EPA 410A Safety

Question 1

Polyolester (POE) oils stored in plastic containers will:

A) separate
B) become more alkaline
C) become acidic
D) absorb moisture through the plastic

Answer 1

D) absorb moisture through the plastic

Question 2

R-407C has:

A) a foul odor
B) to be charged in the vapor phase
C) the ability to fractionate
D) no temperature glide

Answer 2

C) the ability to fractionate

Question 3

A condensing unit designed for use with R22:

A) must be replaced with a model designed for use with R-410A
B) cannot withstand the higher pressure of R-410A
C) both A and B
D) none of the above

Answer 3

C) both A and B

Question 4

In a refrigeration system, oil and refrigerant:

A) contain alkybenzene
B) mix with each other
C) do not touch each other
D) are not miscible

Answer 4

B) mix with each other

Question 5

Removal of refrigerant from a system can be accomplished by these two basic methods:

A) condensation and evaporation
B) dew point and bubble point
C) superheating and subcooling
D) active and passive

Answer 5

D) active and passive

Question 6

Ozone depletion is caused by:

A) HFCs
B) chlorine and bromine
C) R-410A refrigerants
D) all of the above

Answer 6

B) chlorine and bromine

Question 7

The cylinder code for R-407C is:

A) medium brown (chocolate)
B) light green
C) rose
D) light blue

Answer 7

A) medium brown (chocolate

Question 8

The receiver bypass:

A) prevents subcooled vapor from sitting in the receiver and losing its subcooling
B) prevents superheated liquid from sitting in the receiver and losing its superheat
C) prevents superheated vapor from sitting in the receiver and losing its superheat
D) prevents subcooled liquid from sitting in the receiver and losing its subcooling

Answer 8

D) prevents subcooled liquid from sitting in the receiver and losing its subcooling

Question 9

For commercial and industrial refrigeration systems, a __________ annual leak rate is considered a substantial leak.

A) 25%
B) 15%
C) 5%
D) 35%

Answer 9

D) 35%

Question 10

An overcharged system can cause:

A) frosted suction line
B) low compression ratio
C) high side pressure increase
D) high side pressure decrease

Answer 10

C) high side pressure increase

Question 11

Polyolester lubricants (POEs) are used extensively with:

A) HFCs
B) lawn mowers
C) HCFCs
D) CFCs

Answer 11

A) HFCs

Question 12

Technicians handling liquid refrigerant should wear gloves and:

A) steel-toe boots
B) self contained breathing apparatus (SCBA)
C) hearing protection
D) approved eye protection

Answer 12

D) approved eye protection

Question 13

R-407C pressures and temperatures are similar to:

A) R-22
B) R-12
C) R-502
D) R-134a

Answer 13

A) R-22

Question 14

Whenever possible, to avoid fractionation, charging of a refrigeration system incorporating a near-azeotropic blend should be done with:

A) liquid refrigerant
B) a scroll compressor
C) R-22
D) a yellow and gray recovery cylinder

Answer 14

A) liquid refrigerant

Question 15

Liquid lines used with R-22:

A) may only be used with R410A in dry climates
B) may never be used with R-410A
C) may be used with R-410A if sized and properly cleaned
D) may be used with R-410A without additional considerations

Answer 15

C) may be used with R-410A if sized and properly cleaned

Question 16

If R-410A is ingested:

A) immediately inject trioxide compound
B) drink milk
C) do not induce vomiting
D) induce vomiting

Answer 16

C) do not induce vomiting

Question 17

Which refrigerant has an ozone depletion potential of zero?

A) R-22
B) HCFC-22
C) CFC-11
D) R-134A

Answer 17

D) R-134A

Question 18

An advantage of ester-based oils such as Polyolester is:

A) they have a wax-free composition
B) they have low miscibility with R-410
C) they are very hygroscopic
D) they trap moisture

Answer 18

A) they have a wax-free composition

Question 19

Polyalkylene Glycol (PAG) oils:

A) are non-toxic if inhaled
B) are extremely hygroscopic
C) perform well in aluminum-on-steel applications
D) all of the above

Answer 19

B) are extremely hygroscopic

Question 20

Charging a R-410A system until the sight glass is clear may result in:

A) compressor damage
B) system overcharge
C) proper charge
D) both A and B

Answer 20

D) both A and B

Question 21

The temperature of a single compound at 100% saturated vapor with no superheat is:

A) greater than its saturation temperature for that pressure
B) equal to its saturation temperature for that pressure
C) less than its saturation temperature for that pressure
D) none of the above

Answer 21

B) equal to its saturation temperature for that pressure

Question 22

R-410A systems may be topped off after a leak because:

A) it has a very high temperature glide
B) its cylinder is rose
C) it must be weighed in
D) it behaves like a pure compound

Answer 22

D) it behaves like a pure compound

Question 23

To find the correct saturation temperature for a given pressure, its best to use:

A) the dew point
B) the compression ratio formula
C) a gauge manifold
D) a pressure/temperature chart

Answer 23

D) a pressure/temperature chart

Question 24

Temperature glide can range from:

A) 0.2 deg to 16 deg F
B) -3 deg to 8 deg F
C) 5 deg to 16 deg F
D) 5.6 deg to 20 deg F

Answer 24

A) 0.2 deg to 16 deg F

Question 25

A liquid changes to a vapor by absorbing:

A) sensible heat
B) superheat
C) moisture
D) latent heat

Answer 25

D) latent heat