Term 1

What are the typical uses of the center port of gauge set?

Definition 1

Used during evacuation, charging and recovery procedures.

Term 2

What color are the gauges on a manifold gauge set?

Definition 2

Low pressure is blue, High pressure is red.

Term 3

What are the typical ranges of pressure measurements used on the gauges of a manifold gauge set?

Definition 3

High side is 0 to 500 PSIG; Low side is 0 to 350 PSIG and 0 to 30 in. Hg below atmospheric pressure.
-

Term 4

Is the refrigerant leaving a condenser at a high or low pressure? Is it a liquid or a gas?

Definition 4

High pressure, liquid.

Term 5

Is the refrigerant entering the expansion valve (variable metering device) a liquid or gas?

Definition 5

Liquid, high pressure.

Term 6

Is the pressure of the refrigerant entering the compressor high or low?

Definition 6

Low pressure vapor.
-

Term 7

Where in a refrigerant circuit does a liquid boil to absorb heat?

Definition 7

In the evaporator.

Term 8

The refrigerant in the suction line is a gas that has been heated above its saturation. What is this condition called?

Definition 8

Superheated vapor.

Term 9

What can cause liquid refrigerant to migrate to a compressor crankcase?

Definition 9

If the compressor is located in the coldest location in the circuit.
-

Term 10

List two conditions that can quickly damage a compressor that is starting to run?

Definition 10

Operating while in a deep vacuum or when the service valves are closed.

Term 11

What system failures require taking an oil sample?

Definition 11

A compressor burnout or if the unit has had a leak.

Term 12

Is flushing with refrigerant an acceptable tube cleaning method?

Definition 12

No.
-

Term 13

In addition to preventing and repairing leaks, what else should a technician do to conserve refrigerant?

Definition 13

Recover and recycle used refrigerants.

Term 14

What factors affect the speed of an evacuation?

Definition 14

Pump size, hose length, hose diameter, size of system to be evacuated, ambient temperature, suction line size, and the amount of moisture in the system.

Term 15

How should gauge set hoses be sized for use in evacuating a system?

Definition 15

Use the shortest length and the largest diameter possible for the quickest evacuation. At least as large as the vacuum pump inlet.
-

Term 16

When evacuating, what is the benefit of using short hoses with large diameters?

Definition 16

Reduces emissions, pressure drop and evacuation time.

Term 17

which connection determines the preferred size of hoses used with a vacuum pump?

Definition 17

The vacuum pump inlet.

Term 18

As the capacity and suction hose size increase, what happens to the time needed for an evacuation?

Definition 18

Time is reduced.
-

Term 19

What purpose is served by heating a system during dehydration?

Definition 19

To speed up moisture removal.

Term 20

Does a thorough evacuation remove moisture from a system?

Definition 20

Yes.

Term 21

What can happen to oil in the compressor if the moisture is left in an operating system?

Definition 21

The oil will form hydrofluoric and hydrochloric acids which will corrode the internal parts of the system.
-

Term 22

What is the result of over-evacuating a system?

Definition 22

No damage will be done.

Term 23

How can a system be leak checked using a low pressure gauge?

Definition 23

Vacuum reading will rise when vacuum pump is turned off.

Term 24

How close should the vacuum gauge be connected to the vacuum pump during evacuation?

Definition 24

As far away as possible.
-

Term 25

When measuring the vacuum of a system being evacuated, the system must be isolated. What must be done to the vacuum pump?

Definition 25

Turn it off and valve it off.

Term 26

What is ozone?

Definition 26

3 atoms of oxygen. It blocks much of the harmful ultraviolet radiation (uv-b) emitted from the sun and it keeps our earth's temperature stable.

Term 27

How much ozone can a chlorine atom destroy in the stratosphere?

Definition 27

One atom can destroy 100,000 ozone molecules.
-

Term 28

What is Ozone Depletion Potential (ODP)?

Definition 28

The ability of any chemical to deplete the ozone layer.

Term 29

What is CFC?

Definition 29

Chlorofluorocarbon.

Term 30

Which refrigerants are CFC's?

Definition 30

R-11,12,113,114.
-

Term 31

Which chemical in the CFC refrigerants does the most damage to the ozone layer?

Definition 31

Chlorine.

Term 32

What is an HCFC?

Definition 32

Hydrochlorofluorocarbons.

Term 33

Which refrigerants are HCFC's?

Definition 33

R-22,123.
-

Term 34

Which is more harmful to the ozone layer, a CFC or an HCFC?

Definition 34

CFC's.

Term 35

What is it about CFC's that make them more harmful to the stratosphere?

Definition 35

Chemical strength, they will not breakdown in the lower atmosphere.

Term 36

What is an HFC?

Definition 36

A fluorocarbon that contains no chlorine.
-

Term 37

Which refrigerants are HFC's?

Definition 37

R-134a,404a,407c,410a.

Term 38

What is the ODP of the HFC refrigerant?

Definition 38

Zero.

Term 39

Which refrigerants contain chlorine?

Definition 39

CFC's and HCFC's.
-

Term 40

Which refrigerants have high ODP?

Definition 40

CFC's.

Term 41

Which refrigerants have low ODP?

Definition 41

HCFC's, HFC's are zero.

Term 42

What is an azeotrope refrigerant?

Definition 42

A mixture of two or more compounds where the mixture behaves like a single chemical.
-

Term 43

Is one of the components of R-500 a CFC?

Definition 43

Yes

Term 44

Does stratospheric ozone help or hurt the work of the earth's protective shield?

Definition 44

It helps.

Term 45

What chemical in the stratosphere tells us ozone depletion is occurring?

Definition 45

Chlorine-monoxide.
-

Term 46

How do we know the chlorine in the stratosphere is coming from CFC's?

Definition 46

The increase in chlorine and fluorine present in the stratosphere, matches the increase in emissions of CFC's.

Term 47

How do we know CFC's get to the stratosphere?

Definition 47

From high altitude air sampling measurements.

Term 48

What role does the ozone layer play in protecting the earth?

Definition 48

It blocks much of the harmful ultraviolet radiation (uv-b).
-

Term 49

What are the effects on health from increased ultraviolet radiation?

Definition 49

Skin cancer, cataracts, human immunity is reduced.

Term 50

What are the effects on the environment?

Definition 50

Timber growth is reduced, crop yields lowered, marine life and the food chain are impaired.

Term 51

Is ozone depletion a problem for the United States only or a global problem?

Definition 51

A global problem.
-

Term 52

What is the Montreal Protocol?

Definition 52

A treaty that called for the reduction of production of CFC's.

Term 53

The Montreal Protocol calls for the regulation of what chemicals?

Definition 53

Ozone depleting compounds, CFC's, HCFC's, and Halons.

Term 54

On what date was the production and importation of all CFC's phased out?

Definition 54

In the U.S., after December 31, 1995.
-

Term 55

Where will we get replacements?

Definition 55

Through recovery of existing refrigerants.

Term 56

What steps are called for by the Clean Air Act?

Definition 56

Taxes on production and use, standards set for the recovery of refrigerants.

Term 57

What is prohibited by the Clean Air Act?

Definition 57

Venting.
-

Term 58

Do state and local laws have priority over federal law? Can they be less strict?

Definition 58

No. Cities or states can create their own laws but they must be at least as strict as federal laws.

Term 59

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?

Definition 59

Allows states and municipalities to create their own laws to prevent and monitor the release of CFC and HCFC materials into the atmosphere.

Term 60

By recovering refrigerants, we ensure adequate supplies and prevent venting. What else does the recovery of refrigerants accomplish?

Definition 60

Prevents stratospheric ozone depletion.
-

Term 61

The Clean Air Act phases out CFC/HCFC production and prohibits venting. What else does it require?

Definition 61

Standards to be set for recovery of all refrigerants prior to appliance service and disposal.

Term 62

Falsifying or failing to keep required records, failing to reach required evacuation levels and knowingly releasing CFC or HCFC refrigerants, are a violations of the Clean Air Act. What activity with a substitute refrigerant is also a violation?

Definition 62

Knowingly venting CFC's, HCFC's and their substitutes.

Term 63

Which refrigerants must be recovered prior to opening a system?

Definition 63

All refrigerants as of 11-15-1995.
-

Term 64

What releases of a CFC and HCFC are violations of the Clean Air Act?

Definition 64

Any knowingly vented refrigerants.

Term 65

On what date did it become illegal to vent CFC and HCFC refrigerants?

Definition 65

July 1, 1992.

Term 66

Which appliances are covered by Section 608?

Definition 66

Any device which contains and uses a class 1 or class 2 substance as a refrigerant and is used for household or commercial purposes.
-

Term 67

What is the primary reason the EPA requires a service aperture or process stub on all appliances?

Definition 67

For adding or removing refrigerant from the appliance.

Term 68

Who sets the regulations for recovery machines?

Definition 68

EPA.

Term 69

What is a "self-contained" recovery machines?

Definition 69

A recovery machine that has its own compressor to pump refrigerant out of the system.
-

Term 70

Is HCFC-123 a "low or "high" pressure refrigerant?

Definition 70

Low pressure.

Term 71

Is CFC-12 a "low" or "high" pressure refrigerant?

Definition 71

High pressure.

Term 72

What is the smallest container in which refrigerants may be sold to a Section 608 certified technicians.

Definition 72

20 pounds.
-

Term 73

What must you do to the refrigerant in an appliance before disposing of the appliance?

Definition 73

Recover refrigerant or verify that the refrigerant was previously recovered.

Term 74

Who is responsible for removing the refrigerant from household refrigerators prior to disposal?

Definition 74

The final person in the disposal chain. (Scrap metal recyclers, landfill owner, etc)

Term 75

What is the penalty for violation of the Clean Air Act?

Definition 75

Fines up to $27,500 per violation per day and possible loss of technician certification.
-

Term 76

How much is the bounty for information leading to a conviction?

Definition 76

Up to $10,000.

Term 77

What ca happen if a technician cannot demonstrate an ability to use recovery or recycling equipment?

Definition 77

May result in revocation of the technician's certification.

Term 78

What is the name of the process that removes refrigerant from a system and stores it without testing or processing?

Definition 78

Recovery.
-

Term 79

What is the name for the process that removes moisture and acids from refrigerant but does not test the refrigerant?

Definition 79

Recycling.

Term 80

What is the name for the process that removes moisture and acids from refrigerant and also chemically tests the refrigerant?

Definition 80

Reclaim.

Term 81

What must be done with reclaimed refrigerant before it can be legally resold?

Definition 81

Chemically tested to ARI Standard 700, the purity level of factory new refrigerant.
-

Term 82

What is the preferred instrument for detecting small leaks?

Definition 82

Electronic leak detector and Ultrasonic detector.

Term 83

What is an inert gas typically used in leak detection?

Definition 83

Dry nitrogen.

Term 84

What is typically indicated by a dehydrated system failing to hold a vacuum?

Definition 84

Leaks.
-

Term 85

What should be done when recovering the refrigerant form a system where the refrigerant has been improperly mixed?

Definition 85

Recover into a separate container?

Term 86

Can mixed refrigerants be reclaimed?

Definition 86

No.

Term 87

What precautions should be taken when recovering refrigerant from systems with multiple service valves?

Definition 87

Insure that liquid is not trapped between service valves.
-

Term 88

What is the effect of low ambient temperature on the time required to complete a recovery of refrigerant?

Definition 88

Increases recovery time.

Term 89

Technicians must explain to customers that recovery is necessary and it is required by law. What else should the technician tell the customer?

Definition 89

That all service personnel are duty bound to follow the law and protect the environment.

Term 90

What is different about any leaks in systems charged with a blended refrigerant?

Definition 90

Because they are blended, the ingredients will leak at different rates.
-

Term 91

What is "temperature glide"?

Definition 91

A family of lines depicting pressure versus temperature curve.

Term 92

What is ternary blend?

Definition 92

A blend of three different refrigerants.

Term 93

How should systems using blended refrigerants be charged?

Definition 93

In liquid form into the high side of the system.
-

Term 94

Is there a "drop-in" refrigerant for CFC-12?

Definition 94

No.

Term 95

How do you leak check an HFC-134a system with a partial charge (no HFC-134a detector available)?

Definition 95

Recover the remaining 134a and then pressurize the system with nitrogen and a trace charge of R-22 so you can use an HCFC electronic leak detector.

Term 96

What is the preferred oil to be used with HFC-134a?

Definition 96

Ployolester.
-

Term 97

Can ester based oils be mixed with other oils?

Definition 97

No.

Term 98

What does "hygroscopic" mean?

Definition 98

Oil that absorbs moisture easily.

Term 99

What lubricant is recommended for use with a ternary blend?

Definition 99

Depends on the blend: For HCFC's-Alkylbenze, For HFC's-Ployolester.
-

Term 100

Safety glasses and butyl-lined gloves should be worn for what procedures?

Definition 100

When operating recovery or recycling devices and when handling and refilling refrigerant cylinders.

Term 101

What safety component must be used whenever dry nitrogen is used to pressurize a system?

Definition 101

Pressure regulator.

Term 102

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 should a technician follow?

Definition 102

All of them.
-

Term 103

What is a Material Safety Data Sheet?

Definition 103

A sheet the states the safety ratings and precautions to be taken for use and handling of chemicals.

Term 104

What safety classification within the ASHRAE standard is the most safe?

Definition 104

A1.

Term 105

What is caused by tie inhaling of refrigerant vapors?

Definition 105

Heart irregularities or Asphyxia.
-

Term 106

What is the major causes of death involving refrigerants?

Definition 106

Oxygen deprivation.

Term 107

What breathing problem can be caused by CFC-12?

Definition 107

Asphyxia.

Term 108

How can ice be removed from a sight glass?

Definition 108

With alcohol spray.
-

Term 109

What must be done with a badly corroded relief valve?

Definition 109

It must be replaced.

Term 110

Where can you find the allowable test pressure on a system?

Definition 110

Unit data plate.

Term 111

Can oxygen be used to check for leaks? If not, why not?

Definition 111

No. Oxygen in the presence of oil under high pressure can be explosive.
-

Term 112

What is the likely result of heating a recovery cylinder with an open flame?

Definition 112

Refrigerant will decompose into a toxic material, venting of refrigerant int the atmosphere or the tank may explode.

Term 113

What is the primary purpose of a disposable cylinder?

Definition 113

For virgin refrigerant from the manufacturer.

Term 114

To what internal pressure should a disposable cylinder be reduced to for disposal?

Definition 114

Reduced to at least 0 PSIG.
-

Term 115

Should you ever use a disposable cylinder for refrigerant recovery?

Definition 115

No.

Term 116

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?

Definition 116

Puncture the container before disposal.

Term 117

For safety, refrigerant chlinders should not be rusted or damaged and always properly color coded. What additional step should also be taken with these cylinders?

Definition 117

Properly secured at all times.
-

Term 118

What is the proper color code for recovery cylinders?

Definition 118

Gray with a yellow top.

Term 119

What is the maximum percent by weight that a cylinder may be filled?

Definition 119

80%.

Term 120

What can happen if a cylinder is overfilled?

Definition 120

Hydrostatic pressure could cause the cylinder to explode.
-

Term 121

List three methods for measuring the fill level of a recovery cylinder.

Definition 121

Floats, thermistor type sensors, and weighing scales.

Term 122

Wow often must reusable cylinders be hydrostatically tested?

Definition 122

Every five years.

Term 123

Why must only refillable cylinders be used for transport?

Definition 123

Federal code of regulations title 49 (parts 100-177) states this.
-

Term 124

What must be affixed to a refrigerant cylinder prior to its shipment to a reclaimer?

Definition 124

DOT classification tag.

Term 125

What is the purpose of a DOT classification tag?

Definition 125

For transportation purposes.

Term 126

What is the correct shipping position for a refrigerant cylinder?

Definition 126

In a vertical or upright position with their valves at the top.
-

Term 127

What is the EPA definition of a small appliance?

Definition 127

Appliances typically charged at the factory with five pounds or less of refrigerant. Refrigerators and freezers designed for home use, room air conditioners, including window and PTAC units, package heat pumps, dehumidifiers, under the counter ice makers, vending machines and drinking water coolers.

Term 128

Does the EPA require the repair of leaks on small appliances?

Definition 128

Repair of leaks on small appliances is not required, but leaks should be repaired whenever possible.

Term 129

What EPA certification type must technicians have to service any appliance that EPA calls a "small appliance?"

Definition 129

Type 1 or Universal.
-

Term 130

What service aperture may be used on small appliance?

Definition 130

Access tubes or process tubes.

Term 131

What is the name for a fitting, used to connect a recovery device to an appliance, which can close to prevent loss of refrigerant form hoses?

Definition 131

Low-loss fitting. (shut-off valve)

Term 132

What is the primary purpose for using hand valves or self-sealing hoses when using a gauge set?

Definition 132

To prevent loss of refrigerant.
-

Term 133

Which refrigerants must be recovered under Section 608 of the EPA regulations?

Definition 133

CFC, HCFC and HFC refrigerant.

Term 134

Is there a "drop-in" refrigerant for CFC-12?

Definition 134

No.

Term 135

What is the replacement refrigerant for CFC-12 in household refrigerators?

Definition 135

HFC-134a.
-

Term 136

What can be determined by taking an accurate temperature and pressure reading of a container holding a recovered refrigerant?

Definition 136

Check for non-condensables and the type of refrigerant.

Term 137

When doing a non-condensables check, a recovery cylinder should stabilize in temperature before any readings are taken. Why?

Definition 137

To find the correct pressure for that temperature on a T/P chart.

Term 138

What is the internal pressure of CFC-12 refrigerant stored at 75 deg. F?

Definition 138

77 PSIG.
-

Term 139

What is the exception to the rule that says that someone servicing and appliance must have at least one self-contained recovery machine available at their place of business?

Definition 139

Only when the person is working on a small appliance.

Term 140

Ammonia, hydrogen, and water can be found in the refrigerators in some campers and other recreational vehicles. Should these compounds be recovered with EPA approved recovery equipment?

Definition 140

No.

Term 141

May the nitrogen used for purging or pressurizing a system be vented to the atmosphere?

Definition 141

Yes.
-

Term 142

When may a technician recover only 80% of the refrigerant in a small appliance?

Definition 142

In a system dependent recovery with a non-operating compressor?

Term 143

May a technician use a passive recovery machine for recovery from a domestic refrigerator?

Definition 143

Yes.

Term 144

What requirements are placed on recovery machines built after November 15, 1993?

Definition 144

Must be able to recover 80% of the refrigerant if the compressor is inoperative or 90% if the compressor is operative. Must be EPA certified.
-

Term 145

When using a recovery machine manufactured after November 15, 1993, what percentage of the refrigerant must be recovered in a household refrigerator with an operating compressor? What percentage if the compressor is NOT operating?

Definition 145

80%, 90%.

Term 146

Is a certified technician responsible for future changes in EPA regulations?

Definition 146

Yes.

Term 147

What type of certification is required to purchase CFC and HCFC refrigerants?

Definition 147

Type 1.
-

Term 148

What must be done with any regulated refrigerant vented from a graduated charging cylinder?

Definition 148

It must be recovered.

Term 149

What first step must you always take before starting a recovery of refrigerant form any equipment?

Definition 149

Check which refrigerant is being used.

Term 150

What is a "system-dependent" recovery machine?

Definition 150

System dependent recovery machines rely on the compressor of the system being serviced, or the pressure of the refrigerant to pump the refrigerant into a recovery drum.
-

Term 151

Describe a system-dependent (passive) recovery process for small appliances.

Definition 151

Evacuate or cool a cylinder. Connect the high and low hoses to the system. Pull refrigerant into the cylinder with vacuum or the low tank pressure.

Term 152

What two conditions require that you access both the high and low side of the system for refrigerant recovery?

Definition 152

When there is an inoperative compressor on the system or when necessary to reach required recovery levels.

Term 153

What are the benefits of accessing the low and high side access valves when recovering refrigerant from a system with an inoperative compressor?

Definition 153

It speeds up recovery, improves efficiency and may be necessary to reach required recovery levels.
-

Term 154

How should you access the system and should you run the compressor when using a system-dependent (passive) recovery on a refrigerator with an operable compressor?

Definition 154

Access the high side and run the compressor.

Term 155

Which access valve (s) should you connect to when recovering from a system with an operating compressor and a completely restricted capillary tube?

Definition 155

High side valve.

Term 156

When using a self-contained (active) recovery device, what two conditions can cause excessive pressure on the recovery machine's high side?

Definition 156

A recovery container that is not properly evacuated or one that has unopened valve.
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Term 157

Why should defrost heaters be turned on during a recovery from a small appliance?

Definition 157

To speed up refrigerant release from the oil.

Term 158

When should entrapped refrigerant from oil be recovered?

Definition 158

Any time oil is removed from a large system and on small appliances when using system dependent recovery with a non-operating compressor.

Term 159

What does striking the appliance compressor do during a recovery?

Definition 159

Helps to free refrigerant that may be trapped in the oil.
-

Term 160

A recovery machine should be checked daily for what?

Definition 160

Refrigerant leaks.

Term 161

Can a standard vacuum pump be used as a recovery machine?

Definition 161

In theory yes, but unlikely. First it would have to be certifiable, second it would have to be connected to a non-pressurized recovery container.

Term 162

Should technicians ever mix refrigerants in the field?

Definition 162

No.
-

Term 163

How should you recover refrigerant that is different from the refrigerant you usually recover?

Definition 163

Different refrigerants must be placed in recovery vessels containing the same type of refrigerant.

Term 164

What can a reclaimer do with any mixed refrigerant you ship to them?

Definition 164

They may either refuse to process and return it at owner's expense or agree to destroy the refrigerant for a substantial fee.

Term 165

To ship recovered refrigerant you must label the container and complete all necessary paperwork. What else should you do?

Definition 165

Use DOT approved cylinders.
-

Term 166

What federal agency sets the standards for portable refillable tanks or containers used to ship CFC or HCFC refrigerants?

Definition 166

Department of Transportation (DOT).

Term 167

Safety glasses and butyl-lined gloves should be worn fro what procedures?

Definition 167

When you are connecting and disconnecting hoses.

Term 168

Piercing valves are used for what purpose?

Definition 168

To allow access to the sealed system for recovery.
-

Term 169

On what materials are piercing valves used?

Definition 169

Copper or aluminum refrigerant lines.

Term 170

What should be done to a piercing type Schrader valve after it is installed on a charged system?

Definition 170

It should be capped after any service procedure.

Term 171

Why should solder-less type piercing valves be removed after completion of repairs?

Definition 171

To prevent leaks.
-

Term 172

What are the critical maintenance checks done to a Schrader valve?

Definition 172

Periodically checked for leaks and replaced if damaged.

Term 173

What does a pungent odor detected after opening a system mean?

Definition 173

It might mean acids are present due to a compressor burnout.

Term 174

What do you do if the oil is contaminated?

Definition 174

Tubing flushing might be required.
-

Term 175

What system pressure would indicate a recovery should not be performed?

Definition 175

0 PSIG.

Term 176

What are the current methods used to monitor the 80% fill level in a recovery tank?

Definition 176

Floats, thermistor-type sensors and weighing scales.

Term 177

Why do large refrigerant leaks cause suffocation?

Definition 177

Refrigerants will replace air in a confined space leading to possible oxygen starvation.
-

Term 178

Before entering an area of a large leak of refrigerant what apparatus must be worn?

Definition 178

Self contained breathing apparatus.

Term 179

What should be done if a large leak occurs and no breathing apparatus is available?

Definition 179

Ventilate the space and leave the area.

Term 180

Which acids are formed when refrigerant touches sources of high heat?

Definition 180

Hydrochloric and hydrofluoric acids and phosgene gas.
-

Term 181

What safety component must be used whenever dry nitrogen is used to pressurize a system?

Definition 181

Nitrogen tanks should be equipped with a regulator.

Term 182

What information does DOT require when shipping refrigerant cylinders?

Definition 182

Shipping papers must indicate the refrigerant type and number of cylinders.

Term 183

Which government agency sets the standards for refillable refrigerant cylinders used to transport CFC and HCFC refrigerants?

Definition 183

Department of Transportation (DOT).
-

Term 184

What component is always replaced after a a system is opened for service?

Definition 184

Filter-driers.

Term 185

What is the purpose of the moisture indicator in a sight glass?

Definition 185

To permit a check of moisture content in the system.

Term 186

What does "back-seating" a suction valve do?

Definition 186

Allows flow through the main line while closing the access port.
-

Term 187

What will non-condensables do to the pressures in a refrigerant circuit?

Definition 187

Increase discharge pressure.

Term 188

What causes oil foaming in a system and where does it normally occur?

Definition 188

Oil that is mixed with refrigerant will foam in the compressor crankcase.

Term 189

What system failures require taking an oil sample?

Definition 189

Compressor burnout or if the unit has had a leak.
-

Term 190

A vacuum pump that is too large can cause what problem?

Definition 190

It can cause moisture to freeze in the system?

Term 191

Where is a receiver typically installed on a system?

Definition 191

At the outlet of the condenser.

Term 192

What will be the boiling temperature of HFC-134a be at 0 PSIG?

Definition 192

-15 degrees F.
-

Term 193

Is it a requirement that recovery machines contain an oil separator?

Definition 193

No.

Term 194

Which refrigerant is typically used on a residential split system air conditioner?

Definition 194

HCFC-22.

Term 195

Is the refrigerant leaving a receiver a liquid or a gas? Is it at a high or low pressure?

Definition 195

Liquid, high pressure.
-

Term 196

What is the initial charging method of a system when the charge is specified at 70 pounds?

Definition 196

Charged in liquid state.

Term 197

Is the receiver on the high or low side of a system?

Definition 197

High side.

Term 198

What is the minimum recommended capability (measured in microns) of a vacuum pump used for evacuations?

Definition 198

Should pull a vacuum of 500 microns.
-

Term 199

What is the pressure of a CFC-12 machine at 72 deg. F while the machine is idle?

Definition 199

73 PSIG.

Term 200

What is the preferred unit of measurement for checking a deep vacuum?

Definition 200

Microns.

Term 201

Where is an accumulator located in a refrigeration system?

Definition 201

On the suction line before the compressor.
-

Term 202

To prevent freezing of any moisture in a CFC-12 system, vapor should first be charged until the pressure is at what level?

Definition 202

33 PSIG

Term 203

What gas should be used during an evacuation to increase pressure to prevent freezing?

Definition 203

Dry nitrogen.

Term 204

What is the purpose of a compressor heater?

Definition 204

To reduce the amount of refrigerant in the lubricating oil.
-

Term 205

How is moisture remaining from an evacuation removed from the refrigerant in a system?

Definition 205

By the filter-drier.

Term 206

What is the preferred method of leak checking a built-up system prior to charging?

Definition 206

Bubble solution.

Term 207

What would a technician initially look for during a visual inspection of a leaking hermetic system?

Definition 207

Stains around tubing and fittings.
-

Term 208

What is typically indicated by excessive superheat on a high-pressure system?

Definition 208

Undercharged system, possibly the result of a leaky system.

Term 209

Which refrigerant should be used for a trace charge during leak detection?

Definition 209

R-22.

Term 210

How do you leak check an HFC-134a system with a partial charge (no HFC-134a detector available)?

Definition 210

Recover remaining 134a, pressurize the system with nitrogen and a trace charge of R-22 so you can use an HCFC electronic leak detector.
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Term 211

For what purpose are soap bubbles used in leak checking?

Definition 211

For a visual check for leaks.

Term 212

Shaft seals on an open type compressor are susceptible to what failures?

Definition 212

Refrigerant leaks.

Term 213

What leak rate is permissible on industrial and process refrigeration?

Definition 213

Effective 6/14/93, any leak rate of 35% or more on equipment with 50 lbs. of charge or more must be repaired. Less than 35% is permissible.
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Term 214

What leak rate is permissible on equipment (other than industrial or process equipment) that contains more that 50 lbs. of refrigerant?

Definition 214

Less than 15% annually.

Term 215

What is the easiest way to check the type of refrigerant used in a packaged rooftop system?

Definition 215

By the equipment data plate.

Term 216

Refrigerant will recover fastest in which phase, liquid or vapor?

Definition 216

Liquid.
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Term 217

Which refrigerant line should a recovery machine be attached to in order to recover liquid refrigerant from a system?

Definition 217

To the liquid line.

Term 218

After a liquid recovery, what must be done with the vapor still in the system?

Definition 218

Vapor recovery bust be performed.

Term 219

Recovering in a vapor phase reduces unwanted loss of what?

Definition 219

Oil and unwanted contaminants from the system to the recovery machine and recovery drum.
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Term 220

On a high pressure system recovery, should the recovery cylinder be heated or cooled?

Definition 220

Cooled.

Term 221

What must be done to a recovery machine when changing to a different refrigerant?

Definition 221

Clean out all residual refrigerant, change oil, replace filters, evacuate machine by pump-out or another machine.

Term 222

What besides filters must periodically be changed out on a recovery machine?

Definition 222

Oil.
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Term 223

Recovered refrigerant can contain oil and acids. Name another compound found in refrigerants?

Definition 223

Moisture.

Term 224

What is the water source for a condensing coil on a water-cooled recovery machine?

Definition 224

Municipal water tap.

Term 225

What access location should you use when recovering from an air cooled system with its condenser several feet above the evaporator?

Definition 225

Suction line.
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Term 226

What access location should you use when recovering from a system with its condenser below the evaporator?

Definition 226

Liquid line.

Term 227

Before using a recovery unit, the technician should check service valve positions and check the recovery unit oil level. What additional step must be taken?

Definition 227

All solenoid valves should be open.

Term 228

What is the primary purpose for using hand valves or self-sealing hoses when using a gauge set?

Definition 228

To prevent loss of refrigerant when connecting and disconnecting hoses.
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Term 229

What can cause recovery equipment with a hermetic compressor to overheat when drawing a deep vacuum?

Definition 229

No airflow over the compressor body or no suction gas flow over the internal motors, or a combination of the two.

Term 230

What is the reason for not operating a hermetic refrigeration compressor while it is in a deep vacuum?

Definition 230

To prevent overheating the compressor motor.

Term 231

What is the reason for not starting a reciprocating compressor with its discharge service valve closed?

Definition 231

To prevent overheating the compressor motor.
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Term 232

When can a "system-dependent" recovery device be used?

Definition 232

On small appliances as long as the device meets EPA standards and the technician adheres to the servicing procedures specified for the recovery equipment. Cannot be used on systems with more than 15 lbs. of refrigerant.

Term 233

What vacuum level must you reach when recovering from a system with 38 pounds of R-502 using a recovery machine manufactured in 1995?

Definition 233

10 inches of Hg.

Term 234

What is EPA's definition of a "major repair"?

Definition 234

Any repair that involves the removal of the compressor, evaporator, condenser, or any auxiliary heat exchanger coil.
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Term 235

Prior to making a major repair, what vacuum level must you pull when using recovery equipment manufactured in 1996 on a unit with 215 lbs. of CFC-12?

Definition 235

15 inches of Hg.

Term 236

What vacuum level must you pull when using recovery equipment manufactured in 1992 when disposing of an appliance containing 12 lbs. of R-500?

Definition 236

4 inches of Hg.

Term 237

Under what circumstances may a technician recover the CFC refrigerant in an appliance to atmospheric pressure only?

Definition 237

if leaks are in the system or if recovery to target levels would contaminate the refrigerant.
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Term 238

What procedure should be performed on an empty recovery cylinder before it is used for storing recovered refrigerant?

Definition 238

It must be evacuated of all non-condensables.

Term 239

What may legally be done with the refrigerant recovered from a system in order to replace a condenser coil?

Definition 239

Reused in the original system or transferred to another system with the same owner after it is checked so that it is free of non-condensables.

Term 240

When servicing an operating unit with a receiver, where should the recovery hoses be attached to the unit?

Definition 240

To the liquid line.
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Term 241

In order to recover from a system with parallel compressors, the individual compressors must be isolated. Why?

Definition 241

It isolates the refrigerant that must be recovered from the rest of the system.

Term 242

Which refrigerant (s) require and equipment room monitor per ASHRAE Standard 15?

Definition 242

All refrigerants.

Term 243

What protection is mandatory to protect a system against damage from excessive pressure?

Definition 243

A pressure relief device.
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Term 244

Are multiple relief valves connected in series or parallel?

Definition 244

Parrallel.

Term 245

Why is the use of a regulator required when using dry nitrogen?

Definition 245

To limit the outlet pressure of the nitrogen cylinder.

Term 246

How can ice be removed from a sight glass?

Definition 246

Cleaned with an alcohol spray.
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Term 247

How high should you pressurize an idle low pressure chiller to prevent air accumulation?

Definition 247

Slightly above atmospheric pressure.

Term 248

What effect does air in a chiller have on head pressure?

Definition 248

Raises head pressure.

Term 249

What system failures require taking and oil sample?

Definition 249

A leak or major component failure (compressor burnout).
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Term 250

Why must water be circulated through a chiller during refrigerant recovery?

Definition 250

To prevent freeze-up of the water as pressure is reduced on the refrigerant.

Term 251

What is the lowest access valve on a low pressure chiller?

Definition 251

The evaporator charging valve.

Term 252

Where is a centrifugal chiller's rupture disk attached?

Definition 252

At the evaporator.
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Term 253

What is the typical pressure setting for a low pressure chiller's rupture disk?

Definition 253

15 PSIG.

Term 254

Where is the outlet of a rupture disk discharged?

Definition 254

Outdoor for venting.

Term 255

How is a chiller typically charged?

Definition 255

Liquid through the evaporator charging valve.
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Term 256

What minimum saturation temperature needs to be achieved before liquid is charged into a chiller?

Definition 256

Above freezing, typically 36 deg. F.

Term 257

To prevent freezing of water when charging a chiller, what pressure should be reached with vapor before using liquid CFC-11?

Definition 257

16.9 inches of Hg.

Term 258

What could result from liquid refrigerant being charged into a chiller that is holding a 29 inch Hg. vacuum?

Definition 258

Can cause system water to freeze.
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Term 259

What function is served by a purge unit on a chiller?

Definition 259

Minimize the effects of contamination. To remove non-condensables.

Term 260

What is the most likely cause of air leaks into a chiller refrigerant circuit?

Definition 260

Gaskets and fittings.

Term 261

How is a purge unit connected on a low pressure chiller?

Definition 261

The inlet of the purge unit is typically connected to the top of the condenser.
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Term 262

Where is the suction of a purge unit connected?

Definition 262

The inlet of the purge unit is typically connected to the top of the condenser.

Term 263

What is a high efficiency purge unit?

Definition 263

It removes non-condensables that contain a low percentage of refrigerant. This adds to the value of the purge drum in refrigerant containment.

Term 264

Shaft seals on an open type compressor are susceptible to what failures?

Definition 264

Refrigerant leaks.
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Term 265

Purge units work best when they are not needed. How can purge unit operating time be reduced?

Definition 265

By regular leak checking and repairing any leaks on a regular schedule.

Term 266

What is the maximum pressure that can be used when leak checking a low pressure chiller?

Definition 266

10 PSIG on low pressure equipment that utilizes a rupture disk.

Term 267

What is the preferred method of leak checking a charged low pressure chiller?

Definition 267

By increasing the refrigerant pressure using an external heat source or running hot water through the chiller tubes not to exceed 10 PSIG.
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Term 268

Where should you check for leaks between a chiller refrigerant tube and the water box?

Definition 268

The chiller barrel can be emptied of all water and a leak check can be made at the drain valve with the water off. If the tubes themselves require a leak check, the check can be made with a hydrostatic tube test kit.

Term 269

What is a hydrostatic tube test kit used for?

Definition 269

To check for leaks in a chiller tubes.

Term 270

What leak rate is permissible on industrial and process refrigeration?

Definition 270

Effective 6/14/93, any annualized leak rate of 35% or more on equipment with 50 lbs. of charge or more must be repaired. Less than 35% is permissible.
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Term 271

What leak rate is permissible on equipment other than industrial and process equipment?

Definition 271

For appliances with 50 lbs. of charge or more an annual leak rate of 15% or more must be repaired. Less than 15% leak rate is permissible.

Term 272

According to ASHRAE 3-1990, what rise is permitted in vacuum level during a standing vacuum test?

Definition 272

Starting at 1mm of Hg., after 12 hours the vacuum reading should not increase to more than 2.5 mm of Hg.

Term 273

List two steps to reduce the run time of a purge unit.

Definition 273

Regular leak checks and repair any leaks.
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Term 274

Why should the water side of the evaporator and condenser be drained before recovering refrigerant from a chiller suspected of having tube leaks?

Definition 274

To prevent moisture form being drawn into the refrigerant circuit.

Term 275

If a purge unit is operating excessively, what problem can you expect to find?

Definition 275

Leaks.

Term 276

What condition would cause continuous excessive moisture collection in the purge unit of a low pressure refrigeration system?

Definition 276

Leaks between the refrigerant circuit and the water circuit.
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Term 277

Why should oil be warmed prior to removal from a low pressure chiller?

Definition 277

To vaporize any liquid refrigerant that might be trapped in the oil.

Term 278

After liquid recovery, what must be done with the vapor still in the system?

Definition 278

Vapor recovery must be performed.

Term 279

Is recovery of refrigerant from a low pressure appliance typically started with liquid or vapor?

Definition 279

Start with liquid removal.
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Term 280

Where is the connection made for the water supply used on a water cooled recovery unit?

Definition 280

Local water supply.

Term 281

What should be the maximum pressure on the discharge of a recovery machine for low pressure systems?

Definition 281

10 PSIG, because the rupture disk is set to open at 15 PSIG.

Term 282

What should be done with the water pumps during a recovery form a low pressure chiller?

Definition 282
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Term 283

What is EPA's definition of a "major repair"?

Definition 283

Any repair that involves the removal of the compressor, evaporator, condenser, or any auxiliary heat exchange coil.

Term 284

What recovery vacuum must be met on a low pressure appliance using a machine built in 1992?

Definition 284

25 inches of Hg.

Term 285

Why should you wait a few minutes after reaching the required recovery vacuum on an appliance to see if pressure rises?

Definition 285

To see if refrigerant is still trapped in the system.
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Term 286

Under what circumstances may the recovery from an appliance be stopped without reaching the prescribed level?

Definition 286

If the recovery would contaminate the refrigerant being recovered. (this level cannot exceed 0 PSIG.)

Term 287

Is it a requirement that recycling and recovery equipment be capable of handling more than one refrigerant?

Definition 287

No.

Term 288

Is it permissible to warm the refrigerant under EPA's regulations to pressurize a low pressure system to do a non-major repair?

Definition 288

Yes.
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Term 289

What final vacuum level is required for recovering refrigerant from a low pressure system if the technician is using recovery equipment manufactured BEFORE November 15, 1993? AFTER November 15, 1993?

Definition 289

25 inches of Hg, 25 mm of Hg. Absolute (equal to about 29 inches of Hg.)

Term 290

A vacuum pump that is too large for a particular system can cause what problem?

Definition 290

It can cause moisture to freeze in the system.

Term 291

How can you prevent moisture from freezing during dehydration?

Definition 291

You can raise the pressure with nitrogen and allow the ice to melt, then continue with the evacuation.
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Term 292

Are multiple relief valves connected in series or parallel?

Definition 292

Parallel.

Term 293

ASHRAE Standard 15 covers refrigerant level monitoring for what refrigerants?

Definition 293

All refrigerants.

Term 294

According to ASHRAE Standard 15, what is the standard for refrigerant concentration for a machine room that must not be exceeded without activating an alarm and starting ventilation in the machine room?

Definition 294

May not exceed the TLV-TWA. (Threshold limit value-Time weighted average.)
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Term 295

List four safety procedures that should be followed when working with liquid low pressure refrigerant.

Definition 295

1. Use refrigerant sensors in equipment room.
2. Avoid siphoning refrigerant by mouth.
3. Wear butyl-lined gloves.
4. Wear safety glasses.

Term 296

What is the toxicity and flammability rating of HCFC-123 per ASHRAE Standard 34?

Definition 296

B1.