HVACR Journeyman Practice Exam with Answers A+ Graded

HVACR Journeyman Practice Exam with Answers A+ Graded In a (direct expansion) evaporator, liquid refrigerant must boil away as close to the end of the coil as possible in order to: - CORRECT ANSWER-Operate at High Efficiency. What is one of the main reasons that reciprocating compressors are not 100% efficient? - CORRECT ANSWER-Clearance Volume A dirty evaporator and return air filters subsequently causes low evaporator pressures which will cause - CORRECT ANSWER-High Compression Ratios The automatic expansion valve (AEV) maintains a constant ______ in the evaporator. - CORRECT ANSWER-Pressure Short cycling during pump down can be caused by - CORRECT ANSWER-a leaking compressor suction valve. What type metering device is best suited in applications where freeze protection is required? - CORRECT ANSWER-Automatic Expansion Valve (AEV) The "Fan Cycle Control" is used in conjunction with low ambient temperature conditions to control __________. - CORRECT ANSWER-Condenser Pressure What do water cooling towers require? - CORRECT ANSWER-Periodic de-scaling A refrigeration system used to cool another refrigeration system is called a _______. - CORRECT ANSWER-Cascade System High temperature refrigeration applications normally provide box temperatures of: - CORRECT ANSWER-47ºF to 60ºF Why must an oil separator be kept warm? - CORRECT ANSWER-To prevent refrigerant from condensing in the separator during the off cycle. If a pressure control has been adjusted to cut in at 30 psig, in order to have a 10 psig cut out, the differential setting of the control must be: - CORRECT ANSWER-20 Psig Ester based oils are ________. - CORRECT ANSWER-Synthetic Oil What is the minimum clearance for access panels on an outdoor condensing unit? - CORRECT ANSWER-30 inche