A/C Installation Written Final Review part 2
A
18-4 low voltage wire is _________________ A. 18-gauge wire with 4 conductors inside B. 18-gauge wire, 4 total allowed in 1/2 inch conduit C. 4 gauge wire with a current rating of 18 amps D. 1.4 gauge wire with a current rating of 4 amps
C
A 1/4 inch service hose will only allow a vacuum pump to pull at ___________ CFC, regardless of the pump's CFM rating. A. 3.0 B. 1.0 C. 0.8 D. 0.25
B
A __________________ can remove any type of foreign matter that enters a refrigeration system A. vacuum pump B. filter drier C. recovery machine D. compressor
B
A __________________ is located in an auxiliary drain pan and is wired in series with the low voltage power supply A. pressure switch B. float switch C. delay timer D. auxiliary thermostat
D
A deep vacuum can most accurately be measured in A. inches of mercury B. inches of water column C. pounds per square inch D. microns
B
A disconnect or shutoff switch should be installed within ____________ feet of each unit and within sight of the unit A. 10 B. 25 C. 20 D. 15
B
A float switch, located in an auxiliary drain pan, is typically wired to A. cycle both the evaporator and condenser fans B. open the low-voltage control circuit C. control a condensate pump D. open the line voltage circuit to the air handler
A
A large refrigeration system that contains a significant amount of moisture should be evacuated with A. a high CFM vacuum pump B. a low CFM vacuum pump C. the system compressor running D. a recovery machine then a nitrogen sweep
B
A service technician is charging and R-410A air-conditioning system that has a TXV metering device. The high-side saturation pressure is 365 psig and the unit's technical manual specifies 10 degrees F of liquid subcooling. What would the desired liquid-line temperature be at the outlet of the condensing unit? A. 10 degrees F B. 100 degrees F C. 110 degrees F D. 120 degrees F
D
A system equipped with a fixed orifice metering device should be charge using the __________________ method A. subcooling B. active C. passive D. superheat
C
A system that is equipped with a ___________________ may require additional steps to ensure that the entire system is evacuated A. TXV B. Relief valve C. solenoid valve D. receiver
True
A system with Schrader valve gauge ports will take longer to evacuate than a system with service valves True or False
A
A system's total refrigerant charge can be found on A. the nameplate of a package-type air-conditioning system B. the nameplate of the outdoor unit of a split-type air conditioning system C. the nameplate of the indoor unit of a split-type air conditioning system D. the nameplate of the outdoor unit of a split-type heat pump system
A
A technician is working on an R-404A refrigeration system and determines that the head pressure is 205 psig and the condenser outlet temperature is 80 degrees F. The technician correctly concludes that the amount of condenser subcooling is A. 10 degrees F B. 20 degrees F C. 80 degrees F D. 90 degrees F
D
A technician is working on an R-404A refrigeration system and determines that the suction pressure is 30 psig and the evaporator outlet temperature is 10 degrees F. The technician correctly concludes that the amount of evaporator superheat is A. -3 degrees F B. 3 degrees F C. 10 degrees F D. 13 degrees F
B
A(n) _____________ leak detector requires a lubricant-specific dye be injected into a charged system to find the leak. A. Halide B. Ultraviolet C. Electronic D. Ultrasonic
C
Acoustical lining for metal ducts is normally made of A. aluminum B. mastic or adhesive C. coated fiberglass D. a flexible rubber or canvas material
A
After installing the refrigerant lines on a split-system, the next step would be to A. pressurize the system with nitrogen for a leak test B. pull the system down into a vacuum C. add or remove refrigerant based on the length of the line set D. open the service valves to allow the stored refrigerant into the system
True
An air conditioner in a climate with average humidity will collect about 3 pints of condensate per hour of operation for each ton of air-conditioning True or False
A
An air conditioner in a climate with average humidity will collect about _____________ of condensate per hour of operation for each ton of air-conditioning A. 1 quart B. 3 gallons C. 9 pints D. 24 gallons
A
An evacuation process that is performed a number of times with nitrogen being used to break the vacuum, and ends with a deep vacuum is known as A. triple evacuation B. refrigerant recovery C. system flush D. nitrogen sweep
D
An oily dust spot on a condenser or evaporator coil could indicate A. a defective fan motor B. noncondensables in the system C. the presence of acid D. a refrigerant leak
C
As a system is charged with vapor refrigerant, the refrigerant tank will likely A. experience a pressure drop and a temperature rise B. experience a pressure rise and temperature rise C. experience a pressure drop and temperature drop D. experience a pressure rise and a temperature drop
B
Atmospheric pressure, 0 psig is the equivalent of about ____________ microns. A. 0 B. 760,000 C. 635,000 D. 100,000
B
Automatic charging capability, auto-stop features, alarms, and wireless remotes are features that are found on some A. digital gauge manifolds B. refrigerant charging scales C. analog gauge manifolds D. analog charging scales
D
Before a full graduated charging cylinder is used to charge a system, it should be A. evacuated to at least 500 microns B. turned upside down for liquid charging C. calibrated based on the vacuum level D. calibrated based on the cylinder pressure
C
Before a newly installed system is started up, it is recommended that A. the factory Schrader pins be replaced with new ones B. the condenser be cleaned with a foaming cleanser C. the crankcase heater be allowed to operate for a specified period of time D. the service valves are returned to their closed position
A
Ductboard duct sections are fabricated from which material? A. Fiberglass B. Plastic C. Sheet metal D. Aluminum
A
Flexible duct used at the end of a metal duct run will A. help reduce noise transmission in the ducts B. greatly reduce airflow and should be avoided C. cause excessive friction losses D. cause the duct to collapse and reduce its inner diameter
A
If the components of a binary refrigerant blend have saturation temperatures of 35 degrees F and 42 degrees F at a pressure of 120 psig, what is the approximate temperature glide associated with this refrigerant A. 7 degrees F B. 35 degrees F C. 42 degrees F D. 77 degrees F
C
If the hot air being discharged from the condenser is recirculated back through the condenser A. the condenser coil will require more frequent cleaning B. the condensing unit will not drain properly C. high head pressure and poor operating efficiency will result D. low suction pressure and higher system capacity will result
D
In order to remove moisture from a refrigeration system using a vacuum pump, it must be in a ________________ state A. solid B. heated C. liquid D. vapor
D
Leaks that occur only when the unit is in operation are called A. combination-dependent leaks B. temperature-dependent leaks C. cumulative microleaks D. vibration-dependent leaks
B
Leaks that require two or more conditions in order to induce leakage are known as A. cumulative microleaks B. combination-dependent leaks C. temperature-dependent leaks D. standing pressure leaks
C
Line sets come in standard lengths of _______________ A. 10 feet and 15 feet B. 15 feet and 35 feet C. 25 feet and 50 feet D. 50 feet and 100 feet
D
Line sets typically come in standard lengths of A. 10 and 20 feet B. 25 and 35 feet C. 15 and 25 feet D. 25 and 50 feet
Contractor furnished, flare fittings and line set, and precharged line set
List the three crafts that are involved in the installation of an air-conditioning system
D
Moisture, acid buildup, and copper plating can be caused by which of the following? A. Refrigerant and oil mixing B. A clogged filter dryer C. An undersized evaporator D. Air in the system
Water Drainage, Solar Influence, and where the best appearance would be
Name at least three criteria for a good location for an air-cooled condensing unit.
D
On a line set used to install a split-system, the __________ line is insulated A. smaller B. compressor discharge C. liquid D. suction
D
On a new package system, the refrigerant charge is A. added in the field, after installation B. very large compared to a split-system C. calculated based the length of the field-installed piping D. added to the system at the factory
A
One of the advantages of a microfoam leak detection solution over standard bubble solutions is that it A. will not pit or corrode the components B. contains chlorides C. can detect leaks as small as 0.1 oz per year D. will react with refrigerant oil and become luminescent
C
Package equipment comes in two different duct connection configurations, A. upflow and downflow B. metal connection and flex connection C. side-by-side and over-and-under D. rooftop connection and sidewall connection
C
Proper evacuation without the use of a gauge manifold requires which of the following? A. Recovery machine B. Nitrogen and a pressure regulator C. Core removal tool D. Electronic leak detector
B
Proper maintenance for a vacuum pump would include which of the following? A. Replacing all of the caps and plugs with new ones B. Changing the oil as often as necessary C. Replacing the oil sight glass D. Installing a new motor on the pump
D
Removing air and/or other noncondensable gases from a system using a vacuum pump is called __________. A. Dehydration B. Evacuation C. Recovery D. Degassing
True
Round metal duct requires more clearance space than square or rectangular True or False
B
Sludge and other solids can be removed from a system by using _______________. A. nitrogen and a trace gas B. liquid-and suction-line filter/driers C. a recovery machine D. vacuum pump and a micron gauge
False
Split-system equipment includes all components in one cabinet or housing True or False
C
Square duct or rectangular duct is assembled with A. mastic and drive clips B. foil tape and mastic C. "S" fasteners and drive clips D. "S" fasteners and zip ties
B
Standing, pressure-dependent, temperature-dependent, vibration-dependent, combination-dependent, and micro are all types of A. charging methods B. leak methods C. evacuation methods D. electronic micron gauges
C
The ___________ is the fitting that connects the duct to the supply register A. plenum B. starting collar C. boot D. takeoff
D
The ______________ provides installation standards, wire sizes, methods of routing wires, and types of enclosures for wiring and disconnects A. National Fire Protection Association (NFPA) B. International Fuel Gas Code (IFGC) C. U.S. Department of Energy (DOE) D. Nation Electrical Code (NEC)
D
The _______________ is both the greatest asset and the greatest liability of an electronic leak detector A. range B. battery life C. cost D. sensitivity
A
The __________________ method should be used to check the charge of a system equipped with a TXV. A. subcooling B. active C. restrictor D. superheat
C
The applied voltage (the voltage that the unit will actually be using) should be withing +/- ___________% of the rated voltage of the unit A. 3 B. 5 C. 10 D. 15
B
The applied voltage (the voltage that unit will actually be drawing) should be within __________% of the rated voltage of the unit A. 3 B. 10 C. 7 D. 5
B
The condenser of a split-system typically contains enough refrigerant for _______ feet of line set A. 10 B. 25 C. 35 D. 50
C
The low-pressure side of the system must not be pressurized to more than ___________ when testing for leaks. A. 75 psig B. 200 psig C. the low-side design pressure D. atmospheric pressure
B
The mechanical strain of motion, rotation, and refrigerant flow are all associated with __________ leaks. A. pressure-dependent B. vibration-dependent C. temperature-dependent D. combination-dependent
D
The most accurate type of gauge for measuring a deep vacuum is a A. compound gauge B. digital manometer C. mercury manometer D. digital micron gauge
C
The most common type of system leaks are ___________ leaks. A. vibration-dependent B. pressure-dependent C. standing D. temperature-dependent
C
The only two substances that should be circulating in a refrigeration system are A. liquid and vapor B. refrigerant and nitrogen C. refrigerant and oil D. nitrogen and oil
False
The process of a solid changing to a vapor without passing through the liquid state is called dehydration. True or False
A
The process of removing both noncondensable gases and water vapor is called __________. A. Evacuation B. Dehydration C. Recovery D. Degassing
C
The service valve position that is used for normal system operation and closes the gauge port is the __________________ position A. mid-seated B. front-seated C. back-seated D. cracked-off-the-back seat
B
The standard wire size for light-duty low-voltage wire is A. 20 gauge B. 18 gauge C. 16 gauge D. 14 gauge
C
The term "blend" refers to a refrigerant that A. has a boiling temperature below 0 degrees F at 0 psig B. has a boiling temperature above 0 degrees F at 0 psig C. is made up of two or more different refrigerants D. has a single saturation temperature at a given pressure
A
To help create an airtight seal between duct sections A. mastic may be applied B. self-tapping sheet metal screws should be used C. duct insulation can be used D. additional duct supports should be installed
A
To perform standing pressure tests and system evacuation, a service valve should be in the _____________ position A. mid-seated B. front-seated C. cracked D. back-seated
A
Two common methods for preventing the vibration of a package system from being transferred to the building or structure are A. rubber and cork pads and spring isolators B. using fiberglass ductboard and flex duct C. canvas connectors and duct insulation D. a roof curb and rigging holes
C
Two types of evacuation methods used by technicians are A. active recovery and passive recovery B. system-dependent and self-contained C. deep vacuum and triple evacuation D. nitrogen sweep and standing pressure test
Package unit combines multiple units into one single unit while split systems divide each system to run as separate units
What are the differences between a package system and a split system?
B
When a deep vacuum is reached (500 microns), the system is valved off and observed for 10 to 15 minutes. A rise in pressure could indicate which of the following? A. It is normal and does not indicate anything B. There may be a leak or the presence of air and/or moisture C. The system charge was not properly recovered prior to evacuation D. There may be acid or sludge in the system
A
When a portion of a refrigerant blend evaporates or condenses before the rest of the same blend, what is occurring? A. Fractionation B. Sublimation C. Pressurization D. Condensation
B
When adding refrigerant to a newly evacuated system, which of the following is the best method? A. Add liquid refrigerant to the system through the suction line service valve B. Add liquid refrigerant to the system through the liquid-line service valve C. Add vapor refrigerant to the system through the suction-line service valve D. Add vapor refrigerant to the system through the liquid-line service valve
B
When calculating the subcooling on a system charged with a zeotropic blend, the ________________ value should be used A. wet bulb B. bubble point C. dew point D. critical point
A
When calculating the superheat on a system charged with a near-azeotropic blend, the _________________ value should be used A. dew point B. wet bulb C. critical point D. bubble point
C
When charging a system with vapor refrigerant, what can be done to increase the pressure in the refrigerant tank? A. Turn the tank upside down B. Heat the tank with an oxyacetylene torch C. Place the tank in a bath of warm water D. Open both the high-side and low-side valves on the gauge manifold
C
When charging an air-conditioning system that is operating with a thermostatic expansion valve, which of the following is used as the primary guideline to ensure that the system is properly charged? A. Evaporator superheat B. System superheat C. Condenser subcooling D. Compressor amperage
B
When checking for a leak in the evaporator coil, the leak detector can be placed A. in the airstream B. in the drain outlet C. in the return D. next to the evaporator fan
B
When connecting round metal duct sections, a minimum of _________ self-taping sheet metal screws should be used. A. 4 B. 3 C. 5 D. 2
D
When connecting sections of round duct A. canvas collars should be used B. flexible connectors are used C. "S" fasteners and drive clips are used D. a minimum of three screws should be used
Condenser subcooling, Evaporator superheat, Condenser and Evaporator saturation temperature, Return Air Temperature (wet bulb and dry bulb), Outside Ambient Temperature
When evaluating the refrigerant charge in a system, what factors would a technician take into account?
False
When hot water is used to raise the pressure of a refrigerant tank, the water temperature should not exceed 120 degrees F True or False
B
When installing the condensing unit of a split-system, it should be A. located out of sight, such as under a deck B. set on a concrete or high-impact plastic pad C. lifted off the ground 24 in. to 48 in. D. located near a municipal water source for cleaning
D
When insulation on the inside of the duct comes loose it can cause A. the system to shut off B. high head pressure C. increased airflow D. reduced airflow
B
When joining two sections of fiberglass ductboard A. "S" fasteners and drive clips are used B. staples and tape are used C. a minimum of three screws should be used D. glue or spot welds are used
B
When leak checking the suction line with an electronic leak detector, the probe should be placed A. near the receiver B. under the pipe insulation C. in the condenser air stream D. in the evaporator ai stream
True
When liquid charging into the vapor line, a restricting valve must be used to vaporize the refrigerant before it reaches the compressor. True or False
A
When refrigerant leaves a storage tank as a liquid and enters the system as a vapor, what process is taking place between the system and the gauge manifold? A. Fractioning B. Restricting C. Gliding D. Condensing
B
When the stem of a king valve is turned completely clockwise, closing the liquid line, it is in the ____________________ position A. mid-seated B. front-seated C. cracked D. back-seated
D
When working with blended refrigerants, the refrigerant must leave the cylinder as a liquid to __________________. A. prevent oil from washing out of the compressor B. ensure that enough refrigerant enters the system being charged C. prevent the refrigerant in the system from entering the refrigerant tank D. prevent fractionation
D
Which of the following conditions requires a system cleanup, an oil test, and oversized filters to be added to the system? A. Noncondensables in the system B. A vibration-dependent leak in the evaporator C. A temperature-dependent leak in the compressor discharge line D. A compressor motor burnout
B
Which of the following statements is true regarding azeotropes and zeotropes? A. They both have no temperature glide B. They are both refrigerant blends C. Neither one experiences fractionation D. They can both be charged as a vapor
A
Which of the following terms would be an example of a refrigerant with no temperature glide? A. A single-compound refrigerant B. A binary refrigerant blend C. A ternary refrigerant blend D. A zeotrope
A
Which of the tools used during the evacuation process can be wireless and use Bluetooth technology? A. Micron gauge B. Vacuum pump C. Core removal tool D. Evacuation hoses
B
______________ installed next to the blower section will help prevent the transmission of noise down the duct A. Duct insulation B. Vibration eliminators C. Threaded rods D. Mastic
