Mechanical A/C Service Exam

Question 1

According to the ASHRAE refrigerant safety classification standard which designations would be the safest?

Answer 1

A-1

Question 2

When transporting cylinders containing used refrigerant, DOT requires that you?

Answer 2

Attach DOT classification tags

Question 3

What refrigeration compound have the highest ozone depletion potential (ODP)?

Answer 3

CFC’s

Question 4

Approved refrigerant recovery cylinders can be identified by which color code?

Answer 4

Yellow tops and grey bodies

Question 5

Under EPA’s regulations, what standard must reclaimed refrigerant meet before it can be resold?

Answer 5

ARI 700

Question 6

The sate of refrigerant entering the compressor of a refrigeration system is ____.

Answer 6

low pressure vapor

Question 7

Refrigerant that is cleaned using oil separation and single or multiple passes through devices, such as replaceable core filter-driers, which reduce moisture, acidity, and particulate matter is ____.

Answer 7

recycling

Question 8

What leak detection method is most effective for locating the general are of a small leak?

Answer 8

Electronic leak detector

Question 9

A compound pressure gauge for the low side of a system measures pressure in ____?

Answer 9

PSIG and inches of mercury

Question 10

When first inspecting a hermetic system known to be leaking you should look for?

Answer 10

traces of oil

Question 11

When charging a system with nitrogen ____?

Answer 11

only charge with nitrogen vapor and use a regulator

Question 12

Refrigerant entering the thermal expansion device of an R-22 heat pump is ____.

Answer 12

saturated or sub-cooled high pressure liquid

Question 13

Replacement of ____ is a repair which would always be considered major under EPA’s regulations.

Answer 13

an evaporator and condenser

Question 14

At high temperatures R-12 and R-22 can decompose to form ____.

Answer 14

hydrochloric and hydrofluoric acid and phosgene gas

Question 15

According to ASHRAE standard 15 a sensor and alarm are required for type A-1 refrigerants to sense ____.

Answer 15

oxygen deprivation

Question 16

A ____ is not a method presently used for checking the fill level in a recovery tank.

Answer 16

sight glass

Question 17

DOT Regulation 49 CFR requires that the ____ be recorded on the shipping paper for a hazard class 2.2 nonflammable compressed gases?

Answer 17

number of cylinders of each gas

Question 18

What is not a standard recommended safe work practice when recovering refrigerants.

Answer 18

wearing a respirator when working with refrigerants

Question 19

System dependent recovery equipment connote be used when?

Answer 19

the charge of the system is over 15 pounds

Question 20

Reclamation of a refrigerant means that it is ____.

Answer 20

processed so that it meets the standard for new refrigerant

Question 21

The principle of evacuating a system using a vacuum pump is to lower the system pressure so any moisture can ____.

Answer 21

boil off or vaporize

Question 22

Air in a refrigeration system mainly causes ___?

Answer 22

the system to work harder due to increase in condensing temperature
*over time it can also degrade the oil and cause acids to form

Question 23

The most accurate way to measure a vacuum is with a ____.

Answer 23

micron gauge

Question 24

What is the micron level to which a system should be evacuated down to?

Answer 24

500

Question 25

When charging refrigerant by weight you can charge with?

Answer 25

both liquid and vapor refrigerant

Question 26

The sub-cooling charging method gives an indication of the amount of ____?

Answer 26

liquid refrigerant at the expansion device

Question 27

What is the process called when each of the refrigerant used in a blended refrigerant leak at a different rate if released into the atmosphere changing the proportions of the refrigerants used in the blend?

Answer 27

fractionation

Question 28

After a leak in a system using a zoetrope refrigerant is repaired and the system has been evacuated the system should be charged with ____?

Answer 28

new refrigerant *its not possible to determine if the old refrigerant is the required blend

Question 29

When charging a system that uses a zoetrope refrigerant the system should be charged with _____.

Answer 29

liquid refrigerant

Question 30

When determining the type of burnout in a system with a hermetic compressor the fist thing to do is ____.

Answer 30

check the moisture and acid content of the system

Question 31

NEMA states three phase motors should operate successfully under running conditions at rated load when the voltage imbalance does not exceed ____.

Answer 31

1%

Question 32

A metering device is a refrigeration system control that ____.

Answer 32

converts high pressure high temperature liquid refrigerant to a low temperature low pressure mix of liquid and vapor refrigerant

Question 33

A significant difference between a DX evaporator and a flooded evaporator is ____.

Answer 33

in the DX evaporator the refrigerant is converted to vapor in the evaporator whereas it remains in liquid form in the flooded evaporator

Question 34

The correct location of a TXV sensing bulb is ____.

Answer 34

at the evaporator outlet

Question 35

What is the purpose of a crankcase heater?

Answer 35

to prevent liquid refrigerant from slugging the compressor

Question 36

What element in refrigerants causes ozone depletion?

Answer 36

chlorine

Question 37

The component directly following the evaporator of a refrigeration system is the ____.

Answer 37

accumulator

Question 38

When under a deep vacuum a hermetic refrigeration's compressor ____.

Answer 38

motor winding could be damaged if energized

Question 39

When evacuating a system, the use of a large vacuum pump could ____.

Answer 39

cause trapped water to freeze

Question 40

The component of a refrigeration system which converts a high pressure vapor to a high pressure liquid is the ____.

Answer 40

condenser

Question 41

Horizontal piping runs used in refrigeration systems should ____.

Answer 41

pitch down in the direction of refrigerant flow

Question 42

A compressor with a piston that travels back and forth in a cylinder is a ____.

Answer 42

reciprocating

Question 43

Components most often found in the refrigeration system liquid line are ____.

Answer 43

receiver, sight glass/moisture indicator, filter drier

Question 44

Annealed copper tubing shall not be used in normal sizes larger than ____.

Answer 44

2"

Question 45

The exhaust from a refrigeration equipment room shall not be less then ____ from a property line or opening into a building.

Answer 45

20 feet

Question 46

Operating a three phase electrical motor at a phase imbalance above ____ will most likely damage the motor.

Answer 46

5%

Question 47

The purpose of flux used in soldering is ____.

Answer 47

keeps the metal clean once soil has been removed

Question 48

Why are expansion valves adjustable?

Answer 48

to adjust for different altitudes and to adjust for different sizes of liquid receivers

Question 49

An ampere measures the flow of ____.

Answer 49

electrical current

Question 50

When an air conditioning system is not in operation, the accumulator should have adequate liquid holding capacity of not less than ____ percent of the entire system capacity.

Answer 50

50

Question 51

Open flame that comes in direct contact with R-22 creates ____.

Answer 51

phosgene gas

Question 52

Effective July 1, 1992 section 608 of the ____ prohibits individuals from intentionally venting ozone-depleting substances used as refrigerants.

Answer 52

Refrigeration Recycling Rule

Question 53

Section 608 does not consider small releases of refrigerant resulting from the disconnection of hoses, however, effective November 15, 1993 recovery and recycling equipment must be equipped with ____>

Answer 53

low-loss fittings

Question 54

Technicians repairing small appliances such as household refrigerators, window air conditioners, or water coolers must recover ___% of the refrigerant when the compressor is not operational and ____% when the compressor is operational.

Answer 54

80/90

Question 55

Refrigerant recovered or recycled can be returned to the same system or ____ without restriction.

Answer 55

systems owned by the same person

Question 56

Refrigeration systems in commercial and industrial process refrigeration sectors are required to repair leaks within ____ days when the equipment leaks at a rate that would release ____ percent or more of the charge over a year.

Answer 56

30/35

Question 57

Refrigeration systems in all sectors except commercial and industrial process refrigeration sectors are required to repair leaks that would release ____ percent or more of the charge over a year within 30 days of discovery.

Answer 57

15

Question 58

To translate psig to psia when using a temperature-pressure chart, ____ must be added.

Answer 58

14.7

Question 59

Refrigeration oil must be heated up to ____ degrees F before removing it from a system to minimize refrigerant release.

Answer 59

130

Question 60

The EPA Type I Certification is for ____

Answer 60

servicing small appliances (household refrigerator, window air conditioners)

Question 61

The EPA Type II Certification is for ____

Answer 61

servicing and disposing of high or very high pressure appliances except small appliances and MVAC's

Question 62

The EPA Type III Certification is for ____

Answer 62

servicing and disposing of low-pressure appliances