Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
126 Cards in this Set
- Front
- Back
|
What are the typical uses of the center port of a gauge set?
|
To vacuum pump, from refrigerant container, to recovery machine inlet
|
|
|
What color are the gauges on a manifold gauge set?
|
blue (low side), red (high side)
|
|
|
What are the typical ranges of pressure measurements used on the gauges of a manifold gauge set?
|
Low side - 30 in. Hg. to 120 PSIG (retard mode goes to 350 PSIG), high side - goes from 0 to 500 PSIG
|
|
|
Is the refrigerant leaving a condenser at a high or low pressure? Is it a liquid or a gas?
|
high pressure, liquid
|
|
|
Is the refrigerant entering the expansion valve (variable metering device) a liquid or gas?
|
liquid
|
|
|
Is the pressure of the refrigerant entering the compressor high or low?
|
low
|
|
|
Where in a refrigerant circuit does a liquid boil to absorb heat?
|
low side evaporator coil
|
|
|
The refrigerant in the suction line is a gas that has been heated above its saturation. What is the condition called?
|
superheated vapor
|
|
|
What can cause liquid refrigerant to migrate to a compressor crankcase?
|
if the compressor is the coldest location in the circuit
|
|
|
List two conditions that can quickly damage a compressor that is starting to run.
|
started (energized) while they are in a deep vacuum, or when their service valves (discharge or suction) are closed
|
|
|
What system failures require taking an oil sample?
|
if the unit has had a leak or major component failure (compressor burnout)
|
|
|
Is flushing with refrigerant an acceptable tube cleaning method?
|
no
|
|
|
In addition to preventing and repairing leaks, what else should a technician do to conserve refrigerant?
|
recover and recycle used refrigerants
|
|
|
What factors affect the speed of an evacuation?
|
size of the equipment, the ambient temperature, the suction line size, and the quantity of moisture in the system
|
|
|
How should gauge set hoses be sized for use in evacuating a system?
|
the hose diameter should be the size of the vacuum pump inlet connection or larger
|
|
|
When evacuating, what is the benefit of using short hoses with large diameters?
|
will dramatically reduce emissions, pressure drop, and evacuation/dehydration time
|
|
|
Which connection determines the preferred size of hose used with a vacuum pump?
|
vacuum pump inlet
|
|
|
As the capacity and suction hose size increase, what happens to the time needed for an evacuation?
|
decreases
|
|
|
What purpose is served by heating a system during dehydration?
|
speeds up the dehydration time
|
|
|
Does a thorough evacuation remove moisture from a system?
|
yes
|
|
|
What can happen to the oil in a compressor if moisture is left in an operating system?
|
can form hydrofluoric and hydrochloric acid
|
|
|
What is the result of over-evacuating a system?
|
no damage will be done
|
|
|
How can a system be leak checked using a low pressure gauge?
|
after the system has been pulled down
|
|
|
How close should a vacuum gauge be connected to the vacuum pump during an evacuation?
|
the vacuum gauge should be connected as far away as possible from the vacuum pump
|
|
|
When measuring the vacuum of a system being evacuated, the system must be isolated. What must be done to the vacuum pump?
|
valve-off
|
|
|
What is ozone?
|
three oxygen atoms
|
|
|
How much ozone can a chlorine atom destroy in the stratosphere?
|
100,000 ozone molecules
|
|
|
What is ozone depletion potential (ODP)?
|
the ability of any chemical to deplete the ozone layer
|
|
|
What is a CFC?
|
chlorofluorocarbon
|
|
|
Which refrigerants are CFC's?
|
CFC-11, 12, 113, and 114
|
|
|
Which chemical in the CFC refrigerants does the most damage to the ozone layer?
|
chlorine
|
|
|
What is an HCFC?
|
hydrochlorofluorocarbons
|
|
|
Which refrigerants are HCFC's?
|
HCFC-22, and HCFC -123
|
|
|
Which is more harmful to the ozone layer, an CFC or an HCFC?
|
CFC
|
|
|
What is it about CFC's that make them more harmful in the stratosphere?
|
a higher ozone depletion potential
|
|
|
What is an HFC?
|
hydrofluorocarbon
|
|
|
Which refrigerant is an HFC?
|
R-134a
|
|
|
What is the ODP of an HFC refrigerant?
|
zero
|
|
|
Which refrigerants contain CHLORINE?
|
CFC's (11, 12, 113, 114) and HCFC's (22, 123)
|
|
|
What refrigerants have high ODP?
|
CFC's
|
|
|
What refrigerants have low ODP?
|
HCFC’s & HFC's
|
|
|
What is an azeotrope refrigerant?
|
a mixture of two or more compounds (refrigerants) where the mixture behaves like a single chemical (new refrigerant)
|
|
|
Is one of the components of R-500 a CFC?
|
yes
|
|
|
Does stratospheric ozone help or hurt the work of the earth's productive shield?
|
Helps
|
|
|
What chemical in the stratosphere tells us ozone depletion is occurring?
|
increased levels of chlorine monoxide
|
|
|
How do we know the chlorine in the stratosphere is coming from CFC's?
|
increases in both chlorine and fluorine have been detected in the stratosphere, the increase in these match the increase in emissions from CFC's
|
|
|
How do we know CFC's get to the stratosphere?
|
high altitude air sampling
|
|
|
What role does the ozone layer play in protecting the earth?
|
filtering out/blocking the harmful ultraviolet radiation (UV-B) emitted from the sun and it helps keep the earth's temperatures stable
|
|
|
What are the effects on health from increased ultraviolet radiation?
|
skin cancer and other radiation related diseases increase, cataracts can more easily occur, immunity against disease is reduced
|
|
|
What are the effects on the environment?
|
timber growth is reduced, crops yields are lowered, marine life and the food chains are impaired, ground level ozone is increased
|
|
|
Is ozone depletion a problem for the United States only or a global problem?
|
Global
|
|
|
What is the Montreal Protocol?
|
first treaty calling for reduction of the available production of CFC's
|
|
|
The Montreal Protocol calls for regulation of what chemicals?
|
CFC's, HCFC's, Halons
|
|
|
On what date was the production and importation of all CFC's phased out?
|
December 31, 1995
|
|
|
Where will we get replacements?
|
recovery and recycling operations
|
|
|
What steps are called for by the Clean Air Act?
|
recovery, recycling, and no venting of refrigerant
|
|
|
What is prohibited by the Clean Air Act?
|
release of CFC and HCFC based materials to the atmosphere
|
|
|
Do state and local laws have priority over federal law? Can they be less strict?
|
no, no
|
|
|
To prevent damage to the ozone layer, the U.S. is making laws to capture the CFC's now in use. What else does the new law do to restrict the release of CFC's?
|
congress gave authority to the EPA to write the regulations
|
|
|
By recovering refrigerants we ensure adequate supplies and prevent venting. What else does the recovery of refrigerants accomplish?
|
Recycling
|
|
|
The Clean Air Act phases out CFC/HCFC production and prohibits venting. What else does it require?
|
recovery of all refrigerants prior to appliance service and disposal
|
|
|
Falsifying or failing to keep required records, failing to reach required evacuation levels and knowingly releasing CFC or HCFC refrigerants, are all violations of the Clean Air Act. What activity with a substitute refrigerant is also a violation?
|
venting
|
|
|
Which refrigerants must be recovered prior to opening a system?
|
all
|
|
|
What releases of a CFC and HCFC are violations of the Clean Air Act?
|
All
|
|
|
On what date was the production and importation of all CFC's phased out?
|
December 31, 1995
|
|
|
Which appliances are covered by Section 608?
|
low and high pressure appliances
|
|
|
What is the primary reason the EPA requires a service aperture or process stub on all appliances?
|
for adding or removing refrigerant from the appliance
|
|
|
Who sets the regulations for recovery machines?
|
EPA
|
|
|
What is a "self-contained" recovery machine?
|
recovery equipment (active) unit has its own compressor (or other transfer mechanism) to pump refrigerant out of the refrigeration system
|
|
|
Is HCFC - 123 a "low" or "high" pressure refrigerant?
|
low
|
|
|
Is CFC - 12 a "low" or "high" pressure refrigerant?
|
high
|
|
|
What is the smallest container in which refrigerants may be sold to Section 608 certified technicians?
|
containers smaller than 20 pounds
|
|
|
What must you do to the refrigerant in an appliance before disposing of the appliance?
|
must ensure that all has been recovered
|
|
|
Who is responsible for removing the refrigerant from household refrigerators prior to disposal?
|
The final person in the disposal chain (scrap metal recycler, landfill owner, etc.)
|
|
|
What is the penalty for violation of the Clean Air Act?
|
up to $27,500 per day per violation and possible loss of technician certification
|
|
|
How much is the bounty for information leading to a conviction?
|
$10,000 if convicted
|
|
|
What can happen if a technician cannot demonstrate an ability to use recovery of recycling equipment?
|
revoking the technician's certification
|
|
|
What is the name of the process that removes refrigerant from a system and stores it without testing or processing?
|
recovery
|
|
|
What is the name for the process that removes moisture and acids from refrigerant but does not test the refrigerant?
|
recycling
|
|
|
What is the name for the process that removes moisture and acids from refrigerant and also chemically tests the refrigerant?
|
reclaiming
|
|
|
What must be done with reclaimed refrigerant before it can be legally resold?
|
level of purity ARI Standard 700
|
|
|
What is the preferred instrument for detecting small leaks?
|
electronic type
|
|
|
What is an inert gas typically used in leak detection?
|
dry nitrogen
|
|
|
What is typically indicated by a dehydrated system failing to hold a vacuum?
|
Leaks in the system
|
|
|
What should be done when recovering the refrigerant from a system where the refrigerant has been improperly mixed?
|
recover to a separate container
|
|
|
Can mixed refrigerants be reclaimed?
|
no
|
|
|
What precautions should be taken when recovering refrigerant from systems with multiple service valves?
|
check for liquid trapped between service valves
|
|
|
What is the effect of low ambient temperature on the time required to complete a recovery of refrigerant?
|
increase the recovery time
|
|
|
Technicians must explain to customers that recovery is necessary and it is required by law. What else should the technician tell the customer?
|
it is necessary to protect human health and the environment
|
|
|
What is different about any leaks in a system charged with a blended refrigerant?
|
blended refrigerants leak from a system at uneven rates
|
|
|
What is "temperature glide"?
|
pressure-verses-temperature curve family of lines
|
|
|
What is a ternary blend?
|
made by combining three different refrigerants
|
|
|
How should systems using a blended refrigerant be charged?
|
a measured charged of liquid into the high side of a system
|
|
|
Is there a "drop-in" refrigerant for CFC - 12?
|
no
|
|
|
How do you leak check an HFC - 134a system with a partial charge (no HFC - 134a detector available)?
|
with pressurized nitrogen
|
|
|
What is the preferred oil to be used with HFC -134a?
|
polyol esters or "ester" based
|
|
|
Can ester based oils be mixed with other oils?
|
no
|
|
|
What does "hygroscopic" mean?
|
readily absorb moisture
|
|
|
What lubricant is recommended for use with a ternary blend?
|
alkyl benzene type
|
|
|
Safety glasses and butyl-lined gloves should be worn for what procedures?
|
recovery or recycling, and handling and refilling refrigerant cylinders
|
|
|
What safety component must be used whenever dry nitrogen is used to pressurize a system?
|
the nitrogen container must be equipped with a pressure regulator
|
|
|
Safety rules for technicians such as; no open flame or hot steam near a refrigerant, never cutting or brazing a charged refrigerant line, and never using oxygen to purge or pressurize lines, are all important. Which one(s) should a technician follow?
|
All
|
|
|
What is a Material Safety Data Sheet?
|
the safety ratings and precautions to be taken for any refrigerant
|
|
|
What safety classification within the ASHRAE standards is the most safe?
|
A1 (no flammability and low toxicity)
|
|
|
What is caused by the inhaling of refrigerant vapor?
|
heart irregularities or asphyxia
|
|
|
What is the major cause of death involving refrigerant?
|
oxygen deprivation
|
|
|
What breathing problem can be caused by CFC -12?
|
asphyxiation (oxygen deprivation)
|
|
|
How can ice be removed from a sight glass?
|
alcohol spray
|
|
|
What must be done with a badly corroded relieve valve?
|
replaced
|
|
|
Where can you find the allowable test pressure on a system?
|
data plate lowest rating
|
|
|
Can oxygen be used to check for leaks? if not, why not?
|
No, explosions may occur
|
|
|
What is the likely result of heating a recovery cylinder with an open flame?
|
the refrigerant in the tank decomposing into a toxic material, venting of refrigerant to the atmosphere, or the tank may explode causing serious injury to people nearby
|
|
|
What is the primary purpose of a disposable cylinder?
|
may only be used for virgin refrigerant from the factory
|
|
|
To what internal pressure should a disposable cylinder be reduced for disposal?
|
0 psi
|
|
|
Should you ever use a disposable cylinder for refrigerant recovery?
|
no
|
|
|
To dispose of a cylinder you should be sure all refrigerant is recovered and the cylinder is no longer usable. What else should you do?
|
the container should be punctured before disposal
|
|
|
For safety, refrigerant cylinders should not be rusted or damaged and always properly color coded. What additional step should also be taken with these cylinders?
|
properly secured at all times
|
|
|
What is the proper color code for recovery cylinders?
|
cylinder - gray, top – yellow
|
|
|
What is the maximum percent by weight that a cylinder may be filled?
|
80%
|
|
|
What can happen if a cylinder is overfilled?
|
could cause rank to rupture with extreme violence
|
|
|
List three methods for measuring the fill level of a recovery cylinder.
|
floats, thermistor type sensors, and weighing scales
|
|
|
How often must reusable cylinders be hydrostatically tested?
|
at least once every five years
|
|
|
Why must only refillable cylinders be used for transport?
|
they are DOT regulated and approved
|
|
|
What must be affixed to a refrigerant cylinder prior to its shipment to a reclaimer?
|
clearly labeled with a DOT classification tag
|
|
|
What is the purpose of a DOT classification tag?
|
must meet the requirements of the Code of Federal Regulation title 49 (type of refrigerant and weight)
|
|
|
What is the correct shipping position for a refrigerant cylinder?
|
vertical and upright position with their valves at the top
|
