A/C service and Refrigeration
PSIG and inches of mercury
A compound pressure gauge for the low side of a system measures pressure in ?
at the evaporator outlet.
The correct location for a TEV sensing bulb is __________.
20
The exhaust from a refrigeration equipment room shall not be less than _____ feet from a property line or opening into a building.
in systems to obtain better system performance and higher efficiency.
What type of equipment would use a TXV ?
A reciprocating compressor larger than 5 HP.
What type of oil pump requires an oil safety control ?
Small reciprocating compressors
What type of refrigeration system uses splash oil lubrication ?
50
When an air conditioning system is not in operation, the accumulator should have an adequate liquid holding capacity of not less than _______ % for the entire system.
sight glass
A __________ is not a method presently used for checking the fill level in a recovery tank.
capillary tube
A ___________ has no sensing bulb.
Accumulator
A ___________ prevents liquid from flooding back to the compressor.
Evaporator
A _______________ is the part of the system in which liquid refrigerant is vaporized to produce refrigeration.
oil separator
A _______________ separates the oil from the hot compressed vapor by using a tank or cylinder with a series of baffles or screens collecting oil which drops to the bottom of the separator and is returned to a compressor's crankcase.
metering device
A _____________________ is a refrigeration system control that converts high pressure, high temperature liquid refrigerant to a low temperature, low pressure mix of liquid and vapor refrigerant.
Reciprocating
A compressor with a piston that travels back and forth in a cylinder is a _______________ compressor.
Condenser
A heat exchanger designed to liquify refrigerant vapor by the removal of heat is a _______________.
Subcooling
A liquid existing at a temperature below its normal boiling point is known as _______________.
in the DX evaporator the refrigerant is converted to vapor in the evaporator whereas it remains liquid form in the flooded evaporator.
A significant difference between a DX evaporator and a flooded evaporator is ______________.
turns the compressor off at a set pressure and when the pressure in the evaporator rises the system turns back on.
A system with a primary low-pressure switch _______________.
oxygen deprivation
According to ASHRAE Standard 15 a sensor and alarm are required for type A-1 refrigerants to sense ___________.
A1
According to ASHRAE refrigerant safety classification standard which designation would be the safest ?
new refrigerant
After a leak in a system using a zoetrope refrigerant is repaired and the system has been evacuated the system should be charged with ?
the system to work harder due to increase in condensing temperature.
Air in a refrigeration system mainly causes ____________.
Copper, Brass, and Bronze
Ammonia is corrosive to ______________.
ASHRAE-15
Ammonia refrigerating systems shall comply with _____________.
electrical current
An ampere measures the flow of ___________.
2
Annealed copper tubing shall not be used in nominal sizes larger than ______ inches.
Superheat
Any temperature of a gas above the boiling point for that liquid or the excess temperature of a vapor above its temperature of saturation is known as ___________________.
yellow tops and gray bodies
Approved refrigerant recovery cylinders can be identified by which color code ?
hydrochloric and hydrofluoric acid or, phosgene gas.
At high temperatures R-12 and R-22 can decompose to form _____________.
1000
Brazing temperature should be _________ degrees F.
Receiver, sight glass, moisture indicator and, filter dryer.
Components most often found in the refrigeration system liquid line are a _____________.
number of cylinders of each gas
Dot regulations 49 CFR requires that the ___________ be recorded on the shipping paper for a hazard class 2.2 non flammable compressed gas.
Refrigerant recycling rule
Effective July 1, 1992 Section 608 of the _____________ prohibits individuals from intentionally venting ozone-depleting substances used as refrigerants.
pitch towards the compressor.
Horizontal piping runs used in a refrigeration system should _____________.
flash-gas
In refrigeration, ________________ is refrigerant in a gas form produced spontaneously when the condensed liquid is subjected to boiling.
1
NEMA states that a three-phase motor should operate successfully under running conditions at rated load when the voltage imbalance does not exceed _____ %
discharge line.
Oil separators are located close to the compressor in the ________________.
phosgene gas
Open flame that comes in direct contact with R-22 creates _____________.
5
Operating a three-phase electrical motor at a phase imbalance above _________ % will most likely damage the motor.
circuit resistance to increase and impede weld (reduce) current flow across the connection.
Poor electrical contact can cause ________________.
processed so that it meets the standard for new refrigerant.
Reclamation of a refrigerant means that it is ______________.
saturated or sub-cooled high-pressure liquid
Refrigerant entering the Thermal Expansion Device of an R-22 heat pump is ___________.
systems owned by the same person
Refrigerant recovered or recycled can be returned to the same system or ___________ without restriction.
recycling.
Refrigerant that is cleaned using oil separation and single or multiple passes through devices, such as replaceable core filter-driers, which reduce moisture, acidity, and particulate matter is ___________________.
recovered
Refrigerants removed from a system in any condition without necessarily testing or processing is ______________.
reclaimed
Refrigerants reprocessed to the same specifications as for new refrigerants by means including distillation is known as ______________.
130
Refrigeration oil must be heated up to ________ degrees F before removing it from a system to minimize refrigerant release.
15
Refrigeration systems in all sectors except for commercial and industrial process refrigeration sectors are required to repair leaks that would release ______ % or more of the charge over a year within 30 days of discovery.
30/35
Refrigeration systems in commercial and industrial process refrigeration sectors are required to repair leaks within ______ days when the equipment leaks at a rate that would release ______ % or more of the charge over a year.
a condenser or, an evaporator
Replacement of ________________ is a repair which would always be considered major under EPA's regulations.
low-loss fittings
Section 608 does not consider small releases of refrigerant resulting from the disconnection of hoses however, effective November 15, 1993 recovery and recycling equipment must be equipped with ________.
the charge is more than 15 pounds
System dependent recovery equipment cannot be used when ______________.
80/90
Technicians repairing small appliances such as house hold refrigerators, window air conditioners, or water coolers must recover ________ % of the refrigerant when the compressor is not operational and _______ % when the compressor is operational.
Type II
The EPA _______ certification is for servicing and disposing of high or very high-pressure appliances except small appliances and MVAC's.
Type III
The EPA _______ certification is for servicing or disposing of low-pressure appliances.
Type I
The EPA ________ certification is for servicing small appliances (household refrigerator, window A/C)
geothermal system
The best method to evaluate proper operation of a _______________ is to verify the water flow rate is correct by measuring pressure drop through the heat exchanger, using P/T plugs and, taking the difference from the input temperature and the outlet temperature. Checking the heat of extraction (water side capacity in heating) and heat of rejection (water side capacity in cooling) by using superheat and subcooling measurements.
Accumulator
The component directly following the evaporator of refrigerant in a system is ?
Condenser
The component of a refrigeration system which converts a high-pressure vapor to high-pressure liquid is a ____________.
80
The liquid receiver stores refrigerant when the system is operating at less than maximum heat load and is generally designed so that receiver can hold all of the system charges and still be no more than _______ % full.
micron gauge
The most accurate way to measure a vacuum is with a ___________.
High-side pressure
The parts of a refrigerating system subject to condenser pressure is ______________
Low-side pressure
The parts of a refrigerating system subject to evaporator pressure is ______________
flash-gas
The presence of ___________ in the liquid lines reduces the efficiency of the refrigeration cycle, leads several expansion systems to work improperly and, increases superheating in vapor.
boil off or, vaporize
The principle of evacuating a system using a vacuum pump is to lower the system pressure so any moisture can ________________.
Crankcase heater
The purpose of a _______________ is to prevent refrigerant from migrating back to the compressor during the off cycle.
it keeps the metal clean once soil has been removed.
The purpose of flux used in soldering is ____________.
a low pressure vapor.
The state of refrigerant entering the compressor of a refrigeration system is ?
refrigerant liquid at the expansion device
The sub-cooling charging method gives an introduction to the amount of __________.
14.7
To translate PSIG to PSIA when using a temperature-pressure-chart, _______ must be added.
ARI 700
Under EPA's regulations, what standard must reclaimed refrigerant meet before it can be resold ?
34
What ASHRAE standard is for safety classification for refrigerants ?
A discharge port being opened too much, a reciprocating compressor with bad valves and, bad compression.
What causes the needles on A/C service gauges to flutter when connected to a running system ?
B1
What classification is R-123 ?
B2
What classification is R-717 ?
CFC
What compound has the highest ozone depletion potential (ODP) ?
Larger semi-hermetic compressors and, compressors that have positive oil pumps.
What compressor types require an oil alarm ?
If the pressure drop in the evaporator coil exceeds 3psi and, the coil has a distributor tube.
What determines if a system requires an externally equalized TXV ?
corrosion of metal parts
What does humidity cause if formed inside a compressor ?
Chlorine
What elements in refrigerants cause ozone depletion ?
Dichloro-trifluoroethane
What is R-123 also known as ?
tetrafluoroethene
What is R-134a also known as ?
Water
What is R-718 also known as ?
500
What is the micron level to which a system should be evacuated down to ?
fractionation
What is the process called when each of the refrigerants used in a blended refrigerant leak at a different rate if released into the atmosphere changing the proportions of the refrigerants used in the blend ?
A1
What refrigerant classification is R-134A ?
liquid or, discharge line
What side of a refrigeration system experiences hot flash which then returns to liquid ?
liquid refrigerant
When charging a system that uses a zoetrope refrigerant the system should be charged with ?
only charge with nitrogen vapor and use a regulator.
When charging a system with nitrogen ______________.
both liquid and vapor refrigerant
When charging refrigerant by weight you can charge with _____________.
check the moisture and acid content of the system
When determining the type of burnout in a system with a hermetic compressor the first thing you would do is ?
cause trapped water to freeze.
When evacuating a system, the use of a large vacuum pump could ____________.
traces of oil
When first inspecting a hermetic system known to be leaking you should first look for ?
Attach DOT classification tags
When transporting cylinders containing used refrigerant, DOT requires that you ?
motor winding could be damaged if energized.
When under a deep vacuum a hermetic refrigeration's compressor ____________.
electronic leak detector
Which leak detection method is most effective for locating the general area of the small leak ?
wearing a respirator
Which of the following is not a standard recommended safe work practice when recovering refrigerants ?
for different altitudes and, types of refrigerant.
Why are expansion valves adjustable ?
latent heat
__________ is the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without change of temperature.
azeotrope
______________ is a mixture of two liquids which has a constant boiling point and composition throughout distillation.