Advanced Refrigeration: Units 25 and 26: Refrigeration and Air Conditioning Technology (PCI-RH)

What special precautions should be taken with drain lines in walk-in coolers? Select one: a. All of the above b. Trapped to prevent air from being pulled in. c. Freeze protection d. sloped downward

All of the above

The _____________ valve is a straight through valve with little pressure drop. This valve can be soldered into the line, but temperature needs to be considered. Select one: a. Compressor service b. refrigeration line service c. diaphragm d. ball valve

Ball valve

Large or small compressors on parallel compressor racks, which are usually dedicated to the coldest cases, are called; Select one: a. both A and C b. booster compressors c. satellite compressors d. remote compressors

Both a and c

Parallel compressors often referred to as a rack system may use; Select one: a. a common accumulator, but never a common reciever. b. a common suction, but not a common discharge header. c. both common suction header and common discharge header. d. a common discharge header, but not a common suction header.

Both common suction header and common discharge header

Multiple compressors provide: Select one: a. capacity control b. lower humidity in high humidity locations c. positive oil return d. zone control

Capacity control

What valve is used to control excessive pressure entering the compressor during hot pull down? Select one: a. Oil pressure regulator b. Crankcase pressure regulator (CPR) c. Evaporator pressure regulator (EPR) d. Head pressure regulator

Crankcase Pressure Regulator

When one large compressor is used, what desirable feature should it have? Select one: a. Cylinder unloaders or variable speed drive b. Hot gas bypass c. Discharge muffler d. Suction muffler

Cylinder unloaded or variable speed drive

The oil separator is installed in the: Select one: a. liquid line b. hot gas bypass line. c. suction line d. discharge line

Discharge line

The suction line accumulator prevents flood back from which of the following: Select one: a. An evaporator fan set to high b. Flooding after hot gas termination c. An undercharge of refrigerant d. TXV bulb clamped too tight to the suction line.

Flooding after hot gas termination

The " Low Ambient Control" is used to control; Select one: a. compressor b. evaporator fans c. head pressure d. suction pressure

Head pressure

What is the special valve used in a refrigerated air drier? Select one: a. Three way valve b. Hot gas bypass valve c. Four way valve d. Defrost valve

Hot gas bypass valve

When the compressors are located in the equipment room, the piping is routed Select one: a. in the back of the walls. b. in suspended ceilings. c. between the walls. d. in floor chases or in plastic pipes under the floor.

In floor chases or in plastic pipe under the floor

An evaporator pressure regulator valve (EPR valve) is a mechanical control that; Select one: a. limits pressure set point in the evaporator. b. controls compressor cycling c. is used with a capillary tube system to prevent high suction pressure. d. limits the pressure and set point of a thermostatic expansion valve.

Limits pressure set point in theevaporator

The _______________ switch can be used for low charge protection and as a thermostat. Select one: a. overload b. low pressure c. high pressure d. oil safety

Low pressure

The _____________ control maintains the correct operating head pressure on air cooled equipment in both mild and cold weather by cycling the condenser fan. Select one: a. low pressure b. high pressure c. modulating d. low ambient

Low-ambient

The oil return orifice inside a suction line accumulator is designed to: Select one: a. equalize discharge and suction pressures during off cycle. b. meter liquid refrigerant and oil at an acceptable rate c. return oil only during the off cycle back to the compressor. d. maintain the same pressure in the evaporator to the inlet of the compressor.

Meter liquid refrigerant and oil at an acceptable rate

Which is not a method of low-ambient control on air cooled equipment? Select one: a. Fan speed control b. Fan cycle controls c. Flooding a condenser d. Modulating TXV

Modulating TXV

What type of defrost is normally used for vending machine medium temperature applications? Select one: a. none of the above b. off cycle c. electric d. hot gas

Off cycle

Vibration eliminators should be installed __________ to the compressor crankshaft centerline. Select one: a. perpendicular b. vertical c. at a 90 degree angle d. parallel

Perpendicular

The purpose of the crankcase pressure-regulating valve is to: Select one: a. maintain constant pressure in the crankcase. b. maintain constant pressure in the evaporator. c. prevent a compressor overload condition. d. prevent a compressor from going into a vacuum.

Prevent a compressor overload condition

The function of the evaporator pressure regulator is to: Select one: a. prevent a maximum pressure in the evaporator. b. prevent a minimum pressure in the evaporator. c. maintain a constant evaporator temperature. d. maintain a constant evaporator pressure.

Prevent a minimum pressure in the evaporator

An oil separator must be kept warm in order to: Select one: a. prevent refrigerant from condensing in the separator during the off cycle. b. keep the oil at the same temperature as the oil in the crankcase c. prevent sluggish return of the oil to the crankcase. d. operate properly when exposed to low outdoor temperatures

Prevent sluggish return of the oil to the crankcase

The crankcase heater is used to prevent: Select one: a. high compressor superheat under low ambient conditions. b. prevent liquid flood back to the compressor. c. refrigerant migration to the compressor crankcase during the off cycle. d. refrigerant migration to the compressor crankcase during the on cycle.

Refrigerant migration to the compressor crankcase during the off cycle

Which is not a basic component of the compression refrigeration cycle? Select one: a. Suction filter b. Evaporator c. Condenser d. Compressor

Suction filter

Crankcase heat is required for many refrigeration systems, especially R-22 systems because of refrigerant migration during downtime. Select one: True False

True

Defrost with internal heat can be accomplished with hot gas from the compressor. Select one: True False

True

The primary advantage to parallel compressor systems is their ability to nearly exactly match the refrigeration load, often referred to as "load matching" Select one: True False

True

Two types of defrosts used with low temperature fixtures are hot gas and electric defrost. Select one: True False

True

Vibration Eliminators are recommended to be installed close to the compressor and routed in the same direction as the compressor crankshaft. Select one: True False

True

Capacity control of a large compressor can be performed with; Select one: a. hand valves b. dampers c. solenoid valves d. unloaders

Unloaders