Marine Refrigeration Week 2

Front 1

basic controls are those with

Back 1

start,stop,regulate, protect

Front 2

primary controls in marine refrigeration are

Back 2

start, and stop

Front 3

secondary controls are

Back 3

regulate,and protect

Front 4

the three basic types of controls are electric pneumatic and electronic. how are distinguished apart?

Back 4

the type of message they send or recieve

Front 5

which control devices are used as primary control for a refrigeration cycle

Back 5

pressurstat,hummidistat,thermostat, and a time clock are used as primary control for a refrigeration cycle.

Front 6

when the thermostat is used as a primary control for the refrigeration cyclce

Back 6

its located in various places depending on the type of system

Front 7

what is the difference between a bimetal thermostat and a mercury bulb

Back 7

bimetal has open contacts while a thermostat has an enclosed bulb

Front 8

what would cause flash gas to form in the liquid line

Back 8

a pressure drop in the liquid line would cause flash gas in the liquid line

Front 9

describe the expected observed conditions when a compressor is started after being idle for a long time

Back 9

excessive foaming during startup

Front 10

describe the normal set pints for a LPCO switch (also known as a low pressure cut off switch)

Back 10

cuts out at a lower pressure than it cuts in

Front 11

what does a thermostatic control device sense

Back 11

temperature of the space that its in

Front 12

describe the location of the txv sensing bulb with respect to the back pressure regulating valve, and explain the purpose of this location

Back 12

txv is before the backpressure regulator valve

Front 13

describe the location and purpose of a back pressure regulating valve

Back 13

in the suction line off the high temperature evaporator

Front 14

describe the normal sequence of events for the proper operation of a thermostatically controlled high pressure refrigeration system

Back 14

at set point liquid line solenoid valve shuts

low cuttout stops compressor

top range liquid line opens

allows compressor to start

Front 15

describe the flow path through the relief valve of a modern high pressure system

Back 15

relief valve relieves to suction side

Front 16

how do solenoid valves open and close

Back 16

solenoid valves open and close through electromagnetism

Front 17

list possible cause for and corrective measures required for a compressor that is short cycling on the low pressure cuttout switch

Back 17

the system has low refrigerant if its short cycling on low pressure cuttout switch, recharge the system

Front 18

list possible causes for and corrective actions required to correct a compressor that is short cycling on the high pressure cutout switch

Back 18

if the compressor is short cycling on high pressure, it has too much refrigerant, condenser is hot,

restore condenser flow

Front 19

if a compressor is not starting why is it not starting and how can you fix it

Back 19

check its power, it has low refrigerant, oil pressure cuttout

Front 20

describe the purpose and location of liquid strainer in a modern high pressure refrigeration system

Back 20

the purpose of the liquid strainer is to protect the metering device from contamination, located prior to the TXV

Front 21

List possible cause and corrective actions for liquid flood back

Back 21

causes for liquid floodback

improper TXV operation, evap full of oil, loss of fan flow, low load

Front 22

describe the conditions that could cause a high pressure refrigeration compressor to be noisy upon startup

Back 22

liquid slugging could cause the compressor to be noisy upon start up

Front 23

describe the condition that could cause a refrigerated space to be to cold

Back 23

a refrigerated space could be to cold because of too much refrigerant or imporoper thermostat conditions

Front 24

describe the causes for and corrective actions to correct a low pressure condition

Back 24

low pressure conditions could be caused by a clogged meter, slow charge

Front 25

describe the causes for and corrective actions to correct a high suction pressure condition coupled with a low discharge pressure condition

Back 25

high suction pressure condition coupled with a low discharge pressure condition can be caused by, refrigerant overcharge, dirty condensor, improper mounting of TXV and TXV bulb is loose or dirty

Front 26

concerning the toxicity of flourocarbons

Back 26

In their natural state flourocarbons are mildly toxic

Front 27

what are the two most practical refrigerant leak testing methods

Back 27

electronic sniffer,and bubble method are the two most practical leak testing methods

Front 28

which two conditions are most likely to cause a system to leak

Back 28

the vibration of the systme and open compressors are the two most likely things to cause leaks

Front 29

harmful chemical reactions between refrigerant and contaminants mixed with it double with

Back 29

the harmful chemical reactions double with every 18 degree rise in temperature

Front 30

a disadvantage of a oil miscible refrigerant is that

Back 30

the disadvantage of a oil misciable refrigerant is the refrigerant may dilute the oil, reducing its lubricating qualities

Front 31

as system pressure drops saturation temperature

Back 31

as system pressure drops the saturation temperature also drops

Front 32

what is specific volumes

Back 32

specific volume is the space a substance occupies per unit

Front 33

the larger the specific volume of a refrigerant

Back 33

the larger the specific volume of a refrigerant the larger the compressor and piping to move the refrigerant

Front 34

a tubing system often requires

Back 34

a tubing system often requires less pressure than a piping system to produce a given flow rate

Front 35

short straight runs of tubing do not take advantage of its natural tendency to withstand

Back 35

short runs of tubing do not take advantage of tubing's ability to withstand vibration

Front 36

the three most important factors to consider when selecting tubing

Back 36

the material the tubing is made out of, the inside diamater, and the wall thickness of the tubing

Front 37

copper tubing type k and l are available in

Back 37

K and L are available in two tempers

Front 38

copper water tubing type M is for use only with

Back 38

Copper water tubing type M is for use only with Solder fittings

Front 39

Corrosive fluids are most frequently carried by

Back 39

corrosive fluids are mostly carried by Plastic, or Stainless tubing

Front 40

What type of tubing is usually used to handle products intended for human consumption

Back 40

plastic tubing is usually used to handle products intended for humans

Front 41

can brass fittings be used with plastic tubing

Back 41

yes brass fittings can be used with plastic tubing

Front 42

when using a tubing cutter to cut tubing how do you use the cutter

Back 42

rotate the cutter around the tubing

Front 43

how do you cut hard tubing

Back 43

you cut hard tubing with a hacksaw

Front 44

in order to remove small chips of material left by cutting

Back 44

you should debur the end length of the tubing

Front 45

the reference mark for all tubing measurments is the

Back 45

the centerline of the tubing is the reference mark for all tubing

Front 46

in order to calculate tubing length through a bend,

Back 46

you need to know the typical radius of the bend

Front 47

how many directions can Manuel tubing benders operate in

Back 47

Manuel tubing benders can operate in one direction

Front 48

when making a 120 degree bend in a length of tubing you should line up the scribed mark on the tubing with a line tangent

Back 48

a line tangent to the 90 degree mark on the radius block

Front 49

tubing has a tendency after bending to

Back 49

tubing has a tendency to spring back a small amount after bending

Front 50

refillable refrigerant cylinders maximum refillable volume is

Back 50

a refillable refrigerant cylinders maximum refrigerant volume is 80%

Front 51

a common cause of compressor burnout is

Back 51

high head pressure is a common cause of compressor burnout

Front 52

Suction valve sticks open because of impurities in the system

Back 52

When suction valve is stuck open discharge pressure is lower while suction pressure is higher

Front 53

Crankcase heater helps with

Back 53

Crankcase heater helps keep oil out refrigerant

Front 54

What device takes oil out of the hot gas line and put it back in the compressor

Back 54

The oil separator takes oil out of the hot gas line and sends it back to the compressor

Front 55

Liquid slugging is a

Back 55

Liquid slugging is a liquid shot back to the compressor

Front 56

Liquid slugging is a

Back 56

Liquid slugging is a liquid shot back to the compressor

Front 57

Receiver is on the

Back 57

The receiver is on the liquid line

Front 58

On initial pull down

Back 58

split plant systems will be isolated from each other and use two compressors to pull it down. Once temperature is achieved they will be paralleled onto one compressor

Front 59

How do you operate a timer

Back 59

Push in the dial and adjust time.

Front 60

How does the Solenoid valve on a hot gas bypass valve decide the time to open

Back 60

It decides it's opening time based on a timer for the defrost cycle

Front 61

Is it normal for frost to form In a freezers evaporator

Back 61

It is normal for frost to form In a freezers evaporator

Front 62

The faster a contact opens

Back 62

The faster a contact opens the less arcing occours

Front 63

How many winding are running on a single phase motor evaporator and condenser fans

Back 63

On the single phase motor only the run winding is energized after start

Front 64

When placing electrical equipment how much should they plan to exceed the load by

Back 64

The electrical equipment should exceed expected load by 50%

Front 65

Weak overload protectors could cause what

Back 65

Weak overload protectors could cause short cycling

Front 66

What is short cycling

Back 66

Short cycling is frequently starting and stopping

Front 67

If there's a thermostat monitoring a liquid line Solenoid valve

Back 67

The thermostat is monitoring box temperature for the liquid line Solenoid valve

Front 68

The tail coil contact temp is

Back 68

The tail coil contact temp is at least 15 degrees cooler than box

Front 69

What operates a Solenoid valve

Back 69

Electromagnetism operates a Solenoid valve

Front 70

How much hydrogen does a full halogenated molecule contain

Back 70

Fully halogenated molecule contain no hydrogen

Front 71

Filling a cylinder more than 80% could cause

Back 71

Filling more than 80% could cause an explosion

Front 72

What do you use to pressure test

Back 72

Nitrogen should be used to pressure test

Front 73

Is R12 toxic when burned

Back 73

Yes R12 is toxic when burned

Front 74

When adding refrigerant to suction service valve what form should it be in

Back 74

The refrigerant should be added to the suction service valve as a vapor

Front 75

High head pressure can cause what and what's one cause

Back 75

High head pressure can cause compressor to burn out, can be caused by dirty condenser

Front 76

Overcharging can cause

Back 76

Overchargeing can cause short cycling on high pressure cut-out as well as normal head pressure with a normal box temperature

Front 77

Broken valves can cause a compressor to

Back 77

Broken valves can cause a compressor to stick or lock up

Front 78

How many cylinders can a reciprocating compressor have

Back 78

Reciprocating compressors can have 1-12 cylinders

Front 79

Compressor crankcase foaming will increase with what

Back 79

Compressor crankcase foaming will increase with the length of time a unit was secured

Front 80

Cut in means

Back 80

Cut in means start

Front 81

Cut out means

Back 81

Cut out means stop

Front 82

With an lpco what is true about cut in and cut out

Back 82

It cuts out at a lower set point than it cuts in.

Front 83

Psig in a system is relative to what

Back 83

Psig is relative to the amount of refrigerant in system

Front 84

A unit will not run

Back 84

Unit has broken timer

Front 85

Refrigerator section too warm

Back 85

Air duct not positioned correctly

Front 86

Refrigerator section too cold

Back 86

Defective airflow control

Front 87

Freezer and refrigerator section too warm

Back 87

Shortage of refrigerant

Front 88

Noisy operation of compressor

Back 88

Cabinet not level

Front 89

Unit cycles on overload

Back 89

Weak overload protector

Front 90

Stuck motor compressor

Back 90

Broken valve

Front 91

Use to check systems pressures

Back 91

A gauge manifold

Front 92

Used to bleed capacitors

Back 92

20k ohm 2 watt resistor

Front 93

Used to prevent freezing at door seals

Back 93

Mullion heater

Front 94

The common refrigerator refrigerant of today

Back 94

R134a

Front 95

May act as insulator resulting in poor cooling

Back 95

Ice

Front 96

Can be used to check door seals for leaks

Back 96

Paper

Front 97

Can be used to check for proper grounding

Back 97

Voltmeter

Front 98

The standard condition of refrigerant used in charging domestic or small commercial units

Back 98

For charging domestic and commercial units VAPOR

Front 99

The amount of refrigerant to be charged can be precisely measured with

Back 99

Digital weighing scale

Front 100

Liquid refrigerant in the compressor may cause

Back 100

Broken valves

Front 101

Most internal problems are due to

Back 101

Air and moisture

Front 102

Piercing valves may be

Back 102

Piercing valves may be braized or bolted on a line

Front 103

Condenser which uses water flowing through an inside tube to cool refrigerant in an outer tube is called

Back 103

Tube within a tube condensor

Front 104

Shell and tube refers to

Back 104

Shell and tube refers to water cooled condensers

Front 105

A number of evaporators connected to a single condensing unit

Back 105

Eight

Front 106

Controls the number of cylinders which are pumping

Back 106

Hydraulic or electric unloading device

Front 107

Location where the sudden change of some of the liquid flash gas occours

Back 107

Refrigerant control

Front 108

Shell and tube within a tube condensor mediums

Back 108

Water cooled

Front 109

Number of possible defrost systems

Back 109

Six

Front 110

Used on the suction line to ensure one way refrigerant flow

Back 110

Check valve is used on suction line to ensure one way refrigerant flow

Front 111

A water pressure regulating valve is operated by

Back 111

A water pressure regulating valve is operated by head pressure

Front 112

Two temperature valves are sometimes called

Back 112

Two temperature valves are sometimes called pressure reducing valves

Front 113

Two types of temperature valves are

Back 113

Two types of temperature valves are pressure operated and temperature operated

Front 114

Are types of compressor oil return systems

Back 114

Separator,regulator, and resivoir are compressor oil return syy

Front 115

If pressure drop of 1 psi for low temperature, or up to 6 psi for high temp systems what should be replaced

Back 115

If those pressure drops occur replace the filter drier

Front 116

It is often necessary to clean or replace the

Back 116

Clean or replace the strainer in a water valve system

Front 117

What is used to assure the return of oil in the compressor

Back 117

an oil seperator is often used to assure the return of oil to the compressor

Front 118

what maybe installed to red condensor movement being transferred into the high side or low sides lines

Back 118

vibration absorbers

Front 119

what do bubbles in the sight glass indicate

Back 119

bubbles in the sight glass show a lack of refrigerant

Front 120

if the expansion valve is stuck open what may happen

Back 120

if the expansion valve is stuck open may get frosting on the suction line

Front 121

improperly adjusted shut out switches may cause

Back 121

improperly adusted shut out switches may cause short cycling

Front 122

if the stewards leave the door open or don't fully close it what could happen

Back 122

if the stewards leave the door open could have decreased system efficiency and the compressor will continuously run

Front 123

restricted suction strainers can cause

Back 123

restricted suction strainers can cause low suction pressure

Front 124

a stuck open relief valve can cause

Back 124

a stuck open relief valve can cause a high suction and low discharge since relief valve sends flow back to suction side

Front 125

what controllers the compressor running

Back 125

the low pressure cutout switch controls the compressors running

Front 126

a broken timer could prevent the unit from what

Back 126

a broken timer could prevent the unit from running

Front 127

the difference between a follow through and a a surge type receiver is

Back 127

the way their piped and vented

Front 128

which of the statements is true about r22

Back 128

r22 is miscible at high side operating conditions

Front 129

when taking readings the suction service valve (at the compressor inlet) of an operating system

Back 129

when taking reading at the compressor inlet a pressure and temperature reading is required because the refrigerant is probably superheated

Front 130

the best combination to use in selecting a compressor of the smallest possible displacement size is a refrigerant that

Back 130

a refrigerant that is low in specific volume but high in latent heat of vaporization

Front 131

which is true about suction and hot gas lines

Back 131

it is true that both under sizing and over sizing are bad, but under sizing tends to be the least damaging.

Front 132

an easy way to test for flashing in the liquid line is with

Back 132

an electronic temperature sensor

Front 133

the liquid line needs insulation when

Back 133

the liquid line needs insulation when the air surrounding it is warmer than the refrigerant within it

Front 134

the first line of defense against a resonating hot gas line is

Back 134

the first line of defense against a hot gas line is installing a hot gas muffler

Front 135

the suction line needs insulation mainly to

Back 135

the suction line needs insulation mainly to prevent condensation of air moisture in it

Front 136

which group of refrigerants holds least water in solution thus forming free water more easily

Back 136

hydrocarbons hold least water in solution

Front 137

in order to avoid adding moisture to the system coils, piping and accesories

Back 137

in order to avoid adding moisture to the system coils, keep them capped until installation time

Front 138

the evacuation dehydration should happen

Back 138

evacuation/dehydration should happen after the system has proven to be leak tight, but before it is changed

Front 139

a evacuation manifold set

Back 139

a evacuation manifold set usually has 5 hoses

Front 140

a schrader valve core remover is useful on

Back 140

a schrader valve core remover is useful on small systems to speed up evacuation/dehydration

Front 141

when a system is leak tight but still wet, what will the vacuum indicator do after the vacuum pump is stopped, and valved off from the system

Back 141

the vacuum indicator will rise then level off above 500 microns

Front 142

moisture removal by charge replacement is not

Back 142

moisture removal by charge replacement is not a substitute for proper evacuation methods of dehydration

Front 143

disposable refrigerant usually contain how much refrigerant

Back 143

disposable refrigerant usually contain 30lbs or less

Front 144

a untagged refrigerant cylinder is found in the storage area it is white the refrigerant contents should be

Back 144

the untagged white refrigerant should be R12

Front 145

gauge manifold hoses for deep vacuum must be good to

Back 145

gauge manifold hoses for deep vacuum must be good to 29.90 hg vacuum

Front 146

when the gauge manifold is front seated it is turned

Back 146

when the gauge manifold is front seated it is turned clockwise all the way

Front 147

the benifits of a evactuation manifold over a standard manifold are

Back 147

the benifits of a evactuation manifold over a standard manifold are evaluation time is less

Front 148

the main difference between an inline service valve and a process valve is that

Back 148

the process valve simply provides access to the system while the inline isolates part of the system as well as providing service access

Front 149

a harding valve is

Back 149

a harding valve is a inline service valve

Front 150

a schrader valve is

Back 150

a schrader valve is a process valve

Front 151

Ice used is used in the charge migration method of refrigerant recovery to

Back 151

Ice used is used in the charge migration method of refrigerant recovery to lower the cylinder pressure

Front 152

the refrigerant recovery/recycle unit is normally connected to the system through the

Back 152

the refrigerant recovery/recycle unit is normally connected to the system through the UTILITY HOSE OF THE GAUGE MANIFOLD

Front 153

when using a recovery/recycle unit on a system in need of repair, the normal sequence of operation goes

Back 153

when using a recovery/recycle unit on a system in need of repair, the normal sequence of operation goes RECOVER,REPAIR,EVACUATE,RECYCLE AND RECHARGE

Front 154

The best way to determine the charge needed by a system that has had all its charge removed is by

Back 154

The best way determine the charge needed is by looking at the charge printed on the manufacturers nameplate

Front 155

in order to charge refrigerant as liquid into a system what must you do

Back 155

In order to charge refrigerant as a liquid you must flip the cylinder upside down

Front 156

When doing a full charge what does it mean when the bubbles disapear from the sight glass

Back 156

when the bubbles disapear it means there's saturated liquid at the sightglass

Front 157

when using the superheat method of charge adjustment, a superheat reading of 4F too high requires

Back 157

a superheat reading of 4F too high requires no charge adjustment

Front 158

its better to charge oil by drawing it into the compressor than by pouring it in because

Back 158

When oil is drawn in the compressor crankcase is not opened to contamination by the atmosphere, which does happen when pouring it in

Front 159

what component reverses coil function in a heat pump system

Back 159

a 4 way valve is the component reverses coil function in a heat pump system

Front 160

What is excessive blow-by

Back 160

When the piston goes up and down and less happens usually due to wear

Front 161

Discharge head valve stuck open causes what

Back 161

When the discharge head valve is stuck open discharge is low and suction pressure is lower

Front 162

Can excessive blow-by happen on a scroll compressor

Back 162

Excessive blow by can't happen on a scroll compressor

Front 163

What is the unloader

Back 163

A device that makes the discharge pump back into the suction

Front 164

If the unloader is stuck open

Back 164

If the unloader is stuck open discharge pressure will be low and suction pressure will be high.

Front 165

describe the conditions neccesary for R12 to be a health hazard

1

Back 165

R12 must be burned to be a health hazard

1

Front 166

describe the methods to remove moisture from a high pressure refrigeration system

2

Back 166

dehydration

2

Front 167

describe the results of not removing moisture from a high pressure system

Back 167

freezing the txv

Front 168

why are there bubbles in my sight glass

Back 168

the refrigerant charge is too low

Front 169

describe the purposes of liquid line in sight glass

Back 169

liquid line sight glass indicates moisture and state of charge

Front 170

describe the conditions that will cause and corrective actions required when frost forms on the suction line of a high pressure refrigeration system

Back 170

txv is stuck open so ya can either heat it with a hot air gun also check the sensing bulb

Front 171

describe the conditions that will cause and corrective actions required when frost or sweat forms on the crank case of a high pressure refrigeration system

Back 171

liquid returning to comperssor it will be evaporator related

Front 172

describe the indications of and corrective actions required when the air is trapped in a damn high pressure refrigeration system

Back 172

when the air is trapped in the system youll have high head pressure just remove the old refrigerant and place it with good refrigerant

Front 173

describe the relationship between temperature and pressure in a modern high pressure refrigerant system

Back 173

saturated at inlet and super-heated at outlet

Front 174

question-discuss the reasons for and corrective actions required when frost accumulates on the evaporator coils in a modern high pressure refrigeration system

Back 174

answer

reason- its colder than the freezing point, high hummidity, Or the TXV is stuck open

solution- reduce hummidity, put on defrost

Front 175

describe the results of a shitty leaking gasket in a walk in chillbox

Back 175

yet again increased hummidity, also the compressor will run for longer. because the gasket is a piece of WANKSTAIN apearantly

Front 176

Maggots-discuss the reason for and corrective actions required when the suction line is warmer than normal in a modern high pressure refrigerant system

Back 176

Its Bloody low on refrigerant so add refrigerant or there's a blockage of the refrigerant flow path

Front 177

describe the Damn effects of excess refrigerant in a modern high pressure refrigeration system PVT Pile

Back 177

Sir its the high suction and discharge pressure can be corrected by removing refrigerant sir

Front 178

Now maggot discuss the reasons for and corrective actions required when flash gas forms in the liquid line of a modern refrigeration system

Back 178

You will have a clogged strainer or loss of condser cooling causes flash gas, low subcooling

Front 179

how do you adjusting a txv

Back 179

you adjusting TXV through time and patience

Front 180

Describe the method to control water flow through a modern high pressure refrigeration condesor.

Back 180

INLET PRESSURE AND HEAD PRESSURE

Front 181

DESCRIBE THE EFFECTS OF SUPERHEAT BEING SET TO LOW IN A MODERN REFRIGERATION SYSTEM

Back 181

LIQUID RETURN TO THE COMPRESSOR CALLED SLUGGING

Front 182

DESCRIBE THE EFFECTS OF SUPERHEAT BEING SET TO HIGH IN A MODERN HIGH PRESSURE REFRIGERATION SYSTEM

Back 182

STARVED EVAP, HIGH BOX TEMP

Front 183

DESCRIBE THE FUNCTION OF AN INTERCHANGER IN A MODERN HIGH PRESSURE REFRIGERATION SYSTEM

Back 183

PROVIDE ADDITIONAL SUBCOOLING TO LIQUID, ADDITIONAL SUPERHEAT TO VAPOR LINE