Deck 36: Heating and Air Conditioning Service

Question 1

9)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

Answer 1

C

Question 2

6)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

Answer 2

C

Question 3

10)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.

Answer 3

D

Question 4

2)The high-side gauge registers temperature only.

Question 5

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

Question 6

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

Question 7

13)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

15)The statement that is MOST-Likely true is:

A) R-134A has a 10-30 psi increase on the high side and it is 6⁰-7⁰ warmer.
B) the low side pressure with R-134A is typically 3 pounds more than with R-12.
C) R-134A is about 15% more efficient than R-12.
D) R-134A requires less weight of refrigerant during a refill because R-134A is a different density.

Question 9

14)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 10

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

Question 11

11)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

Question 12

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

Question 13

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

Question 14

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

Question 15

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

Question 16

7)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 17

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

Question 18

3)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 19

12)The required time for factory evacuations is only about ____ seconds, which is extremely fast compared to service in the aftermarket.

A) 20
B) 45
C) 55
D) 60

Question 20

8)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 21

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

Question 22

25)Discuss two reasons why a clutch might fail?

Question 23

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

Question 24

24)How would you handle a clutch engagement problem?

Question 25

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