403C Flashcards
What 3 types of eye protection devices can we use?
Full face shields, goggles, safety glasses with side shields.
What is the maximum allowable limit to fill up a refrigerant container?
80%
What is the maximum allowable limit to fill a cylinder with refrigerant that came in contact with oil?
70%
What’s the maximum allowable limit to fill a cylinder with an azeotrope?
60%
What electronic or electric sensor is mounted on the side of the valves on a refrigerant cylinder?
An electronic refrigerant float
Describe how we can use oil color to diagnose issues within the system
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
To what degree are most thermometers to be accurate?
1/10 of a F degree
What is the most comfortable airflow duct temperature?
35 to 46°F
How accurate is an electronic leak detector?
It can be used to find refrigerant leaks as low as half an ounce per year
What colour is not to be used as a method of locating refrigerant leaks?
Read die is not to be used as it clogs the recovery station filters and air conditioning valves
Which is the most accurate method of locating a refrigerant leak?
- 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
What is the purpose of the yellow service hose in the manifold gauge set?
Recover Re-charge Evacuate Add oil and pressure test
Difference between recover and evacuate
Recover is removing refrigerant from the system where as evacuating is to pull a vacuum in the system
What is the mandatory condition of refrigerant hoses to minimize refrigerant loss?
To have a shut off device within 25 cm (10”) of their ends
What are a couple of precautions when installing a manifold gauge set onto the system for checks?
Do not hook up while the system is running and inspect the vehicle before hooking it up
Why do we need the use of a high-capacity vacuum pump?
It helps remove moisture and air out of the refrigerant
What are some exceptions to the use of a high-capacity vacuum pump?
It will not pull moisture out of oil or desiccant
What component do we use to measure a vacuum?
Micron gauge
In order to pull a proper vacuum in the system and remove all moisture what are some conditions that must be met?
System must be operating with a vacuum of 500 µm(microns) for a minimum of 20 minutes and it must hold for five minutes
What is the proper way of crimping a hose in an AC system?
Evenly spaced crimp depressions and pinched ears that are located 7 mm or a quarter inch from the open end of the fittings sleeve
What is the accurate way of describing a hose for AC system use?
Bead lock fitting on a double barrier hose with the bubble style crimping
What is the job of the thermostat?
To open when engine coolant warms to a certain temperature and allow coolant to pass through the radiator to be cooled
When should a properly operating thermostat open?
It should open a temperature that is 3 to 9°F lower then it’s rated temperature
Both hi-lo pressure readings low:
- Low refrigerant charge
- Internal restrictions to refrigerant Flow
- TXV closed
- Temp. Sensitive bulb loosing its charge
When we have low side pressure too high and high side pressure too low:
It could be a faulty compressor or slugged with refrigerant
If both pressure readings are high:
- Azeotrope
- Air flow restrictions
- Overcharged refrigerant
- High pressure switches not working
