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A refrigerant used in a mechanical refrigeration system should have which of the following characteristics? a) High boiling point b) High freezing point c) Low specific heat d) Low boiling point - ✔✔D For safe storage, the maximum allowable temperature to which refrigerant bottles should be exposed is ______. a) 100°F b) 125°F c) 150°F d) 175°F - ✔✔B Inhalation of high concentrations of CFCs may have which of the following effects? a) drowsiness b) loss of concentration c) cardiac arrhythmia's d) all of the above - ✔✔D Some chlorinated fluorocarbon refrigerants may decompose into a toxic irritating gas if it is ______. a) stored at temperatures below 60 degrees Fahrenheit b) charged into a system having copper fittings c) allowed to mix with compressor oil d) exposed to an open flame or hot surface - ✔✔D
In the presence of an open flame or hot surfaces, chlorinated fluorocarbon refrigerants decomposes and form ______. a) petroleum crystals b) phosgene gas c) water vapor d) carbon monoxide - ✔✔B People familiar with ammonia refrigeration systems become accustomed to its odor and may forget that the vapors ______. a) in a low concentration can cause death b) will dissolve in perspiration and cause caustic burns c) will burn or explode d) all of the above - ✔✔D Ammonia when used as a refrigerant is valuable because of its high efficiency, it is however ______. a) toxic b) flammable c) explosive d) all of the above - ✔✔D The EPA allows a large low pressure system to be pressurized during repairs by ______. a) adding excess refrigerant b) adding nitrogen c) adding heat with controlled hot water d) adding CFC- 22 - ✔✔C In addition to the main outermost scale on the low side compound gage fitted to the portable service manifold, there are often one or more other scales on the face of the gage. These are ______. a) pressure scales for different refrigerants b) pressure scales for varying ambient temperatures
a) Valves 1 and 5 must both be opened to read system pressures on the respective gages. b) Closing valve 1 isolates line #2 from line # c) Closing valve 1 isolates gage #7 from line 2. d) Opening and backseating valve 1 isolates gage #7 from line 2. - ✔✔B The "Tare Weight" of a refrigerant storage cylinder refers to ______? a) the weight of the cylinder with its current contents b) the maximum weight of the refrigerant charge c) the total weight of a fully charged cylinder d) the weight of an empty cylinder - ✔✔D What is the color coding for a storage container of R-134A refrigerant? a) green b) grey c) purple d) light blue - ✔✔D The amount of refrigerant in a storage cylinder is measured by ______. a) pressure b) volume c) weight d) temperature - ✔✔C An untagged refrigerant cylinder is found in your storage area. It is light (sky) blue, and the refrigerant it contains is ______. a) CFC- 12 b) CFC- 11 c) HCFC- 22 d) HFC-134a - ✔✔D
If R-502, which is a mixture comprised of 48.8% R-22 and 51.2% R-115, is recovered from a refrigeration system, it must be placed in a recovery tank containing ______. a) either R-22 or R- 115 b) R-22 only c) R-115 only d) R-502 only - ✔✔D Overfilling a refrigerant container is extremely dangerous because of the high pressures generated. The generation of pressure is the______. a) vapor pressure of the refrigerant b) discharge pressure of the recovery compressor c) hydrostatic pressure of the expanding liquid d) discharge pressure from the recovery cylinder - ✔✔C Refrigerant recovery cylinders are color coded______. a) gray top and yellow lower body b) gray top and light blue lower body c) light blue top and yellow lower body d) yellow top and gray body - ✔✔D Refillable tanks used to ship CFC and HCFC refrigerants or used to recover these refrigerants must meet the standards of ______. a) the United States Coast Guard b) the United States Department of Transportation c) Underwriters Laboratories d) the Enviromental Protection Agency - ✔✔B What is the maximum volume to which refillable refrigeration cylinders should be filled? a) 60% full
