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Hvac > EPA 608-2019 > Flashcards

EPA 608-2019 Flashcards

1
Q

The recovery procedure should not be started , if the system pressure is ……….. after installing or opening a piercing access value.

A

Zero psig

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2
Q

CFC means

A

Chloroflourocarbons

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3
Q

1st Highest ODP ( Ozone depletion potential)

A

CFC cloroflourocarbins

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4
Q

HCFC means

A

Hydrochlorofluorocarbone

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5
Q

2nd highest ODP

A

Hydrochlorofluorocarbone (HCFC)

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6
Q

If a refrigerant has no chlorine, what potential it doesn’t cause and what does it still do.

A

Doesnt cause ODP ( Ozone depletion potential) but still GWP (Global Warming Potential)

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7
Q

Ozone can be destroyed by ____ and _____ atoms emitted into the atmosphere

A

chlorine and bromine

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8
Q

GWP means

A

Global warming potential

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9
Q

GWP main contributor in refrigerant is

A

Fluorine

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10
Q

One chlorine atom can destroy _________ 03 molecules

A

100,000

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11
Q

Refrigerants can only be sold to section 608 certified technicians true or false

A

True

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12
Q

Technicians must be 606 certified before handling refrigerant true or false

A

False (its 608 certified)

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13
Q

Which organization approves recovery systems is certified

A

EPA

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14
Q

Systems of 50 lb or more of refrigerant are subject to leak repair requirements

T or F

A

True

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15
Q

which person in the disposal chain is responsible to dispose of or recover refrigerants

A

The last person

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16
Q

Reclamation requires testing to ARI 700 or 800 purity standards before being resold

A

ARI 700

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17
Q

are required levels must be followed during recovery and pump down equipment?

A

Yes

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18
Q

GWP main contributor in refrigerant is ______

A

Florine

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19
Q

is an international agreement for the phase out of CFC and HCFC refrigerants

A

Montreal protocol of 1987

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20
Q

is an international agreement to reduce greenhouse gas emissions

A

Kyote protocol 1992 United nations agreement

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21
Q

SNAP means

A

is the significant new alternative policy program

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22
Q

Recover means

A

to take refrigerant from a system and put it into a recovery bottle

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23
Q

Recycle means

A

to partially clean a refrigerant by running it through multiple filter driers for reuse

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24
Q

Reclaim means

A

To clean a refrigerant and bring it back to ARI 700 standards of purity for resale or reuse

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25
Q

Which blends causes no ODP?

A

HFC (Hydrofluorocarbon) & HC (hydrocarbon)

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26
Q

What’s the the difference of HFC (hydrofluorocarbon) and HFO (hydrofluoroolefin)

A

Differs from HFC due to double bond

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27
Q

Which blend is the only one that cause low GWP?

A

HFO (hydrofluoroolefin)

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28
Q

(EPA) means

A

United States Environmental Protection Agency

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29
Q

What evidence do we have that CFCs and HCFCs are depleting the ozone?

A

The rise in the amount of chlorine measured in the stratosphere over the past two decades
matches the rise in CFC emissions over the same period.

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30
Q

What is the purpose of the CAA?

A

To limit how much of a pollutant can be in the air anywhere in the US.

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31
Q

What three things is the CAA doing to

control chlorofluorocarbon emissions?

A
  1. Phase-out:
    Set dates to phase out CFCs and HCFCs.
  2. Prohibit venting:
    Prohibit venting of CFC and HCFC refrigerants and their substitutes.
  3. Disposal requirements:
    Require the EPA to set standards for recovery of refrigerants prior to appliance disposal.
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32
Q

What can states do in addition to the CAA?

A

The state laws must comply with the CAA and in some cases are as strict or stricter than the CAA laws.

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33
Q

What three things can happen if you violate the CAA?

A
  1. Up to $27,500 per day, per violation
  2. Losing one’s certification to handle refrigerants
  3. Appearing in US Federal Court for the charges
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34
Q

What incentive do others have to

turn you in for violating the CAA?

A

An award of up to $10,000 is offered by the EPA to those individuals who supply information leading to a penalty against a technician that intentionally vents.

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35
Q

Who can purchase refrigerants and what size cylinders can be purchased?

A

Only certified technicians may purchase refrigerants. The smallest cylinder a 608-certified technician may purchase is 20 pounds. Only a 609-certified technician (automotive) may purchase smaller containers.

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36
Q

What is the Montreal Protocol?

A

The Montreal Protocol on Substances That Deplete the Ozone Layer is a treaty among nations designed to protect the stratospheric ozone layer.

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37
Q

When was the CFC phase-out date?

A

December 31, 1995

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38
Q

Where do CFC refrigerants come from for equipment servicing of older systems?

A

recovery and recycling

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39
Q

Is it allowed to release nitrogen into the atmosphere? How about a mixture of nitrogen and refrigerant?

A

Yes you can release nitrogen into the atmosphere, but you may NOT release a mixture of nitrogen and refrigerant.

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40
Q

What must be done before scrapping a refrigerant container?

A

All CFCs and HCFCs must be recovered before disposing of appliances or containers.

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41
Q

Who is responsible for removing refrigerants from a system that is being disposed of?

A

The final technician or person in the disposal chain.

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42
Q

Are there “drop-in” replacements for R-12 systems? Why or why not?

A

There is no “drop-in” replacement gas for R-12 systems. All replacement refrigerants require additional retrofit procedures. In particular, the new refrigerants are incompatible with the oils and lubricants used in R-12 systems and therefore, oils must be checked and changed out as part of the retrofit procedure.

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43
Q

What type of oil is used in R-134a and what oils will it mix with?

A

Ester based oils - do not mix with other oils

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44
Q

What type of lubricant is used with HCFCs?

A

Ternary blends are used with a synthetic alkylbenzene lubricant. Alkylbenzene lubricant is hygroscopic, meaning that it absorbs (takes on) moisture.

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45
Q

What is the trait of a hygroscopic lubricant?

A

It abosorbs moisture

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46
Q

What is temperature glide and which type of blend won’t have it?

A

The difference in temperature which occurs when a refrigerant evaporates or condenses under constant pressure.

azeotropic refrigerant do not exhibit
temperature glide

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47
Q

Will the gases in a ternary blend leak at the same rate? Why or why not?

A

No, because they have different vapor pressures.

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48
Q

How does refrigerant change states through each of the four major components of the refrigeration cycle?

A

Evaporator makes it low pressure, low temp VAPOR.

  • Compressor makes it high pressure, high temp VAPOR.
  • Condenser makes it high pressure, high temp LIQUID
  • Metering device makes it low pressure, low temp LIQUID
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49
Q

What does a compressor compress?

A

takes the low pressure, low temperature vapor and changes it to a
high-temperature, high-pressure, superheated vapor and delivers it to the condenser

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50
Q

Explain how cooling of a space occurs in a refrigeration cycle.

A

The heat is removed from the space and deposited outside.

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51
Q

Why will refrigerant migrate to the crankcase in a compressor?

A

Because of the vapor pressure difference between refrigerant and oil

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52
Q

What color is the compound gauge and what does the compound gauge measure?

A

Blue. It measures low pressure (psig) and vacuum (inches Hg)

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53
Q

What color is the high pressure gauge and what does it do?

A

usually red and measures the high side (discharge) pressure

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54
Q

What are three things the center hose is used for and what color is it usually?

A

Yellow. Can be connected to a recovery device, an evacuation vacuum pump, or charging device.

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55
Q

Why do we now use R-134A refrigerant

A

R-134A (also called HFC-134a) is the leading replacement option for retrofitting R-12 systems.

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56
Q

What must be done before scrapping a refrigerant container

A

Before scrapping disposable cylinders, all refrigerant should be evacuated and the pressure on
the cylinder should be at least 0 psig. Disposable cylinders use a one-way (check) valve.

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57
Q

What must be done to a cylinder (disposable or refillable) before scrapping it?

A

If cylinder is damaged and requires scrapping. Evacute it until its zero psig, the cylinder’s valve should be opened to allow air to enter, and the cylinder should be punctured with the valve still open (rendered useless)

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58
Q

How is recovery different from recycling?

A

To recover is to remove refrigerant in any condition from a system and store it in an external container without necessarily testing or processing it in any way.
To recycle is to clean refrigerant for immediate reuse by separating the oil from the refrigerant and removing moisture and acidity from the refrigerant.

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59
Q

How is recycling different from reclaiming?

A

To recycle is to clean refrigerant for immediate reuse by separating the oil from the refrigerant, but reclaiming is processing the refrigerant to the level of new product specifications as determined by chemical analysis.

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60
Q

What is temperature glide

A

Temperature glide is the difference in temperature that occurs when a refrigerant evaporates or condenses (changing from vapor to liquid or liquid to vapor) under constant pressure. This means the temperature in the evaporator and the condenser is not constant.

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61
Q

which type of blend won’t have a tempature glide?

A

azeotropic

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62
Q

Temperature glide can also be understood as the difference between the ____ point and the
________ point.

A

Dew and bubble points

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63
Q

The dew point occurs

A

when the saturation temperature in the evaporator causes

the refrigerant to change from a liquid to a vapor.

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64
Q

The bubble point occurs

A

when the saturation

point in the condenser changes the refrigerant from a vapor to a liquid.

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65
Q

One problem with blended refrigerants is that since the different refrigerants in the blend have
different vapor pressures, they _________________

A

they leak from systems at uneven rates

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66
Q

Charging a blended refrigerant

should be done in the

A

Liquid side

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67
Q

ester based oils do not mix with _______

A

Other oils

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68
Q

The refrigeration process is essentially _______

A

the transfer of heat from one place to another.

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69
Q

The vapor-compression refrigeration cycle is a repeating cycle consisting of
four main components:

A

evaporator, compressor, condenser and metering device.

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70
Q

What does the evaporator do

A

absorbs heat into the system from the space to be cooled (removes heat from the
space). The absorption of heat into the refrigerant causes it to boil.

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71
Q

Upon leaving the evaporator,

the refrigerant is high or low temp&pressure?

A

low pressure, low temperature vapor.

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72
Q

Upon leaving the compressor ,

the refrigerant is high or low temp&pressure?

A

High pressure, High temperature vapor.

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73
Q

where does the compressor send the high temp and high pressure to

A

Condenser

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74
Q

What does the crankcase stop

A

Oil migrating through the compressor.

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75
Q

Hermetically sealed compressors are often found
and they cannot be serviced as their shell is welded shut

True or false

A

True

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76
Q

You can operate a hermetically sealed
compressor when there is a dehydration vacuum in the system.

True false

A

False

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77
Q

Upon leaving the condensor,

the refrigerant is a high pressure, high temperature vapor.

A

that’s a trick question the condenser rejects the heat from the system and changes the refrigerant from a
high-temperature, high-pressure vapor into a high pressure, high temperature liquid

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78
Q

The condenser leads into the?

A

Metering device

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79
Q

what does the metering device do

A

The metering device reduces the pressure of the refrigerant and changes the high-pressure,
high-temperature liquid into a low pressure, low temperature liquid

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80
Q

After the the mettering device does the system repeat itself

A

Yes

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81
Q

______________ is an important tool for the technician that measures pressure readings at different points in the refrigeration system.

A

The gauge manifold set (also known as a service manifold)

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82
Q

The center port hose of the manifold is usually a what color.

A

Yellow

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83
Q

The scale on the high pressure side is a continuous scale and is usually calibrated to read from 0 to _____ psi.

A

500 psi

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84
Q

high pressure gauge hose color?

A

Red

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85
Q

compound gauge hose color?

A

Blue

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86
Q

Name three reasons recovery is important

A

Recovery is done in order to
have adequate supplies for service after production bans, prevent venting to the atmosphere, and
prevent stratospheric ozone depletion.

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87
Q

What standards must refrigerant recovery equipment meet and what component must all
Type I and Type II refrigeration systems have?

A

All refrigerant recovery and/or recycling equipment now manufactured must be certified and
labeled by an EPA-approved equipment testing organization to meet EPA standards

88
Q

What are two types of recovery equipment

A

System dependent and self-contained devices

89
Q

What should you tell a consumer who complains about the added cost and time of
recovering refrigerant?

A

Recovery is the law.

Recovery is necessary to protect human health and the environment.

All professional service personnel are duty bound to follow the law and protect the
environment.

90
Q

How should you handle recovery of a system that has mixed refrigerants?

A

When servicing a system that already has a mix of two or more refrigerants, the
mixed refrigerants must be recovered into a separate tank.

91
Q

After recovery, what are nitrogen and a filter-drier used for?

A

Nitrogen may be used to
flush debris out of the system after recovering refrigerant. The nitrogen may legally be vented to
the atmosphere. A suction line filter-drier should be installed to trap any debris that may cause
damage to the new compressor.

92
Q

What are the variables that affect the recovery rate and why is it important to have faster
recovery?

A

Size of refrigeration system and recovery equipment
Size of suction hose
Temperatures

The longer it takes to recover the refrigerants, the higher chance of emissions of the refrigerants
to the atmosphere

93
Q

For faster recovery, should the hose be

A. Longer length with a bigger diameter
B. Shorter length with a smaller diameter
C. Longer length with smaller diameter
D. Shorter length with bigger diameter.

A

D. Shorter length with bigger diameter

94
Q

If you smell a strong odor during recovery, what is most likely the problem and what
additional problems should you look for

A

If you smell a strong odor during the recovery process, it is likely that the compressor has burned
out. When recovering refrigerant from a system that has a burned out compressor, watch for
signs of contamination in the oil.

95
Q

Why is it necessary to dehydrate a refrigeration system?

A

The purpose of dehydrating a refrigeration system is to remove water and water vapor

96
Q

What happens if moisture is left in an operating refrigeration system?

A

The presence of moisture in an operating refrigeration system can create highly corrosive and toxic
acids

97
Q

What must be done before starting evacuation?

A

Before evacuating a system, it is

important to first recover all refrigerant and attain the mandated vacuum level

98
Q

What are the four factors that affect the evacuation time?

A

Size of equipment being evacuated. The larger the equipment, the longer it will take to
evacuate.
 Ambient temperature. The warmer the temperature, the faster it will evacuate. You may
heat the refrigeration system to decrease the evacuation time.
 Amount of moisture in the system. The more moisture in the system, the longer it will
take to evacuate.
 Size (capacity) of vacuum pump and suction line. The bigger the capacity of the
vacuum pump, the shorter the time.

99
Q

Can you increase the temperature of a refrigeration system for evacuation and if so, what
purpose does it have?

A

You may heat the refrigeration system to decrease the evacuation time.

100
Q

How long and what diameter should the piping connection to the vacuum pump be?

A

The piping connection to the pump should be as short in length as possible and as wide in
diameter as possible.

101
Q

How big should the vacuum hoses be in relation to the pump intake connection?

A 
Vacuum lines (hoses) should be equal to or larger than the pump intake 
connection.
102
Q

For accurate vacuum readings, where should the vacuum gauge be located?

A

as far as possible from the vacuum pump

103
Q

When should the measurement of vacuum for a system be done and how do we know
when dehydration is complete?

A

Measuring the vacuum of a system should be done with the
system isolated and vacuum pump turned off. If the system will not hold a vacuum, then it has a
leak. Dehydration is considered complete when the vacuum gauge shows that have reached and
held the required finished vacuum.

104
Q

What are the risks of inhaling (breathing in) refrigerants?

A

inhaling refrigerant vapors in the air can lead to heart irregularities and direct exposure to the skin can cause frostbite.

105
Q

What is the leading cause of refrigeration accidents leading to death?

A

Oxygen deprivation is the leading cause of refrigeration accidents that lead to death

106
Q

What personal protective equipment should you wear when handling refrigerants?

A

including safety glasses, butyl-lined protective

gloves and safety shoes.

107
Q

What are the requirements under ASHRAE standard 15-1994?

A

requires a refrigerant sensor that will sound an alarm and automatically start a ventilation system in occupied equipment rooms where refrigerant
(regardless of refrigerant type) from a leak will concentrate

108
Q

Under what conditions will alarm and ventilation sound under ASHRAE standard 15-
1994?

A

This standard specifies an oxygen sensor and alarm for A1 refrigerants, and a
refrigerant detector for all other refrigerants, as well as specifying ventilation requirements, but
may not prevent hazardous accumulations.

109
Q

What is the safest rating of a refrigerant according to the ASHRAE scale?

A

A1

110
Q

Why should oxygen or compressed air never be used to test leak a system?

A

Oxygen or compressed air, when mixed with refrigerants, can
cause an explosion

always use dry nitrogen

111
Q

When using nitrogen to charge a system, what piece of equipment should it be charged
through and where should a relief valve be located?

A 
When using dry nitrogen in service or installation, always charge through a
pressure regulator (make sure the nitrogen cylinder has a regulator on it) and insert a relief valve
downstream line from the pressure regulator.
112
Q

Where can you find the appropriate test pressures for a system?

A

read the design or test

pressure information located on the data plate on the low-side pressure valve.

113
Q

What are the two conditions to be aware of in observing relief valves?

A

The valves must not be installed in

series, and must be replaced if corrosion build-up is found within the body

114
Q

What can happen to refrigerants if they are exposed to direct flame or other excessive
heat?

A

Never expose refrigerants to open flame, live steam, glowing hot metal surfaces or excessive
heat. Some refrigerants, when exposed to flames or steam, change into toxic materials

115
Q

Before welding, cutting or brazing a refrigerant line, what should be done?

A

Always evacuate all refrigerant from the system before using any open flame for repairs.

116
Q

In case of a major refrigerant leak, what actions should be taken?

A

In the event of
a large leak, immediately vacate and ventilate the area or use Self Contained Breathing
Aparatus (SCBA)

Always
work with refrigerants in a well ventilated area to help avoid oxygen deprivation

117
Q

What types of cylinders can be used for recovery and how can you visually identify
them?

A

DOT approved refrigerant recovery cylinders are easy to identify as they
have yellow tops and gray bodies.

118
Q

How often should refillable cylinders be hydrostatically tested?

A

Refillable cylinders must be hydrostatically tested and date

stamped every five years.

119
Q

What must be done to a cylinder (disposable or refillable) before scrapping it?

A

If cylinder is damaged and requires scrapping. Evacute it until its zero psig, the cylinder’s valve should be opened to allow air to enter, and the cylinder should be punctured with the valve still open (rendered useless)

120
Q

Why should cylinders not be filled above 80% of their capacity by weight?

A

Overfilled cylinders may rise in internal pressure when exposed to heat, resulting in an
explosion.

121
Q

What are the three ways you can control the fill level of a refillable cylinder?

A

The fill level may be controlled by mechanical float devices, electronic float devices,
or weight

122
Q

Sight glasses are not an acceptable means for determining filling capacity.

T OR F

A

True

123
Q

If icing occurs on the sight glass, use a screwdriver to scrape the ice.

T or F

A

False

Use alcohol spray

124
Q

_________ cylinders are used only for virgin refrigerant and should ______ be used for recovery.

A

Disposable cylinders are used only for virgin refrigerant and should never be used for recovery.

125
Q

What is the EPA definition of a small appliance?

A

According to the EPA, a small appliance is one that is manufactured, charged, and hermetically
sealed in a factory and contains five pounds or less of refrigerant

126
Q

Does a PTAC fall under small appliances?

A

Yes,

A pressurized terminal air conditioner (PTAC) is a common name used for a hermetically sealed air conditioning system.

127
Q

Does a MVAC fall under small appliances?

A

MVAC or motorized vehicle air conditioning systems do not fall under the small appliance
regulations.

128
Q

What is the maximum amount of refrigerant a small appliance can have by definition?

A

contains five pounds or less of refrigerant.

129
Q

Who is responsible for complying with the laws if the EPA changes the laws after
technician certification

A

it is the responsibility of the technician to comply with any future changes in the law.

130
Q

What standards must recovery equipment manufactured before November 15, 1993 must
meet?

A

Recovery equipment manufactured before November 15, 1993 must be capable of recovering
80% of the refrigerant whether or not the compressor is operating or achieve a 4 inch vacuum
under conditions of ARI 740.

131
Q

What standard must recovery equipment manufactured after November 15, 1993 must
meet if using a compressor? With no compressor?

A

must be capable of recovering 80% of the refrigerant without the compressor operating or achieve a 4 inch vacuum under conditions of ARI 740; be capable of recovering 90% of the refrigerant with the compressor operating or
achieve a 4 inch vacuum under conditions of ARI 740; and must be approved by an EPA
approved third-party laboratory

132
Q

What is a low-loss fitting and why is it needed?

A

Recovery equipment fittings must be equipped with low-loss fittings which can be manually or
automatically closed when disconnecting hoses in order to prevent refrig

133
Q

What does the service aperture on a small appliance typically look like?

A

the service aperture valve is typically a straight piece of tubing that is entered
with a piercing access valve.

134
Q

What should be done with leaks in small appliances?

A

When servicing a small appliance, it is not mandatory to perform a leak repair; however, it
should be done whenever possible.

135
Q

How can you tell what type of refrigerant is in a system?

A

One way to identify the refrigerant is by using the

temperature/pressure chart

136
Q

Find the pressure for: R-12 refrigerant at 80ºF, R-22 at 70ºF and R-134A at 90ºF.

A

R-12 at 80ºF: 84.2PSI
R-22 at 70ºF: 121.4PSI
R-134A at 90ºF: 104.2

137
Q

What might happen if a cylinder containing mixed refrigerants is given to a reclamation
center?

A

If a reclamation facility receives a tank of mixed refrigerants, they may either refuse to process the
refrigerant and return it at the owner’s expense or they may destroy the refrigerant, but charge a
substantial fee.

138
Q

What is the difference between a self-contained recovery tank and a system-dependent
recovery tank?

A

Self-contained (active) recovery equipment uses its own power to recover the refrigerant from
systems and is capable of reaching the required recovery rates with or without the compressor operating.The recovered refrigerant in a self-contained system is stored in a pressurized
recovery tank.

A system-dependent (passive) recovery process captures refrigerant into a non-pressurized
container. The system-dependent equipment uses the system’s compressor, an external heat
source, or a vacuum pump to recover the refrigerant. A vacuum pump can only be used as a
recovery device in combination with a non-pressurized container and can not be used with selfcontained recovery equipment (pressurized container).

139
Q

What are two things that can cause high discharge pressures?

A

Not opening the tank inlet valve or

having excess air will cause higher discharge pressures.

140
Q

How can you check if a tank contains excess air or non-condensables?

A

Checking for air or non-condensables can be done by checking the pressure inside the recovery
tank

Safe note:when checking for non-condensables inside a recovery cylinder, allow the temperature
of the cylinder to stabilize to room temperature before taking a pressure reading

141
Q

What temperature must a cylinder be at to check for excess air?

A

Room tempature

142
Q

What type of system can a vacuum pump be used on for recovery?

A

A system-dependent (passive) recovery process

143
Q

When using a system-dependent recovery system with an operating compressor, where
should the refrigerant be recovered from? With a non-operating compressor?

A

When using a system-dependent recovery process with an operating compressor, run the
compressor and recover from the high side of the system.

When using a system-dependent recovery process with a non-operating compressor, it may be
necessary to access both the low and high side of the system to achieve the required recovery
level and it will speed the recovery.

144
Q

How can you release trapped refrigerants in the oil?

A

In order to release the trapped refrigerant from the
compressor oil, it will be necessary to heat and tap the compressor with a mallet several times
and/or use a vacuum pump.

145
Q

How will activating a defrost heater aid in the recovery process?

A

Will help to vaporize any trapped liquid refrigerant and speed up the process.

146
Q

When should piercing type valves be used? What is a common problem with these
valves?

A

Only on copper or aluminum tubing, they tend to leak over time.

147
Q

What are some other small refrigeration systems that contain other types of refrigerants?
Should these refrigerants be recovered with standard EPA equipment?

A

Appliances in campers/recreational vehicles. No.

148
Q

After installing an access fitting, if the system

pressure is 0 psig, should you start the recovery process?

A

After installing an access fitting, if the system

pressure is 0 psig, do not start the recovery process.

149
Q

What should be done before charging a new system with refrigerant?

A

the unit should first be pressurized with nitrogen (classified as an inert gas) and leak checked.

150
Q

What tools can you use to find general area of leaks and pinpoint leaks?

A

Using an electronic or ultrasonic leak detector will locate the general area of the leak. Once the
general area has been found, using soap bubbles will pinpoint the leak.

151
Q

Describe three ways you can visually look for leaksk

A

Look for traces of oil, using soup bubbles, look for excessive heat

152
Q

What are the leak repair requirements for comfort cooling appliances and commercial
appliances containing 50 pounds or more of refrigerant?

A

The leak rate exceeds 15% in comfort cooling appliances. The leak rate exceeds 35% in all commercial and industrial process refrigeration.

153
Q

What type of refrigerant was the most common before outlawing CFCs and HCFCs?

A

The most common refrigerant used before 1995 was R-22, but with the variety of refrigerants in
the market,

154
Q

What is the best way to determine the refrigerant type in the system?

A

technician should always read the nameplate to determine the type of refrigerant
used in the system.

155
Q

What is the purpose of the filter drier and when should it be changed?

A

Filter-driers are designed to remove moisture from the refrigerant in a system; however, in
order to remain effective, these must be replaced on a routine basis or any time a system is
opened

156
Q

How can you tell through a sight glass if there is excess moisture in the system?

A

by looking for color changes of the refrigerant.

157
Q

Using large vacuum pumps can lead to freezing of water in the system. What are two
ways the technician can help prevent freezing?

A

During evacuation of systems with large amounts of water, it may be necessary to increase pressure by introducing
nitrogen to counteract freezing

158
Q

Foaming at start-up may be found in what component? What does this mean?

A

Refrigerant in the oil will cause oil foaming in the compressor at start-up. A crankcase heater
(compressor heater) is often used to prevent refrigerant from migrating to the oil during periods
of low ambient temperature.

159
Q

What are two ways to measure a deep vacuum and what is the preferred method?

A

Vacuum can be measured in either microns or inches of mercury (inches Hg). The more
accurate and preferred method of measuring a deep vacuum is in microns

160
Q

What does inches Hg stand for?

A

inches of mercury

161
Q

When evacuating a vapor compression system how many microns does the vacuum need
to achieve?

A

the vacuum pump should be capable of pulling 500 microns (or
29.90” Hg) of vacuum.

162
Q

Why should you never start a hermetic compressor when under deep vacuum?

A

Never start a hermetic compressor when under a deep vacuum as the
motor winding could be damaged if energized.

163
Q

What is a receiver, where is it located?

A

Systems using thermal expansion valves will have a receiver/tank on the outlet side of the
condenser, designed to hold liquid refrigerant

164
Q

what is the state of the refrigerant after leaving

the receiver?

A

When leaving the condenser directly or the

receiver, the refrigerant remains a high pressure/high temperature liquid until it goes to the metering device.

165
Q

What is the liquid line?

A

The line between the condenser and the metering device is also referred to as
the liquid line.

166
Q

Recovery equipment manufactured after November 15, 1993 must be certified by an _____
laboratory, be equipped with _____ fittings, and must meet stringent _______ standards

A

Recovery equipment manufactured after November 15, 1993 must be certified by an EPA
laboratory, be equipped with low-loss fittings, and must meet stringent vacuum standards

167
Q

System-dependent recovery equipment cannot be used on appliances containing more than _____
pounds of refrigerant.

A

System-dependent recovery equipment cannot be used on appliances containing more than 15
pounds of refrigerant.

168
Q

How many inches of mercury (inches Hg) vacuum is required for HCFC-22 Appliances
containing more than 200 pounds refrigerant using equipment manufactured after November 15, 1993? Equipment before 11/15/1993? What about other appliances under å
the same conditions?

A

HCHF-22 appliance* < 200 lbs. refrigerant 0 0
HCFC-22 appliance* > 200 lbs. refrigerant 4 10
Other high-pressure appliance* < 200 lbs. refrigerant 4 10
Other high-pressure appliances* >200 lbs. refrigerant 4 15
Very high-pressure appliance 0 0
Low-pressure appliance 25 25

169
Q

What does the EPA consider major repairs?

A

major repair means any maintenance,
service or repair involving the removal of any or all of the following components: the
compressor, the condenser, the evaporator or an auxiliary heat exchanger coil. A nonmajor repair would not fall into any of these categories.

170
Q

What exceptions are there for evacuation for non-major repairs?

A

Involving none major repairs its prescribed to again atmospheric pressure of 0 psig. There is a leak of this is unattainable.

171
Q

What can you do if you can’t reach the required evacuation levels on leaky equipment?

A

Repairs to leaky equipment. Appliances can be evacuated to atmospheric pressure (0
psig) if leaks make evacuation to the prescribed level unattainable.

172
Q

What steps are taken before using recovery equipment?

A
  1. Check the service valve positions.
  2. Check the oil level of the recovery unit.
  3. Evacuate and recover any remaining refrigerant from the unit’s receiver.
  4. Evacuate an empty recovery cylinder before transferring refrigerant to the cylinder.
173
Q

What types of hoses and couplings should be used during the recovery process? Why

A

Use quick couplers, self-sealing hoses, or hand valves should be used to minimize
refrigerant release when hoses are connected and disconnected.

174
Q

What common contaminants can be found in refrigerant oils?

A

Acids, moisture, and oil.

175
Q

What maintenance task should you take to help limit the damage of contaminated oils?

A

Check both the oil and filter on a refrigerant recycling machine

176
Q

Why might recovery equipment using hermetic compressors overheat?

A

Both recycling and recovery equipment using hermetic compressors have the potential to
overheat when drawing a deep vacuum because the unit relies on the flow of refrigerant through
the compressor for cooling, so be aware of this problem.

177
Q

If switching from recovering one refrigerant to another, what three steps must be taken
before recovering the new refrigerant? What if the refrigerant is R-134A?

A

Purge the recover/recycle equipment by recovering as much of the first refrigerant as
possible.

Change the filter.

Evacuate.

The only exception to this rule is for technicians working with R-134A, who must provide a
special set of hoses, gauges, vacuum pump, recovery/recycling machine, and oil containers to be
used with R-134A only.

178
Q

Describe two ways to speed up recovery.

A

Pack the recovery cylinder in ice and/or apply heat to the appliance.

Recover as much as possible in the liquid phase. In order to recover liquid refrigerant,
you must connect one hose to the system’s liquid line. After recovering liquid refrigerant,
any remaining vapor is condensed by the recovery system.

179
Q

Under what circumstances can recovered refrigerant be reused?

A

After recovery, refrigerant may be returned to the appliance from which it was removed or to
another appliance owned by the same person without being recycled or reclaimed, unless the
appliance is an MVAC or MVAC-like appliance.

180
Q

MVAC stands for

A

Mechanical Ventilation Air Conditioning

181
Q

Where should you remove the refrigerant in a system that has a condenser below the
receiver?

A

Refrigerant should be removed from the condenser outlet if the condenser is below the
receiver.

182
Q

How must you recover refrigerant from a parallel system? Why?

A

When recovering from a system with parallel compressors, the technician must isolate a
parallel compressor system in order to recover refrigerant.

183
Q

Failure to isolate a parallel compressor system will cause what?

A

Failure to isolate a parallel compressor system will cause an open equalization connection that will prevent
refrigerant recovery.

184
Q

In a building that has an air-cooled condenser on the roof and an evaporator on the first
floor, recovery should begin from the suction line entering the evaporator.

T or F

A

False

from the liquid line entering the evaporator.

185
Q

Where do leaks commonly occur in low pressure systems? What about open-drive type
compressor systems?

A

The most common place for air or moisture to enter
the system is through leaks in gaskets or fittings. The shaft seal in open-drive compressor low
pressure refrigeration systems is particularly susceptible to leaks.

186
Q

When should a low pressure system be leak checked according to ASHRAE guideline 3-
1996?

A

The ASHRAE guideline 3-1996 states that if the pressure in the system rises from 1 mm Hg to a
level above 2.5 mm Hg during vacuum testing, the system should be leak checked.

187
Q

What does a purge unit do?

A

The purge unit prevents the accumulation of noncondensable substances (air and moisture) in order to keep the system clean and maintain efficiency

188
Q

what is a high efficiency purge unit?

A

A high efficiency purge system will expel very little refrigerant along with the air, while an inefficient purge unit will continue to leak refrigerants

189
Q

How does a centrifugal purge unit work?

A

A centrifugal system’s purge unit takes its suction from the top of the condenser, removes the air
from the system, and returns the refrigerant to the evaporator

190
Q

What are three visible ways to check for leaks in a low pressure system?

A

Excessive running of a purge system.

Continuous excessive moisture in the purge unit could indicate a leak in the condenser or the chiller barrel.

High head pressure.

191
Q

What needs to be done to leak check a low pressure system?

A

increase the pressure in the system by the use of controlled hot water or heater blankets. If using hot water or heater blankets is not possible, use nitrogen to increase the pressure.

192
Q

What are two ways you can increase the pressure in the system?

A

Hot water or heater blankets/nitrogen

193
Q

What can happen if you exceed 10 psig while pressurizing the system?

A

the rupture disk may fail

194
Q

How should a water box be leak tested?

A

be certain the water has been removed, then place the leak detector probe in
through the drain valv.

195
Q

What equipment should be used to test a tube?

A

a hydrostatic tube test kit.

196
Q

What are the leak repair requirements for comfort cooling appliances and commercial appliances containing 50 pounds or more of refrigerant?

A

The leak rate exceeds 15% in comfort cooling appliances.

The leak rate exceeds 35% in all commercial and industrial process refrigeration.

197
Q

What are the typical pressure settings for rupture discs on low pressure systems and recovery equipment?

A

The rupture disc on a low pressure system is 15 psig

198
Q

After removal of liquid, about how much vapor will remain in the system on a 350 ton R-11 chiller?

A

100 pounds

199
Q

How can you speed up the vapor recovery process?

A

A heater on the recovery vessel side

200
Q

In a system using a water cooled condenser, what components should be kept on and why?

A

the system water pumps, the recovery compressor, and the recovery condenser water should all be on. Water must be circulated through the tubes when evacuating refrigerant in order to prevent freezing the water.

201
Q

Where does the water typically come from in a water cooled condensing system?

A

the municipal water supply

202
Q

What parts of the system should be drained of water before recovering refrigerant?

A

the water sides of the evaporator and condenser

203
Q

How should a technician treat the oil before removal and why?

A

It should be heated to 130 degrees because less refrigerant will be in the oil

204
Q

Why should you never charge liquid refrigeration into a deep vacuum?

A

the refrigerant may boil and may lower the temperature enough to freeze the water in the tubes

205
Q

At what point in the system should you charge a low pressure system and what should you start the charge with?

A

Charge through the evaporator charging valve as this is the lowest point on a low pressure system.

206
Q

How can a technician determine when it is safe to start charging with liquid refrigerant?

A

First charge the system with vapor until the refrigeration saturation temperature reaches 36º F or the vapor pressure reaches 16.9” Hg vacuum.

207
Q

What are the required levels of evacuation for low pressure systems for equipment manufactured before 11/15/1993? How about after 11/15/1993?

A

25” Hg for equipment manufactured
before November 15, 1993.

25 mm Hg absolute for equipment manufactured after November 15, 1993

208
Q

Why should a technician wait a few minutes after reaching the required vacuum level and what should be done if the pressure begins to rise?

A

Once the required vacuum has been achieved, the technician should wait a few minutes to
monitor the system pressure. If the pressure rises, this indicates that there is still refrigerant in the
system (liquid or trapped in the oil) and the recovery process must be repeated

209
Q

What does the EPA consider a major repair?

A

any maintenance, service or repair involving the removal of any or all of the following components: the compressor, the condenser, the evaporator or an auxiliary heat exchanger coil.

210
Q

Where is the rupture disc on a low pressure centrifugal system and where should the disc be vented to?

A

it is located on the evaporator and discharge from the disc should be vented outside

211
Q

What problem can using large vacuum pumps lead to and how can a technician prevent it?

A

can cause trapped water to freeze.
increase pressure by introducing
nitrogen to counteract freezing.

212
Q

What step should you take for low pressure systems that will be sitting idle and why?

A

the pressure of the system should be increased to slightly above atmospheric pressure in order to prevent air accumulation in the system

213
Q

ARI means?

A

ARImeans Air Conditioning and Refrigeration Institute. In 2007, the organization added the letter “H” to their name. AHRIstands forAir Conditioning, Heating and Refrigeration Institute.

214
Q

What color is the center port hose and what does it do?

A

The center port of the manifold is usually a yellow hose and can be connected to a recovery
device, evacuation vacuum pump, or charging device.

215
Q

Refillable cylinders must be hydrostatically tested and date
stamped every six years.

True or false

A

False

Yes hydrostatically tested but date stamped must be every 5 years

216
Q

What is the difference between a ternary blend and an azeotropic blend?

A

Ternary blends are a three part mixture that experience a temperature glide
Azetropics blends has two compounds that act as one so it doesn’t experience temperature glide

Hvac (29 decks)

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