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Refrigeration A

Refrigertion Review

QuestionAnswer
Which Which of the following terms represents the form of heat removed from the refrigerant in the condenser of a refrigeration system? Pg1/L22 a. Latent heat of vaporization b. Heat of compression c. Superheat
Dichlorodifluoromethane when vaporized in the presence of an open flame______ pg11/ L22 Phosgene gas.
Moisture in the refrigerant may _____________________.pg 46/ L22 Freeze on the expansion valve seat and reduce the flow of liquid refrigerant
Rigid refrigeration system copper tubing is best cut with a ____? Lesson 2 /pg16 Pipe cutter.
If a refrigeration compressor was short cycling on the low pressure cutout switch, the cause might be that the __________________________? Pg 39/ L22 System was low on refrigerant.
If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be. Pg40 / L22 A shortage of refrigerant.
The high pressure cutout switch will shut down the compressor in a refrigeration system if there is __________________________? Pg 40/L22 Insufficient condenser cooling water flow.
The purpose of a low pressure cutout switch is to _____________________? Pg8 L22 Start and stop the compressor at a preset operating pressure.
The object identified on the illustration as letter “Q” is : Accumulator
The valve indicated by the letter “L” is the: Liquid receiver relief valve.
Which of the following statements concerning the destruction of refrigerant is TRUE? Pg31 L22 Refrigerant can be properly destroyed through incineration.
Some refrigerant vapors are environmentally destructive because_____. Pg 25 / L22 Deplete the atmospheric ozone layer.
When adding refrigerant to the low side of an air conditioning system, it should be added into the _____. Pg 13/L22 Suction service valve as a vapor.
The amount of refrigerant in a storage cylinder is measured by ___. Pg14 L22 Weight.
Ammonia when used as a refrigerant is valuable because of its high efficiency, it is however ______________________________. Pg 19 /L22 a. Toxic b. Flammable c. Explosive
An automatically controlled refrigeration compressor will restart with _____. Pg8 /L22 An increase in the suction pressure.
If the refrigeration compressor crankcase is sweating, the cause may be due to ___. Pg 41/L22 Liquid refrigerant returning to the compressor.
When is it necessary to repair a refrigeration system using R-134-A and the system will be open for more than a few minutes, the open ends of the system should be _______ pg 15/ L22 Plugged.
The low pressure side of a refrigeration system is considered to exist from the ___ pg 1/L22 Expansion valve to the compressor.
The heat exchanger is generally used to_________ pg3 /L22 Heat or cool one fluid by means of another fluid.
The refrigeration system low pressure cutout switch is actuated by_______ pg 8/ L22 Pressure changes in the suction line.
When selecting a lubricating oil in a refrigeration compressor, it must______ Pg9/L22 Have a low pour point.
The valve indicated by the letter “G” is: The thermal expansion valve.
Some chlorinated fluorocarbon refrigerants may decompose into toxic irritating gas if they are ______________________.pg29/L22 Exposed to an open flame or hot surface.
Any person who is experiencing breathing difficulties due to possible exposure to refrigerant vapors ____________________________.pg 19/ L22 Should immediately move or be moved to fresh air.
Zinc rods are installed in the refrigeration system__________ .pg 3/L22 Saltwater condenser.
All persons responsible for the maintenance and repair of air conditioning and refrigeration systems must be certified through an approved Environmental Protection Agency (EPA) program_______________. If they will be performing maintenance, service or repair that could reasonably be expected to release Class 1 or Class 2 refrigerants into the atmosphere.
What must be done to use leak detection methods on a low pressure refrigeration system? Raise the pressure in the system above atmospheric. EPA book
In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the ____________. Pg 1 /L22 Evaporator.
R-12 is generally considered to be a safe, nontoxic, non-flammable and non-explosive refrigerant. It can, however, become highly toxic when_____________. Pg29/L22 In contact with an open flame.
A refrigeration system contaminated with moisture can be affected by _____. pg 15/L22 All of the above.
Thin wall refrigeration system copper tubing is best cut with a _______Lesson 2 pg 16 Tubing cutter.
The low pressure side of a refrigeration system is considered to exist from the ___________. a. Under heavy loads b. During hot gas defrost c. Under light loads d. None of the above.
Refrigeration crankcase sweating is an indication of ___. Pg 41/L22 Liquid refrigerant flooding back.
Refrigerant enters the condenser as a ___________________.pg 1/L22 High pressure vapor.
An oil separator is a device used to remove oil from the _____ pg 10/ L22 Gaseous refrigerant.
The object identified on the illustration as the letter “J” is: The dryer.
The area indicated by the letter “U” is: Hot discharge from the condenser.
Increased levels of UV radiation due to reduction of atmospheric ozone, as caused by the release of certain refrigerant, can affect humans_____. Pg 25/L22 a. By potentially increasing cases of non melanoma skin cancer b. By potentially weakening human immune system c. By potentially increasing the number of cataract cases
Refrigerant that are considered to have no adverse affect on the earth’s stratospheric ozone layer are classified as _______________________.pg 23/ L22 HFC refrigerants.
The presence of gas in the liquid line is undesirable and can be eliminated by _____.pg8/L21 Sub-cooling the liquid.
Liquid line dehydrators are usually in the refrigeration systems in order to ____. Pg 6/L22 Prevent icing of the expansion valve.
Personnel working with refrigeration systems and subject to exposure of refrigerant should wear_______________. Pg 11/ L22 Face shields.
The heat gained per pound of refrigerant in the evaporator is known as the ____pg 5.L 21 Refrigerating heat.
When a relief valve opens on a refrigeration compressor discharge line, it discharges high pressure refrigerant vapor to the ____________________. Pg 7/L22 Suction side of the compressor.
If the suction line between the evaporator and compressor is frosting up, this may be due to the thermal expansion valve if the _____________. Pg 41 /L 22 Thermal bulb coming loose from the suction line.
Foaming of the oil in a refrigeration compressor crankcase is caused by ___. Pg41/L22 Liquid refrigerant flooding the compressor and system.
A low level of refrigerant in the refrigeration system is indicated by____? Pg 42/L22 Bubbles in the sight glass.
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will______________________? Pg 6/ L 22 Decrease the capacity of the coil.
Properties of good refrigerant oil include__________________. Pg 9/ L22 Low pour point
For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is______________________? Pg 29/ L22 130 deg F.
Refrigerant with oil in solution has a ______________________. Pg 9/ L22 Boiling point that will not be affected by entrained oil.
Which of the listed reasons could cause frost to form on the suction line of a refrigeration compressor? Pg 46/ L22 Which of the listed reasons could cause frost to form on the suction line of a refrigeration compressor? Pg 46/ L22
The tool used to expand and “bell” the ends of small diameter copper tubing is a/an? Pg 17/L2 Flaring tool.
The refrigerant gas returning to the compressor should be_____________. Pg 1 / L22 Superheated.
A refrigeration system compressor will have a high suction pressure when_____. Pg 39/L22 The expansion valve being opened too wide.
Adjusting a thermostatic expansion valve involves____________.pg 6/ L22 Suction pressure and coil pressure.
A one ton air conditioning system has which of the listed operating characteristics? Pg9/L21 Its cooling power equals that of melting 2,000 lbs. of ice per day.
The object identified on the illustration as letter “R” is: The evaporator
The substance passing through the valve at letter “M” is: Hot high pressure vapor
Even though the toxicity of most refrigerant is low, precaution must be taken to ___. Pg 12 / L22 a. Prevent the accumulation of high concentration of refrigerant gas within any area b. Thoroughly ventilate any low lying areas where refrigerant may displace air c. Prevent frostbite when tissue is directly contacted by liquid refrigerant
To remove from 33,000 to 35,000 BTU per hour, an air conditioning system should have a minimum capacity of _____________________.pg 9/ L21 3.0 tons.
When checking the oil level in a refrigeration compressor, the most accurate reading is obtained______________. Pg 44/ L22 Immediately after shutdown following a prolonged period of operation.
A properly adjusted thermostatic expansion valve will have a constant valve opening under a condition of constant_____________. Pg 6 / L22 Refrigerant superheat.
The refrigeration system uses a receiver to ___________________. Pg 4/L22 Store liquid refrigerant.
The thermal expansion valve reacts directly to the__________________. Pg 6/L22 Refrigerant gas superheat at the evaporator coil outlet.
Before charging a refrigeration unit, the refrigerant charging lines must be ___. Pg 14/L22 Purged with the refrigerant.
The object identified on the illustration as the letter “E” is : The motor.
The area described by the letter “W” is : The low side
The purpose of the device at letter “Y” is : Sump filling port
Created by: eddangeles