater.

77
Q

The minimum clearance from a combustable for a hot water fired heater that is not classified as an underfired storage type water heater is:

A. 1”.

B. 2”.

C. 6”.

D. 12”.

A

C. 6”.

78
Q

Referring to the figure below, it is:

A. An upflow forced warm air furnace.

B. A downflow forced warm air furnace.

C. A counterflow forced warm air furnace.

D. A Recessed wall furnace[][][][][][][][][][][][]]

A

A. An upflow forced warm air furnace.

79
Q

With specific reference to forced warm air furnaces, plugged filter in the return air plenum arould cause:

A. The burner to run continuously.

B. The thermostat contacts to open.

C. The fan motor to stop operating[].

D. The limit switch to cycle on and off.

A

D. The limit switch to cycle on and off.

80
Q

Unless specified by the manufacturer, the high limit on a forced hot water boiler should not be set higher than:

A. 250°F.

B. 200°F.

C. 180°F[].

D. 140°F[].

A

B. 200°F.

Course L (30 decks)

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