After 1995, supplies of CFC refrigerants will come from
Recovery and recycling
A compound pressure gauge for the low side of the system measures pressure in
psig and inches of mercury (Hg)
A synthetic lubricant presently used with ternary blends containing HCFC's
Alkybenzenes
Ester based oils can be mixed with
No other oils
Chloroflourocarbons (CFC's) and Hydrochloroflourocarbos(HCFC's) have the following similarity
They must be recovered before opening or disposing of an appliance.
To RECOVER refrigerant is to
remove refrigerant in any condition from a system and store it in external container without testing or processing it in any way.
System Dependent recovery devices
captures refrigerant with the aid of the pressure of the gas in the system and/or the compressor of the appliance itself
A refillable cylinder must bot be filled above?
80%
When scrapping a disposable cylinder, the pressure should be reduced at least to:
0 psig
The definition of RECYCLE is:
to clean refrigerant for reuse by oil separation and single or multiple passes through filter-driers.
Refrigerant cylinders should be
All of the above
what is an azeotropic mixture of refrigerants?
the mixture combines and becomes a third refrigerant with its own separate and individual characteristics
Beginning November 14, 1994, the sale of refrigerants and the ability to service and repair refrigeration and air conditioning equipment will be
restricted to persons certified with refrigerant recovery
Under EPA regulations, what standard must reclaimed refrigerant meet before it can be resold?
ARI 700
You have to check a unit which has lost a complete charge. Which gas would cause the least damage to the environment?
dry nitrogen only
A refrigerant label is placed on a
refrigerant cylinder being retired for reclaiming
A refrigerant oil that is hygroscopic
has a high affinity for water
which refrigerant is an HFC
R-134a
which refrigerant is an HCFC
R-22
which refrigerant is a CFC
R-500
which refrigerant contains no chlorine
R-134a
Whenever dry nitrogen is used in service and installation practice, what item is of most importance for SAFETY
That a relief valve is inserted in the line downstream from the regulator
To determine the safe pressure for leak-testing a system, you should use:
low side test pressure indicated on the system data or name plate
Why must cylinders designated "refillable" by the department of transportation be sued for transporting recovered refrigerant?
to meet safety requirements
To work on small appliances after Nov. 14, 1994, technicians must be certified as
Type I, Universal
The size of a vacuum pump and the size of the vacuum hose line will:
determine dehydration time
the system is said to be dehydrated when:
the vacuum gauge shows that you have reached and held the required vacuum as per EPA regulations
A hermetic compressor must never be operated when:
it is under a full vacuum
Cooling occurs in a vapor compression refrigeration system when:
the liquid refrigerant vaporizes
The component of a refrigeration system that changes a low pressure vapor to a high pressure vapor is the
compressor
The component of a refrigeration system that changes a high pressure vapor into a high pressure liquid is the
Condenser
the component of a refrigeration system that controls the amount of refrigerant entering the evaporator is:
metering device
The state and condition of the refrigerant entering the condenser is a:
superheated vapor
The state and condition of the refrigerant leaving the condenser is
subcooled liquid
The state and condition of the refrigerant entering the compressor is
low pressure vapor
Measuring of a refrigeration system vacuum is done
with the system isolated from the pump
Vacuum hose lines should be
both a and c
Refrigerant will migrate to a compressor's crankcase because of a difference in the ____ between the compressor oil and the refrigerant
Vapor pressure
When pressurizing a refrigeration system with nitrogen, you must always
Charge through a pressure regulator
what is the proper method for charging blended refrigerants
charge exact weight of liquid refrigerant into the high side of the system
Technicians receiving a passing grade on this small appliance examination are certified to recover refrigerant during the maintenance, service, or repair of:
PTACs with less than 15 pounds of refrigernt
CFC and HCFC refrigerant can cause suffocation in enclosed areas because:
they are heavier and thus displace the air
refrigerant recovery devices must be equipped with special fittings called
Low loss fittings
Which refrigerant are manufacturers beginning to use a replacement for R-12
R-134a
Effective August 12, 1993, persons using recovery equipment to recover refrigerant from a small appliance must certify to the EPA that they have
Equipment capable of removing 80% of the refrigerant or achieving a 4Hg vacuum whether the compressor is operating or not.
A storage cylinder of recovered R-12 at room temperature of 75 degrees F in the absence of non-condensibles will have a pressure of
75 psig
The following refrigerant used in refrigerators built before 1950 should not be recovered with current recovery devices:
All the above
Failure of a system to hold a vacuum after the evacuation process indicates that:
A leak in the system may exist
When servicing a small appliance for leak repair
it is not mandatory to repair the leak but do so whenever possible
If the EPA regulations change after a technician becomes certified
it is the technicians responsibility to keep up with and comply with any future changes in the law
Which refrigerants can be used for leak detection as a trace gas pressurized with nitrogen.
R-22
Type II certification applies to:
High and very high pressure refrigerants
R-134a is a drop-in replacement for R-12
true
If nitrogen is not available to use with a trace gas to test for a leak, compressed air may be used as a substitute
False
Every refrigerating system shall be protected from high pressure by a:
any of the above
The oils that should be used with HFC-134a refrigeration applications are:
Synthetic esters
The color code for recovery vessels is
gray with a yellow top
Industrial process and commercial refrigeration equipment with an annal leak rate of --- requires repairs under EPA regulations:
35%
At 70 degrees ambient temperature, R-22 will have a saturated vapor of
121.5 psig
what type of refrigerant would you expect to find in a residential air conditioning system
R-22
many larger refrigeration compressors use an open type compressor. Which part of the compressor is likely to leak if the system is shut down for long periods?
rotating shaft seal
which refrigerant requires its own special set of hoses, gauges, vacuum oho, recovery machine, and oil containers.
R-134a
pressure relief valves must never be:
all of the above
system dependent recovery equipment can not be used when
the charge exceeds 15 pounds
the recovery process can be speeded up by:
putting the recovery tank in cold water
Recovery units manufactured before november 15th, 1993 are required to reach recovery levels of ---- on an R-22 appliance if the charge is more than 200 pounds.
4 inches hg
Recovery units manufactured before november 15th, 1993 are required to reach recovery levels of ---- on an R-22 appliance if the charge is less than 200 pounds.
0 inches Hg
The required level of evacuation for recovery equipment manufactured After november 15th, 1993 on a system containing less than 200 pounds of R-12 is
10 inches hg
Recovery units manufactured after november 15, 1993 are required to reach recovery levels of ------ on an appliance using other high pressure refrigerants if the charge is more than 200 pounds
15 inches hg
If a technician's recovery equipment was manufactured before november 15, 1993, he must evacuate a refrigeration system containing 10 pounds of R-500 to
4 inches hg
as defined by ASHRAE standard 15, a sensor and alarm are required for A1 refrigeration to sense
oxygen deprivation
1 mm ov mercury= 0.039 inches of mercury= --- microns
1000
which of the following statements is NOT true of EPA approved recovery equipment manufactured after November 15, 1993
it must be able to handle more than one refrigerant
when evacuating a vapor compression system, the vacuum pump must be capable of pulling a vacuum of ---- microns
500
Boiling point between -50 and +10 Celsius
high pressure appliance
the EPA defines a--- appliance as equipment that uses a refrigerant with a boiling point above 10 degrees C at atmospheric pressure
Low pressure appliance
the evacuation level required by EPA for a low pressure appliance using recovery equipment before November 15 1993 is
15hg
what does 25 mm hg absolute equal
19hg
high pressure chillers using refrigerants R-12, R-22, and R-134a are---- appliances
type II
recovery machines for large chillers usually have water cooled condensers. where would you get this water from when using portable recovery equipment
city water
the evacuation level required by EPA for a low pressure appliance using recovery equipment after November 15 1993 is
25 mm
with type III certification only, you can also work on type I and type II systems
False
the most common refrigerant used by low pressure cholers has been a CFC. The current replacement for R-11 is a HCFC which is:
R-123
The pressure relief device for a low pressure chiller is:
Rupture disc
The rupture disk on a low pressure chiller is connected to the:
evaporator
the rupture disk is generally set for:
15 psig
When leak testing a low pressure chiller, the maximum test pressure should be:
10 psig
A vacuum pump should be capable of pulling a vacuum of at least:
500 microns
Chillers used for comfort cooling with an annual leak rate of --- must be repaired as per the statute
15%
Under EPA regulations, chillers used in commercial refrigeration and or industrial process cooling, with a leak rate of--- must be repaired
35%
Group B1
R-123
Machine room safety standards have been established by
ASHRAE 15
The generally accepted current replacement refrigerant for R-11 which is a CFC is:
HCFC-123
a low pressure chiller using R-11 has been shut down and has an evaporator pressure of 18.1 hg. what is the corresponding temperature
32 deg
Because a low pressure chiller operates in a low vacuum, a constant problem is non-condensibles entering the system. these are drawn into the system through
gaskets and fittings
an automatic purge unit is a small condensing unit which:
All of the above
because air that is vented from a purge unit contains small amount of refrigerant, this can be minimized by:
leak test and repair the chiller
Which o the following repairs would ALWAYS be considered "major" under EPA regulations.
replacement of an evaporator coil
Under EPA regulations, which of the following methods can be used for the purpose of opening a system for non-major repairs?
controlled hot water
refrigerant is added to a centrifugal machine through the:
evaporator charging valve
CFC's will no longer be manufactured in the United States after:
1995
The Montreal Protocol is:
A treaty
an example of a CFC is:
R-12
All devices used for refrigerant recovery must:
meet EPA standards
HFC contains
hydrogen, fluorine, and carbon
it is illegal to vent substitutes for cdc and hcfc refrigerants after:
november 15, 1995
After installing and opening a piercing access valve do not begin recovery procedure if the system pressure is
0
the state of refrigerant leaving the accumulator of a system is
superheated low pressure vapor
Type II classification as defined by EPA, applies to what equipment
air conditioning with over 5 lbs or less
the condition and state of the refrigerant in the condenser is
a mixture of low pressure, high temperature, vapor and liquid