Maintenance

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Congratulations - you have completed Maintenance. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%

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Question 1

When servicing a gas furnace, _____ should be allowed to elapse after shutting off the gas supply.

A	thirty seconds
B	five minutes
C	two minutes
D	one minute

Question 2

Be especially careful if a leak is suspected in an LP gas appliance because LP _____.

A	is odorless, so you don't know if you are inhaling it
B	explodes when it comes into contact with air
C	appliances operate under extremely high pressure
D	is heavier than air and therefore will not disperse without forced ventilation

Question 3

A hazard associated with rodents is _____.

A	cryptococcosis
B	histoplasmosis
C	chlamydia
D	hantavirus

Question 4

If the burner flame on a natural gas furnace is a soft blue, it is a sign of _____.

A	low manifold pressure
B	normal operation
C	too little primary air
D	too much primary air

Question 5

When checking the burner flame on an LP gas furnace with a single-stage regulator, remember that _____.

A	LP gas uses a different sized orifice than natural gas
B	LP burns yellow rather than blue
C	the supply tank must be at least half full to obtain a reliable reading
D	the manifold pressure for an LP system is much lower than that for a natural gas system

Question 6

A hard, sharp pilot flame in a natural gas furnace usually indicates _____.

A	the pilot is operating normally
B	the orifice is too small
C	there is excessive draft near the pilot
D	the gas pressure is too low

Question 7

Which of the following is likely to be caused by low manifold pressure in a gas furnace?

A	Damage to heat exchangers from overfiring
B	Excessive flue gas temperatures
C	Short cycling
D	Condensation and rusting in heat exchangers

Question 8

For gas furnaces equipped with a pilot flame assembly, the pilot flame should cover the thermocouple tip for a distance of _____.

A	3/8" to 1/2"
B	1/2" to 5/8"
C	1/8" to 1/4"
D	1/4" to 3/8"

Question 9

The temperature rise of a furnace is the temperature difference between the _____.

A	thermostat setpoint and the actual room temperature
B	supply air temperature and the thermostat setpoint
C	return air and the supply air
D	combustion air intake and the flue gases

Question 10

The purpose of using a fiber-optic borescope when servicing a gas furnace is to _____.

A	check the heat exchangers for leaks
B	change the color of the burner flame
C	make sure there are no obstructions in the heat exchangers
D	make sure there are no obstructions in the furnace supply air plenum

Question 11

For battery-operated programmable thermostats, it is good practice to _____.

A	record programming before replacing the batteries
B	clean the electronic contacts
C	always adjust the cycle rate
D	replace the batteries semiannually

Question 12

In furnaces that use an HSI, the HSI energizes when ____________.

A	inducer airflow is detected
B	the flame detector is active
C	the thermostat calls for heat
D	the gas valve energizes

Question 13

The static pressure drop for the evaporator of a cooling system is measured across the _____.

A	evaporator and blower
B	evaporator
C	filters and evaporator
D	blower

Question 14

If the static pressure drop across the evaporator of a cooling system is too high, it should be corrected by _____.

A	replacing the evaporator
B	decreasing the cooling load
C	cleaning the evaporator coil
D	adjusting the blower fan speed

Question 15

The subcooling tolerance for a properly operating cooling system is normally _____.

A	±7°F
B	±1°F
C	±5°F
D	±3°F

Question 16

A cooling check on a heat pump should only be made when the temperature is _____.

A	below 50°F
B	above 50°F
C	below 70°F
D	above 70°F

Question 17

If after energizing the furnace blower the electronic air cleaner is not operating and its light is off, the _____ may be faulty.

A	airflow probe
B	blower interlock switch
C	sail switch
D	differential pressure switch

Question 18

The best cleaning solution for a very dirty permanent air filter is _____.

A	kerosene
B	warm, soapy water
C	carpet shampoo
D	carbon tetrachloride

Question 19

For optimum permanent filter performance, filter abrasive should be applied by _____ the filter.

A	spraying
B	hand coating
C	dipping
D	brushing it on

Question 20

A method for getting rid of rodent and bird droppings and nesting materials that may harbor viruses is to _____.

A	use a vacuum cleaner
B	soak the material with disinfectant or 10 percent bleach solution, then remove it
C	immediately contact the state environmental protection agency and let them remove it
D	sweep the material up with a broom, then pick it up with a cloth soaked in disinfectant or bleach solution

Question 21

The proper manifold pressure for natural gas is _____ in. w.c.

A	1.0 to 2.0
B	4.0 to 5.0
C	3.0 to 4.0
D	2.0 to 3.0

Question 22

The device used to prove a flame in a system with a hot surface ignitor is a _____.

A	cad cell
B	thermocouple
C	heat sensing element
D	flame sensor

Question 23

Operating a heating appliance with a temperature differential above the manufacturer's specified range can result in _____.

A	a cracked heat exchanger
B	combustion chamber explosions
C	damaged burners or nozzles
D	damaged ignitors or electrodes

Question 24

Dry bearings can cause

A	excessive voltage to a motor.
B	an increase in efficiency
C	an increase in amperage.
D	a decrease in amperage

Question 25

The sleeve in a sleeve bearing is commonly made of

A	Copper
B	Bronze
C	Silver
D	Iron

Question 26

An oil type motor typically requires oiling every

A	1 to 3 months
B	3 to 6 months
C	12 months
D	18 months

Question 27

What type of bearing can handle a larger load?

A	Sleeve bearing
B	Bushing
C	Ball bearing
D	Axial bearings

Question 28

Increasing the pitch of a axial fan blade will

A	Increase the amperage of a fan motor
B	Decrease the amperage of a fan motor
C	Increase the torque of a fan motor
D	Increase the rpms of a fan motor

Question 29

Changing a condenser fan blade from a 4 to 5 blade will

A	Increase the amperage of a fan motor
B	Decrease the amperage of a fan motor
C	Increase the torque of a fan motor
D	Increase the rpm of a fan motor

Question 30

As the air volume is decreased over a fan, the motor amperage will

A	increase
B	Decrease
C	Stay the same
D	Air volume cannot be changed

Question 31

Direct-drive condenser fans that are lower then 5 horsepower are commonly

A	Three-phase motor
B	PSC motor
C	CSIR motor
D	CSCR motor

Question 32

How are condenser fan motors cycled during low ambient conditions?

A	By the use of a high ambient pressure switch
B	By the use of a low pressure switch
C	By the use of a high pressure switch
D	By the use of a reverse acting high pressure switch

Question 33

Why is it necessary to cycle the condenser fans during low ambient conditions?

A	To prevent an increase in high side pressure and the flooding of the evaporator coil.
B	To prevent a decrease in high side pressure and the flooding of the evaporator coil.
C	To prevent an increase in high side pressure and the starving of the evaporator coil.
D	To prevent a decrease in high side pressure and the starving of the evaporator coil.

Question 34

Belt drive blower motors lower than 5 horse power commonly use a

A	Three-phase motor
B	PSC motor
C	CSIR motor
D	CSCR motor

Question 35

What is the color of the low speed on a 120 volt, 3 speed motor?

A	Green
B	White
C	Red
D	Black

Question 36

What is the color of the high speed on a 120 volt, 3 speed motor?

A	Green
B	White
C	Red
D	Black

Question 37

What is the color of the common lead on a 120 volt, 3 speed motor?

A	Green
B	White
C	Red
D	Black

Question 38

A fan motor that operates at 1,050 rpm and has a pulley size of 6” operates a blower that has a pulley size of 9”. What is the rpm of the blower

A	1,500
B	1,575
C	775
D	700

Question 38 Explanation:

Blower RPM = DRIVE PULLEY RPM/BLOWER PULLEY RPM X MOTOR RPM

Question 39

How many cfm must a blower provide per ton of refrigeration?

A	300
B	400
C	600
D	800

Question 40

How does an increased static pressure in a duct system affect the blower motor?

A	The amperage increases
B	The amperage decreases
C	The air quantity increases
D	The air quantity decreases

Question 41

What are two common fans that are used on residential air conditioning systems?

A	Centrifugal and rotary
B	Axial and reverse rotary
C	Squirrel cage and a centrifugal
D	Axial and squirrel cage

Question 42

What is the FLA of a motor?

A	Starting amperage
B	Running amperage
C	Counterelectromotive force amperage
D	Fully locked amperage

Question 43

What is the LRA of a motor?

A	Starting amperage
B	Running amperage
C	Counterelectromotive force amperage
D	Locked resistance amperage

Question 44

Common external static pressure for a residential furnace blower is

A	½”W.C.
B	1”W.C.
C	1 ½”W.C.
D	2”W.C.

Question 45

To reverse the direction of a three phase motor

A	Replace the motor
B	Reverse speed taps will have to changed
C	Reverse any two power leads
D	None of the above

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Maintenance

Maintenance

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