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66 Cards in this Set
- Front
- Back
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Technicians maintaining, servicing, repairing or disposing of high pressure or very high-pressure appliances (except small and MVAC), must be certified as (2) -----.
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Type II Technician or a Universal Technician
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After the installation of any type of system, the unit should first be ----- and -----/
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pressurized with nitrogen
leak checked |
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Nitrogen is an ----- gas.
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inert
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In order to determine the general area of a leak, use an (2) -----.
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electronicor ultrasonic leak detector
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Once the general area of the leak is located, the use of ----- will pinpoint the leak.
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soap bubbles
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A refrigeration unit using an open compressor than has not been used in several months is likely to ----- from the -----.
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leak
rotating shaft seal |
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During a visual inspection of any type of system, traces of ----- are an indicator of a refrigerant leak.
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oil
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In addition to the discovery of oil, what else is an indication of a leak in a high-pressure system?
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Excessive superheat, caused by a low refrigerant charge
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EPA regulations require that all comfort cooling appliances containing more than ----- of refrigerant must be repaired when the annual leak rate exceeds -----.
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50 pounds
15% |
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EPA regulations require that all Commercial and Industrial Process Refrigeration containing more than ----- of refrigerant must be repaired when the annual leak rate exceeds -----.
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50 pounds
35% |
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Proper recovery techniques begin with the use of ----- that has been certified by an ----- to meet or exceed -----.
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appropriate recovery equipment
EPA approved laboratory ARI standards |
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Recovered refrigerants may contain (3) -----.
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acids,
moisture, and oil |
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It is necessary to frequently (2) ----- both the (2) ----- on a recycling machine.
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check and change
oil and filter |
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Both recycling and recovery equipment using hermetic compressors have the potential to ----- when drawing a deep vacuum because...
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overheat
the unit relies on the flow of refrigerant through the compressor for cooling |
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Before using a recovery unit, you should always (3) ...
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check the service valve positions, the oil level of the recovery unit, and evacuate and recover any remaining refrigerant from the unit's receiver.
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Technicians working with multiple refrigerants, before recovering and/or recycling a different refrigerant, must purge the recover/recycle equipment by (3)...
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recovering as much of the first refrigerant as possible, change the filter, and evacuate.
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R-134A technicians do not need to comply with the multiple refrigerant recovery rule because...
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the technician must provide a special set of hoses, gauges, vacuum pump, recovery or recovery/recycling machine and oil containers to be used with R-134A only.
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Although recovering refrigerant in the vapor phase will minimize the loss of oil, recovering as much as possible in the liquid phase can...
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reduce recovery time
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The technician may choose to speed up the recovery process by (2) -----.
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packing the recovery cylinder in ice and/or applying heat to the appliance.
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After recovering liquid refrigerant, any remaining vapor is...
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condensed by the recovery system
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When performing refrigerant system service on a unit that has a receiver/storage tanks, refrigerant should be placed -----.
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in the receiver
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Refrigerant should be removed from the condenser outlet if...
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the condenser is below the receiver.
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In a building that has an air-cooled condenser on the roof and an evaporator on the first floor, recovery should begin from...
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the liquid line entering the evaporator.
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After recovery, refrigerant may be returned to the appliance from which it was removed or ----- without being recycled or reclaimed, unless -----
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to another appliance owned by the same person
the appliance is a MVAC like appliance |
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MVAC stands for
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Motor Vehicle Air Conditioner
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The technician should always evacuate an empty recovery cylinder before -----.
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transferring refrigerant to the cylinder.
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(3) ----- should be used (as low loss fittings) to minimize regrigerant release when hoses are connected and disconnected.
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Quick couplers
self-sealing hoses hand valves |
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Refrigerant recovery and/or recyling equipment manufactured after ----- must be (2) by an EPA approved equipment testing organization to meet EPA standards
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November 15, 1993
certified and labeled |
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Required recovery levels for HCFC-22 appliances or isolated components normally containing less than 200 lbs of refrigerant?
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Before or After 11/15/93 0 inches of Hg
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Required recovery levels for HCFC-22 appliances or isolated components normally containing more than 200 lbs of refrigerant?
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Before= 4 inches Hg
After= 10 inches Hg |
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Required recovery levels of other high pressure appliances or isolated components w/less than 200 lbs. of refrigerant
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Before = 4 inches Hg
After = 10 inches Hg |
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Required recovery levels of other high pressure appliances or isolated components w/more than 200 lbs. of refrigerant.
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Before = 4 inches Hg
After = 10 inches Hg |
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Recovery rate leveles of very high pressure appliances.
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Before or After = 0 inches Hg
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After reaching the desired vacuum, the technician should ----- to see if the system pressure rises, indicating that -----
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wait a few minutes
there is still refrigerant in liquid form or in the oil |
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Appliances can be eacuated to atmospheric pressure (0 psig) if -----
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leaks make evacuation to the prescribed level unattainable.
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The technician must ----- a parallel compressor system inorder to recover refrigerant.
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isolate
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Failure to isolate a parallel compressor system will cause an ----- that will prevent refrigerant recovery.
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open equalization connection
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System-dependent recovery equipment cannot be used on appliances containing more than -----
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15 pounds of refrigerant
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Under EPA regulations, a "major repair" means any maintenance, service or repair involving the removal of any or all of the following components (4) -----
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compressor
condenser evaporator auxiliary heat exchanger coil |
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The most common refrigerant used in residential split AC systems used to be -----, but with current changes be sure to -----
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R-22
read the nameplate to determine the type of refrigerant used. |
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The technician must ----- a parallel compressor system inorder to recover refrigerant.
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isolate
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Failure to isolate a parallel compressor system will cause an ----- that will prevent refrigerant recovery.
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open equalization connection
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System-dependent recovery equipment cannot be used on appliances containing more than -----
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15 pounds of refrigerant
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Under EPA regulations, a "major repair" means any maintenance, service or repair involving the removal of any or all of the following components (4) -----
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compressor
condenser evaporator auxiliary heat exchanger coil |
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The most common refrigerant used in residential split AC systems used to be -----, but with current changes be sure to -----
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R-22
read the nameplate to determine the type of refrigerant used. |
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----- will remove moisture from the refrigerant in a system, but there is a limit to their capacity.
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Filter driers
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Some systems are equipped with a moisture indicating -----
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sight glass
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When the sight glass changes color, the system ----- and will need to be -----
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contains excessive moisture
evacuated |
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The filter-drier should be replaced anytime a -----
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system is opened for servicing
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If a strong odor is detected during the recovery process, a ---- may have occured.
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compresser burn-out
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When recovering refrigerant from a system that experienced a compressor burn-out, watch for signs of -----
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contamination in the oil
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A crank case heater is often used to -----
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prevent refrigerant from migrating to the oil during periods of low ambient temperature.
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Refrigerant in the oil will cause ----- in the ----- at start up.
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oil foaming
compressor |
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When evacuating a vapor compression system, the vacuum pump should be capable of pulling ----- of vacuum.
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500 microns (29.90 inches Hg)
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The more accurate and preferred method of measuring a deep vacuum is -----
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in microns
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A hermetic compressor's motor winding could be damaged if -----
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energized when under a deep vacuum
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the use of a large vacuum pump could cause trapped water to -----
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freeze
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During evacuation of systems with large amounts of water, it may be necessary to ----- by -----.to -----
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increase pressure
introducing nitrogen counteract freezing |
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The source of most non-condensables is -----
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air
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Non-condensables will cause -----
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higher discharge pressures.
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Where there is a risk of freezing, liquid charging of an R-12 refrigeration system should begin with -----, followed by -----.
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vapor from a vacuum level to a pressure of apx 33 psig
a liquid charge through the liquid-line service valve |
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When you are to charge a system that contains a large quantity of refrigerant, the proper method is to ----.
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follow the same procedure as when you have a risk of freezing during an R-12 liquid charge
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ASHRAE standard 15 requires a refrigerant sensor that will ----- and ------ in occupied equipment rooms where refrigerant from a leak will concentrate
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sound an alarm
automatically start a ventilation system |
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Refrigerants (3) ----- are categorized as A-1
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CFC-12, CFC-11, and HFC-134a
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All refrigeration systems must be protected by a ----- and -----.
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pressure relief valve(s)
must not be installed in series |
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Never energize a reciprocating compressor if the discharge service valve is -----.
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closed
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