quizes
Help!
|
|
||||
|---|---|---|---|---|---|
| discuss the procedure for a burn victim in the vicinity of energized electrical equipment | secure power, check vitals, provide comfort
🗑
|
||||
| what would provide the best protection from gas leaking from a refrigeration unit? | SCBA
🗑
|
||||
| Define a refrigeration ton. | 1200 BTU per hour.
🗑
|
||||
| describe the heat gained per. pound of refrigerant in the evaporator. | refrigeration effect
🗑
|
||||
| describe total heat. | latent & sensible = total
🗑
|
||||
| what kind of heat causes a change in temp | sensible heat
🗑
|
||||
| describe the heat compression. | heat removed by condenser from refrigent
🗑
|
||||
| define latent heat | change in state
🗑
|
||||
| what is specific heat | heat required per. unit mass to change one degree
🗑
|
||||
| define sensible heat | molecular motion seen on a thermometer.
🗑
|
||||
| In the refrigeration cycle, where will we find superheated vapor? | Inlet outlet of compressor
🗑
|
||||
| What is the metering device in a refrigeration system? | TXV = saturated liquid vapor mix
🗑
|
||||
| Describe the refrigerant when it leaves the metering device of the system. | Reducing flash gas
🗑
|
||||
| Why due we sub cool the refrigerant prior to the TXV? | To increase refrigerant effect by reducing flash gas.
🗑
|
||||
| What does the pressure in the control tubing of a TXV spend on? | Superheat in the tail coil.
🗑
|
||||
| Describe the condition when liquid is forced back to the compressor. | Flood back (liquid returning to the compressor)
🗑
|
||||
| Where does the refrigerant absorb the latent heat of vaporation? | Evaporator.
🗑
|
||||
| Describe where the latent heat of condensation is removed. | Condenser.
🗑
|
||||
| What PPE should be worn when handling contaminated oil? | Rubber gloves.
🗑
|
||||
| Define liquid slugging. | Liquid coming back to compressor from evaporator.
🗑
|
||||
| What is short cycling? | Frequent starting & stopping in a compressor.
🗑
|
||||
| If some refrigerants are burned, what is the result? | Odor,compressor burn out ,contamination in oil.
🗑
|
||||
| Describe the methods to determine if there is moisture in the refrigerant. | Color change in the moisture indicator.
🗑
|
||||
| Why do we install sight glass in the liquid line? | To see moisture, state of change.
🗑
|
||||
| What causes frost on the compressor suction line? | TXV (metering device) stuck open.
🗑
|
||||
| What causes the crankcase to sweat? | Flood back (liquid return to compressor)
🗑
|
||||
| What do you check first when the compressor doesn't start? | Power, fuses
🗑
|
||||
| What will result from the oxidation of the lube oil due to overheating? | Sludge
🗑
|
||||
| What causes crankcase oil to foam? | Refrigerant boiling out of solution with the oil
🗑
|
||||
| What do we do to prevent flashing in the liquid line? | Sub cooling in condenser.
🗑
|
||||
| When does an automatic compressor restart? | Suction pressure increases.
🗑
|
||||
| What causes the low pressure cutout switch to actuate? | Low refrigerant pressure.
🗑
|
||||
| What will happen if excessive foam occurs in the crankcase? | Bearing over heating.
🗑
|
||||
| What will cause the release of refrigerant from the oil/refrigerant mixture? | Sudden reduction of pressure at start up.
🗑
|
||||
| Define the refrigeration system between the expansion value & the compressor. | Low side
🗑
|
||||
| What components separate the high side from the low side? | Compressor, metering device
🗑
|
||||
| What does the compressor do? | Circulate refrigerante
🗑
|
||||
| What will cause the suction line temperature to increase? | Heat load increase
🗑
|
||||
| What occurs to the temperature of the refrigerant as it passes through the TXV? | Decreases to the lowest point
🗑
|
||||
| What will most likely occur if the evaporator coil becomes covered with frost? | Short cycle
🗑
|
||||
| What would cause high head pressure at the compressor | Dirty condenser coils
🗑
|
||||
| What will prevent the compressor from starting? | low refrigerant level will not cause L/P switch to acturate
🗑
|
||||
| What problems are assoc. with excessive circ of the lubricating oil with the refrigerant? | Evap temp will rise, too much oil in the system
🗑
|
||||
| Describe the operation of a refrigeration unit that is low on refrigerant? | Frequent cycling continuous starting
🗑
|
||||
| List the methods to determine if a unit is low on refrigerant | Bubbles in the sight glass
🗑
|
||||
| Describe the procedure to add refrigerant to the low side of an A/C system. | Add as a vapor to the suction side service value.
🗑
|
||||
| Describe the procedure for charging refrigerant. | purge charging line
🗑
|
||||
| What are the sources of moisture in a low pressure refrigeration system? | leaking tubes
🗑
|
||||
| Describe the procedure for admitting fresh air to a HVAC for the greatest efficiency. | As little as possible for proper ventaliation
🗑
|
||||
| What is the purpose of dehumidifiers in an A/C system? | Remove moisture
🗑
|
||||
| What type of refrigerant is R-12 | CFC
🗑
|
||||
| The ozone layer protects the earth from | UV
🗑
|
||||
| What chemical found in the upper stratosphere indicate that the ozone layer is being destroyed | Chlorine Monoxide
🗑
|
||||
| The state of the refrigerant leaving the condenser of a refrigerant system is? | h/t, h/p sub cooled liquid
🗑
|
||||
| Refrigerant entering the compressor of a refrigeration system is a : | L/T, L/P superheated vapor
🗑
|
||||
| Refrigerant entering the metering or expansion device of a refrigeration system is a : | H/T, H/P, sub cooled liquid
🗑
|
||||
| The low pressure gage is color coded | Blue
🗑
|
||||
| The component that changes a low pressure vapor to a high pressure vapor is: | Compressor
🗑
|
||||
| When heat is moved, the temp of the substance it moved from: | Drops
🗑
|
||||
| List the components that are contained in all mechanical refrigeration. | Metering Device, Evaporated, Compress, Condenser
🗑
|
||||
| List the four basic categories for the use of mechanical refrigeration | Comfort, Refrigeration, Process, Cryogenics (low temp work)
🗑
|
||||
| As the temp of any substance increase, the molecules which make it up vibrate: | Faster
🗑
|
||||
| When a substance changes state from a liquid to a gas, the spacing of its molecules: | Increase greatly
🗑
|
||||
| One pound of refrigerant will take up the most space in what state | Gas
🗑
|
||||
| List several good thermal insulator & therefore poor conductor? | Polystyrene = poor conductor
Copper, Aluminum = good thermal insulator
🗑
|
||||
| To the refrigerant technician the most important type of heat is: | Latent
🗑
|
||||
| As 32°F liquid water is heated we witness: | Sensible, Latent, Sensible
🗑
|
||||
| A fluid (liquid or gas) is called saturated when: | It contains all the heat it can w/out change of state
🗑
|
||||
| In terms of refrigeration language, the water we drink is: | Sub cooled
🗑
|
||||
| The difference between a D-X coil & a cooler is: | D-X coil = cools air
A Coolers = cools liquid
🗑
|
||||
| Your electric temp probe shows that the temp of the refrigerant in an evaporator is 40°F. It's condition is: | Need the pressure to determine refrigerant condition
🗑
|
||||
| Describe the shell on a chiller | Casing that encloses the evaporator & condenser
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
Rafael Leon