403C

Question 1

What 3 types of eye protection devices can we use?

Answer 1

Full face shields, goggles, safety glasses with side shields.

Question 2

What is the maximum allowable limit to fill up a refrigerant container?

Answer 2

80%

Question 3

What is the maximum allowable limit to fill a cylinder with refrigerant that came in contact with oil?

Answer 3

70%

Question 4

What’s the maximum allowable limit to fill a cylinder with an azeotrope?

Answer 4

60%

Question 5

What electronic or electric sensor is mounted on the side of the valves on a refrigerant cylinder?

Answer 5

An electronic refrigerant float

Question 6

Describe how we can use oil color to diagnose issues within the system

Answer 6

Brown oil would represent moisture in the system; gray oil would represent metal in the system and black oil shows signs of aeration in the system

Question 7

To what degree are most thermometers to be accurate?

Answer 7

1/10 of a F degree

Question 8

What is the most comfortable airflow duct temperature?

Answer 8

35 to 46°F

Question 9

How accurate is an electronic leak detector?

Answer 9

It can be used to find refrigerant leaks as low as half an ounce per year

Question 10

What colour is not to be used as a method of locating refrigerant leaks?

Answer 10

Read die is not to be used as it clogs the recovery station filters and air conditioning valves

Question 11

Which is the most accurate method of locating a refrigerant leak?

Answer 11

• Pressurized nitrogen at 150 psi minimum max 250psi
• use soap and water to look for bubbles in the airlines and watch for pressure drops as little as one psi over five minutes

Question 12

What is the purpose of the yellow service hose in the manifold gauge set?

Answer 12

Recover
Re-charge 
Evacuate 
Add oil 
and pressure test

Question 13

Difference between recover and evacuate

Answer 13

Recover is removing refrigerant from the system where as evacuating is to pull a vacuum in the system

Question 14

What is the mandatory condition of refrigerant hoses to minimize refrigerant loss?

Answer 14

To have a shut off device within 25 cm (10”) of their ends

Question 15

What are a couple of precautions when installing a manifold gauge set onto the system for checks?

Answer 15

Do not hook up while the system is running and inspect the vehicle before hooking it up

Question 16

Why do we need the use of a high-capacity vacuum pump?

Answer 16

It helps remove moisture and air out of the refrigerant

Question 17

What are some exceptions to the use of a high-capacity vacuum pump?

Answer 17

It will not pull moisture out of oil or desiccant

Question 18

What component do we use to measure a vacuum?

Answer 18

Micron gauge

Question 19

In order to pull a proper vacuum in the system and remove all moisture what are some conditions that must be met?

Answer 19

System must be operating with a vacuum of 500 µm(microns) for a minimum of 20 minutes and it must hold for five minutes

Question 20

What is the proper way of crimping a hose in an AC system?

Answer 20

Evenly spaced crimp depressions and pinched ears that are located 7 mm or a quarter inch from the open end of the fittings sleeve

Question 21

What is the accurate way of describing a hose for AC system use?

Answer 21

Bead lock fitting on a double barrier hose with the bubble style crimping

Question 22

What is the job of the thermostat?

Answer 22

To open when engine coolant warms to a certain temperature and allow coolant to pass through the radiator to be cooled

Question 23

When should a properly operating thermostat open?

Answer 23

It should open a temperature that is 3 to 9°F lower then it’s rated temperature

Question 24

Both hi-lo pressure readings low:

Answer 24

• Low refrigerant charge
• Internal restrictions to refrigerant Flow
• TXV closed
• Temp. Sensitive bulb loosing its charge

Question 25

When we have low side pressure too high and high side pressure too low:

Answer 25

It could be a faulty compressor or slugged with refrigerant

Question 26

If both pressure readings are high:

Answer 26

• Azeotrope
• Air flow restrictions
• Overcharged refrigerant
• High pressure switches not working