Deck 36: Heating and Air-Conditioning Service

Question 1

Sealants, the wrong dye, and flushing agents are all bad for air-conditioning systems.

Answer 1

True

Question 2

The material used for desiccants since the early eighties is a(n) ____________________ that will not crumble when wet.

Answer 2

molecular sieve

Question 3

Which of the following is LEAST-Likely to be a component of the clutch and compressor?

A)Gaskets
B)Snapring
C)Armature
D)Front plate

Answer 3

C

Question 4

The pressure reading in the system when it is not operating is called ____________________.

Question 5

While having a discussion, Technician A says that PAG oil can damage some paints. Technician B says that If PAG oil leaks, it will corrode fittings. Who is correct?

A)A only
B)B only
C)Both A and B
D)Neither A nor B

Question 6

While having a discussion, Technician A says that a desiccant becomes saturated when it becomes full of water. Technician B says that on a day with 80% humidity, a desiccant can become completely saturated if left fully open to the atmosphere for as little as 10 minutes. Who is correct?

A)A only
B)B only
C)Both A and B
D)Neither A nor B

Question 7

The machine that will MOST-Likely remove the refrigerant and recycle it during the vacuum cycle is the:

A)single-pass machine
B)suction service valve
C)compound gauge
D)dual-pass machine

Question 8

All of the following statements about are true EXCEPT:

A)with 70⁰F air entering the evaporator, expect about a 15⁰F drop in air temperature (55⁰F).
B)with 80⁰F air entering the evaporator, expect about a 25⁰F drop in air temperature (55⁰F).
C)with 90⁰F air entering the evaporator, expect about a 30⁰F drop in air temperature (60⁰F).
D)the hardest work a manually controlled air conditioner has to do happens when "normal" is selected.

Question 9

The ____________________ valve is on the output side of the compressor on the high side.

Question 10

The ____________________ valve is on the inlet to the compressor on the low side.

Question 11

What color band will a can of R-1234YF refrigerant have?

A)sky blue
B)red band
C)white
D)orange

Question 12

Which of the following statements is LEAST-Likely true?

A)If there is less than a 2⁰F difference between the outlet and inlet temperatures of the accumulator, the refrigerant coming from the outlet is still liquid.
B)An accumulator system is also called a "dual evaporator" system.
C)A 5⁰F difference between the accumulator inlet and outlet temperatures or frost on the accumulator can indicate two things: either the system is overcharged or the clutch is not cycling.
D)In an expansion valve system, a flooded evaporator is bad.

Question 13

Protect a vacuum pump by changing its oil every ____________________ hours or less.

Question 14

The statement that is MOST-Likely true is:

A)R-134A and R-1234YF have very similar operating characteristics.
B)It is fine if R-134A and R-1234YF refrigerants are mixed as long as there is at least 75 percent of one or the other.
C)R-134A and R12 refrigerant tanks feature the same type of dispensing valve.
D)R-1234YF refrigerant is available in 35-pound containers.

Question 15

The low-pressure gauge is a ____ that reads in either low pressure or vacuum.

A)dual gauge
B)single pass gauge
C)compound gauge
D)suction service valve

Question 16

All of the following statements are true EXCEPT:

A)if mineral oil is mistakenly installed in an R-134A system, it will not lubricate the compressor properly and will separate in the accumulator.
B)moisture causes fewer problems in R-134A systems because it mixes with the PAG oil.
C)moisture control in R-134A is provided by the desiccant in the receiver/dryer or the evaporator.
D)commercial refrigeration units use ester oils, which are hygroscopic.

Question 17

The high-side gauge registers temperature only.

Question 18

Unlike brake fluid, stored refrigerant oil should be sealed tightly by the cap.

Question 19

If a heater has a control valve and it is closed, both hoses should be warm.

Question 20

Air-conditioning systems today have a smaller refrigerant charge than those of the past. A 3-ounce leak represents about 20% of the capacity of a typical system.

Question 21

Before system pressure and duct temperature tests, what items should be met?

Question 22

Why is considered a mistake to allow an air-conditioning system to remain empty?

Question 23

How would you handle a clutch engagement problem?

Question 24

Discuss two reasons why a clutch might fail?

Question 25

What are the rules of thumb when conducting a pressure test?