Brainscape's Knowledge GenomeTM

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


See full index

HVAC Tools Exam > Practice > Flashcards

Practice Flashcards

1
Q

T or F

Calcium Chloride Brine Solutions are suitable for food processing applications because it uses simple table salt in it’s mixture

A

False

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

T or F

When using an electric float for the control of ammonia systems a needle vive must always be used to control the amount of liquid refrigerant entering the chiller, this valve is normally located up stream of from the liquid line solenoid valve

A

True

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

T or F

Calcium Chloride may be stored in the same location or equipment room as ammonia as long as there is no direct source of heat

A

False

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

T or F

Copper or brass may be used in ammonia systems as long as there is no moisture present in the equipment room

A

False

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

T or F

The minimum test pressure for the “low side” of an air cooled ammonia system is equal to or greater than the setting pressure of the relief device

A

False

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

T or F

Cascading is desirable if system temperatures of lower than -125F are required

A

True

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

The liquid recirculating pump as used with two stage liquid recirculation ammonia systems is located between the:

a) compressor and receiver
b) low pressure and high pressure receiver
c) low press receiver and evaporator
d) high press receiver and evaporator

A

low pressure receiver and evaporator

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

The boiling point of R-717 at atmospheric pressure is

a) -28C
b) -27.6F
c) -28F
d) -27.6F

A

-28F

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

When installing globe valves in any system for component isolation, how should they be installed on horizontal line runs?

a) valve stem should be vertical to line run
b) stem should be horizontal to line run
c) stem may be in any position as long as high press side of system is exerted on bottom side of seat assembly
d) stem should be at right angles to horizontal run of pipe and the high press side exerted on bottom side of seat assembly

A

stem should be at right angle to horizontal run of pipe

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

What component is not normally required in cascade systems?

a) condenser
b) receiver
c) refrigerant flow control on secondary coil
d) low stage condenser

A

receiver

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

Which type of intercooler is not suitable for ammonia compression systems?

a) dry type
b) shell and coil
c) open type
d) any of the above are suitable

A

dry type

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

Multi-stage or booster compression systems are normally required for low temp applications such as ammonia blast freezers. This type of compression system is normally good for applications above -90F and should be used if the reciprocating compression ratio of a single stage system exceeds:

a) 20:1
b) 10:1
c) 5:1
d) 3:1

A

10:1

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

Multi-stage cascade systems can be divided into two major groups which are

a) cascade or extra low
b) cascade or multi-stage
c) cascade or direct
d) any of the above could be considered correct

A

cascade or direct

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

An ammonia receiver has the following dimensions 3ft x 60” long. What is the correct PRV capacity? Factor for R718 = 1, For R-717 = 0.5

a) 90cu/ft/min
b) 90 lbs/min
c) 7.5 cu/ft/min
d) 7.5 lbs/min

A

7.5lbs/min

C=FDL (60”/12”) to get feet

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

The corrosiveness of a brine or eutectic mixture should be maintain between _____ and ______ and can be determined by a PH tester

a) 7 and 6.5
b) 7 and 7.5
c) 7 and 8.5
d) none of the above

A

7 and 8.5

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

The normally temperature drop through a low temperature chiller is normally:

a) 2C at a flow rate of 10 to 15gals/ton
b) 2F at a flow rate of 10 to 15gals/ton
c) 10F at a flow rate of 2 to 9 gals/ton
d) 10C at a flow rate of 2 to 9 gals/ton

A

2F at a flow rate of 10 to 15 gals/ton

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

Normally ice temperature is cooled by a brine thermostat (return temperature). If your saturated suction temperature is 8F, what should your actual ice temperature be at?

a) 18F
b) 18C
c) 28F
d) 28C

A

28F

18
Q

Centrifugal pumps are widely used in the industry. What device can be found in the stuffing box of a centrifugal pump that has no moving parts?

a) sleeve bearing
b) ball type bearing
c) mechanical seal
d) packing gland

A

packing gland

19
Q

Choose the correct statements for the flowing with respect to closed circuit and direct contact cooling towers:

  1. closed circuit condenser water is not exposed to atmosphere
  2. direct contact condenser water is not exposed to atmosphere
  3. closed circuit condenser water is exposed to atmosphere
  4. direct contact condenser water is exposed to atmosphere

a) 1&2
b) 1&3
c) 1&4
d) 3&4

A

1 & 4

20
Q

What is the importance of the fill material as used in cooling tower designs and construction?

a) fill adds to the surface area of the cooling tower
b) fill directs the air through the cooling tower
c) fill provides for filtration for the cooling tower
d) fill adds weight to the cooling tower

A

a) fill adds to the surface area of the cooling tower

21
Q

Identify two types of fill material used

a) cedar strips and polyvinylchloride
b) polyethylene and fiber re-enforced polyester
c) film and steel
d) polyurethane and acetate film

A

a) cedar strips and polyvinylchloride

22
Q

What is the term used for a mixture of salt and water to lower its freezing temperature below 32F?

a) eutectic mixture
b) brine
c) glycol
d) wort

A

b) brine

23
Q

Under what condition should the operator or service technician wear a self-contained breathing apparatus into an ammonia equipment room?

a) 25ppm
b) 50ppm
c) 200ppm
d) 300ppm

A

d) 300ppm

24
Q

What is the most common secondary refrigerant used in an air conditioning application?

a) brine
b) glycol
c) refrigerant
d) water

A

d) water

25
Q

What is the particular code requirement with regards to construction of a fire valve box for a class T machinery room?

a) it is painted red
b) it has steel front and sides
c) it has a glass front
d) it is paced at the six foot level

A

c) it has a glass front

26
Q

What is the term used to describe constant dilution of cooling tower sump water?

a) blowdown
b) bleed water
c) make up water
d) float angle

A

b) bleed water

27
Q

A microprocessor controller analyzes the conductivity of the cooling tower sump water. When the electrical conductivity is high what maintenance must be performed?

a) nothing, no maintenance required as this indicates clean water
b) indicates water is acidic and ph should be adjusted
c) indicated the water is too warm and needs to be cooled
d) indicates water is contaminated and must be drained and re-filled

A

d) indicates water is contaminated and must be drained and re-filled

28
Q

Where should the fire valve be located for a class T machinery room?

A

7.5 feet above the ground outside the class t machinery room

29
Q

The liquid leaving the pipe on the discharge side of the system is the?

A

point of free discharge

30
Q

Liquid entering the pump with the level below the centre line of the pump is the?

A

static suction lift

31
Q

feet?

A

head unit measurement

32
Q

the normal type of pump used in the industry?

A

centrifugal pump

33
Q

liquid entering the suction side of the pump

A

lift or head

34
Q

the pressure that the pump must overcome on the discharge

A

total static head

35
Q

the head that appears only when the liquid is moving

A

friction head

36
Q

pressure + velocity + friction heads

A

dynamic head

37
Q

the head that is measured only when the pump is off

A

static head

38
Q

dynamic + total static

A

total head

39
Q

identify 3 major groups of secondary refrigerants used in the industry

A

brines, glycol, alcohol

40
Q

According to B52 identify six design features that are required for an ammonia equipment room:

A
  1. at least one exit door to outer air
  2. shall be of tight construction
  3. no flame producing device over 427C
  4. exterior openings not under fire escapes
  5. walls, floors, ceilings 1 hour fire resistive construction
  6. independent mechanical ventilation system
41
Q

identify two methods of dehumidification for curling or skating rinks

A

refrigeration or desiccants

42
Q

Under what conditions should the operator or service technician wear an escape breathing aparatus into an ammonia equipment room?

A

service tech or operator should be carrying an escape respirator under all conditions

HVAC Tools Exam (4 decks)

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