gas exam

73, a pilot with primary air is called

An aerated pilot

As more excess air is added

Co2 goes down, o2 goes up

38. improper pressure can have what negative effect?

Co2 production, rollout and shorten unit's life

gas fired refrigerators must incorporate what safety?

High limit and CO detector

75, this type of furnace has its blower section lateral to (beside) the heat exchanger

Low boy, horizontal furnace

84. Select the example that best describes how a lower heated medium temp affects an appliances natural draft venting system

Low supply air temperature in a furnace absorbs too much of the flue gas heat, decreasing flue gas temp and reducting draft.

a forced draft motor Is upstream of the combustion zone, creating a negative pressure in the appliance Is downstream of the combustion zone, creating a positive pressure in the appliance Is part of the burner and affects combustion air, not the venting

*None of the above

an inducer motor Is upstream of the combustion zone, creating a negative pressure in the appliance Is downstream of the combustion zone, creating a positive pressure in the appliance Is part of the burner and affects combustion air, not the venting

*None of the above

95, every chimney, or A vent, must have

A clean out

101, which of the following statements is correct?

None of the above

80. a natural draft burner system operate because

None of the above

what is the purpose of the appliance regulator?

None of the above

the purpose and function of a regulator is

Reduce and maintain pressure appropriate to the appliance

35, what could burnt wiring found during an inspection indicate?

Roll out, a corrosive environment, and excessive current/resistance

39, the following in NOT a type of regulator

Rotary style

72. a burner that supplies air under pressure and gas at atmospheric pressure would use what kind of regulator?

Zero governor

Define primary air

air that is mixed with the fuel prior to combustion

13, where electrical current passes through an element which heats to ignite the gas is commonly referred to as

HSI

Diaphragm meters

Have "bellows", as one fills the other empties

List the 3 common purposes of a burner

Mix fuel and air, ignite it, remove products of combustion

22. what causes the contacts on a pressuretrol to open?

Setpoint

44. lock up is

The amount of pressure above setpoint where the regulator shuts closes

18. a flame rectification system uses what as a conductor?

The flame

74. flame rod rectification uses what to get DC?

The flame

81, natural draft venting systems operate because

The higher temp flue products create a positive pressure and rise towards the lower pressure area

34. when making a conversion from one gas to another, what must be noted on the rating plate?

The new type of gas

47, setpoint, in reference to a regulator pressure relief, is

The point at which the relief device begins to open

46 .when a servo regulator is fully closed, it is because:

The pressure over and under the diaphragm are the same

7, explain turn down ratio

The ratio to which a burner may be throttled or modulated...........

83, in induced draft system where the motor is in the appliance has its venting structure

Under position pressure

30. how does a duct heater differ from a unit heater?

Unit heater do not have ductwork

61, a direct operated pressure relief senses

Upstream pressure

23, a probe type low water cut off uses what as the conductor

Water

70. a high stack temperature indicates

We aren't effectively transferring energy to our medium

77CO2

...Is a non-toxic, asphyxiating gas that is formed during combustion

59, a natural gas regulator vent line NOT using a certified over pressurization device must be how far from a mechanical air intake?

10 ft

56. the maximum gas pressure allowed into the boiler room of a commercial building is

20 psig

3, Define secondary air

Air that is mixed with the fuel at the point of combustion

17, a thermistor is a

Device that has its resistance change based on temp

69, as more excess air is added

Efficiency increases

98. a mid effiecient gas fired recessed wall furnace would use which of the following venting

BW vent

49, a typical service regulator has what kind of relief?

Internal

58. the venting of a pressure control device shall be of sufficient size as to not cause impedance upon the:

Regulator

24. roll out differ from high limits on account that they...

Roll outs must be manually reset and high limits are automatic

48. a direct acting relief

Senses upstream pressure and relieves top atmosphere

63, if the relief valve setpoint is set lower than the regulator lockup pressure

The relief valve will never close

33, when making a conversion from LP to NG, the orifices will need to be.....

The same, but the pressure will need to change as NG operates off 7.0" WC and LP off 11.0" WC

29, what is the purpose of an expansion tank?

To allow for the expansion of water in a boiler loop

78. as condensation occurs in an appliance, what type of acid may form?

Carbonic

Define atmospheric burner

no mechanical means of adding combustion air

28. what is a "low boy" furnace?

Burner section is beside the blower compartment

87, a draft hood

Ensures excessive air is not drawn through the burner

79, combustion products do not include what

Excess air

85, select the example that best describes how excess air affects an appliances natural draft venting system

Excess air decreases flue gas temperature, increases the flue gas flow rates

86. a draft control device is used to limit draft because

Excessive draft can cause high flue gas rates and decrease efficiency

103, condensation forms when

Excessive heat is absorbed from the products of combustion, causing the vapour to recondense and form H2o

What is one main difference between a fan assist system and a power burner?

Fan assist systems are downstream OF COMBUSTION CHAMBER ......

a fan/limit control has 3 sets of contacts. They are what in correct order

Fan off, fan on, high limit

62. the set point of an internal relief valve is adjusted by:

It is not adjustable

15, the "bulb and bellows" flame sensing device relies on the expansion of what in the bulb?

Liquid

8. what is a nozzle mix burner

Primary air and fuel is mixed at the nozzle under pressure

10. the following type of pilot system would employ a means of verification prior to ignition

Proven type

66. we provide excess air to the combustion process to ensure:

That we have complete combustion

19, flame is proven in a rectification system because

The conversion of AC to DC

65, if vapour is drawn out of a propane tank

The decrease in pressure lowers the boiling point of the liquid, which then vaporizes and builds pressure

91, with a single pipe induced draft appliance, if the pressure indoors becomes excessively negative

The venting action could be reversed, causing spillage

14. the coefficient of expansion of a metal is its

Its calculated rate of expansion in change of temp.

43, the spring is

An opening force

31, what device maintains setpoint in a steam boiler

Pressuretrol

55, in a repair garage, how far off the ground must the source of ignition be?

54" (4 ft and half)

54. a unit 400k BTU or less that is certified to be installed on a non combustible floor may be installed on a combustible floor provided that its masonry units extended

6" beyond the sides of the appliance

9, the following type of pilot would have a primary air opening built into it

Aerated

5, define premix burner

Air and fuel are mixed mechanically prior to combustion

102. direct vent systems

Also called sealed combustion, also called 2 pipe, and are unaffected by indoor pressure changes

93, which of the following is a logical sequence of operation for an induced draft furnace?

Call for heat, inducer motor starts, pressure switch closes, ignition device energizes, gas valve energizes

71, a burner that supplies air under pressure and gas at atmospheric pressure is called a

Aspirator burner

97, a standard mid-efficiency gas fired appliance that relies on natural draft venting would use what type of venting material?

B vent

100. a gas fired furnace with a forced draft motor in the appliance would use which of the following venting materials?

BH vent

99, a gas fired furnace with an inducer motor in the appliance would use which of the following venting materials?

BH vent

Which of the following materials may NOT be used in a gas piping or tubing system?

Brass

45, a balanced regulator is designed to

Buffers high inlet pressure swings

51, meter and regulator installations shall be accordance with

CSA Z662

52. the installation of gas burning appliances and supply piping in mobile homes shall be in accordance with

CSA z240.4.1

76. due to the high input and low inlet water temp., what is a large concern with pool heaters?

Condensation

40. what is the purpose of a line regulator?

To reduce building line pressure even further

96. why are chimney liners used

Flue gases from natural gas appliances are lower temp, requiring smaller venting

12. the source of ignition is present during the entire call for heat is the definition of

Intermittent ignition

88. a barometric damper

Is used on systems that maintain a negative pressure over burner

42. the four common elements of a regulator are:

Measuring element, orifice, spring, and vent

11, define Piezoelectric

Mechanical force is applied to a substance which generates electricity when compressed/deformed

57, when a line pressure regulator is required and the inlet supply pressure to the regulator exceeds. 0.5 psig, it shall be of the:

Positive shut-off type

50. a monitoring system

Two regulators in series, both sensing downstream pressure at roughly the same point

92. an induced draft system where the motor is at the termination has its venting structure

Under negative pressure

16. if the flame goes out, how does a thermocouple system stop the flow of gas?

With no flame, it means of electrical generation is gone the solenoid disengages and the flow of gas ceases.