Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Term 1: Accessories/Oil/Piping > RACT Unit 25 Overview > Flashcards

RACT Unit 25 Overview Flashcards

1
Q

Mechanical Controls:

  1. Start, stop, or modulate fluid flow and can be operated by ________ or _________
A
  1. pressure or temperature or other means

2. piping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Evaporator Pressure Regulator (EPR):

  1. Prevents the pressure in an evaporator from ______ below a predetermined pressure
  2. Positioning controlled by ____ pressures which are ________ pressure and ______ pressure
  3. Also referred to as _____ on rise of ____ pressure
  4. Only establish a ________ pressure and do not hold a _______ pressure or limit maximum pressure
A
  1. dropping
  2. two, evaporator and spring pressure
  3. open on rise of inlet pressure valves
  4. minimum, do not hold a constant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Multiple Evaporator Systems:

  1. Single compressor with _______ evaporators

EPR Valves:

  1. Allow each evaporator to operate at its own ________ and __________
  2. Are equipped with ______ valves to allow gauge readings on the evaporator side of the valve
  3. Common suction-line pressure can be obtained at the compressor ________ valve
A
  1. multiple
  2. at its own pressure and temperature
  3. schrader
  4. service valves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Electric Evaporator Pressure-Regulating (EEPR) Valves:

  1. Provide more accurate _________
  2. Designed to maintain _______ air temperature in the refrigerated case
  3. Controlled by a bipolar ______ motor

Locations:

  1. Single evaporator: evaporator _______
  2. Multiple Evaporators: suction line before the common suction ________
A
  1. Control
  2. discharge
  3. bipolar stepper motor
  4. outlet
  5. suction line before the common suction header
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Crankcase Pressure Regulator:

  1. Resembles an ____ valve
  2. Located close to the __________
  3. Keeps a low-temperature compressor from overloading during a ___ ____down
  4. Referred to as a ____ on rise of _____ valve
  5. Controlled by crankcase (outlet) pressure and its _______ pressure
A
  1. EPR
  2. Compressor
  3. during a hot pull down
  4. close on rise of outlet (CRO) valve
  5. spring pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Adjusting the CPR Valve:

  1. Should be accomplished on a hot pulldown or at least when the compressor has enough load that it is trying to run ________
  2. It is important to use an _______ on the compressor while adjusting the CPR valve to ensure that the amperage draw of the compressor does not exceed the full load amperage rating
A
  1. overloaded

2. ammeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Oil Separators:

  1. Installed in the ________ line
  2. Separate oil from the refrigerant and return the oil to the compressor _________
  3. Oil drops fall to the bottom of the ________
  4. Oil level raises a float and opens a ______
  5. Difference between _____ and ___-side pressures push oil back to the compressor
  6. Another type is the ______ oil separator
  7. Device needs to be kept ______
A
  1. discharge line
  2. crankcase
  3. separator
  4. opens a valve
  5. high and low side
  6. helical oil separator
  7. warm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Vibration Eliminators:

  1. Often necessary to protect the tubing at the ______ and ________ lines
  2. Eliminated on small compressors successfully with _______ loops
  3. Large ______ requires special vibration eliminators constructed with a bellows-type lining and a flexible outer protective support
A
  1. suction and discharge lines
  2. vibration loops
  3. large tubing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Crankcase Heat:

The crankcase heater;

  1. Designed to help combat refrigerant ________
  2. Holds oil in the compressor’s crankcase at a temperature _______ than the coldest part of the system

Common in air-conditioning systems

  1. Can be applied in _______ ways
  2. Only needed (and desired) during the ____ _____
A
  1. migration
  2. higher
  3. several
  4. during the off-cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Oil Pumps:

  1. Larger compressors have ______ oiling systems that usually have over __ horsepower
  2. Contain an oil pump located at the end of the compressors _______
  3. Keyed into the compressors ________
  4. Can be of the gear or _______ type
  5. Squeezes the oil to a ______ pressure which is referred to as the ___ oil pressure
A
  1. forced oiling systems that usually have over 3 horsepower
  2. crankshaft
  3. crankshaft
  4. gear or eccentric type
  5. higher pressure which is referred to as the net oil pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Low Ambient Controls:

  1. Used on systems that are operated year round to maintain _____ pressure

Methods used to keep the head pressure at an acceptable level;

  1. Fan cycling using a _______ control
  2. ___ speed control
  3. Air volume control using ______ and fan cycling
  4. Condenser _______ and condenser _______
A
  1. maintain head pressure
  2. fan cycling using pressure control
  3. fan speed control
  4. air volume control using shutters and fan cycling
  5. condenser flooding and condenser splitting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fan-Cycling Head Pressure Controls:

  1. Device opens on a drop in head pressure, turning condenser fan ____
  2. Device closes on a rise in _____ pressure, turning the condenser fan ___
  3. Fan cycling causes large _______ in the head pressure
  4. One application is the use of _______ fans
A
  1. off
  2. rise in head pressure, turning condenser fan on
  3. large variances
  4. multiple fans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fan Speed Control for Controlling head pressure

  1. As the outside temperature _____, the fan slows down
  2. As the outside temperature rises, the fan speeds ___
  3. Some controls monitor the refrigerants condensing __________
  4. Newer generation systems use ____, to control condenser fan motor speed
A
  1. drops
  2. up
  3. temperatures
  4. VFD’s
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Air volume Control for controlling head pressure:

  1. accomplished with a piston-driven ______ controlled with the ____-pressure refrigerant
  2. When there are multiple fans, the first fans can be cycled off using ________, and the shutter can be used on the _____ fan
A
  1. piston-driven damper controlled with high-pressure refrigerant
  2. using temperature, shutter can be used on the last fan
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Condenser Flooding and Condenser Splitting for controlling head pressure:

  1. Condenser flooding devices cause liquid refrigerant to move from an oversized receiver to the condenser in ____ weather
  2. And requires a large amount of refrigerant to flood the _______ in the winter
  3. Splitting is another way to reduce the amount of extra ________ charge
  4. It splits the condenser into two separate _______ condenser circuits
A
  1. in cold weather
  2. condenser
  3. extra refrigerant charge
  4. two separate identical
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pressure Switches and Controls: Start and stop current flow to components;

  1. Low pressure switch: _____ on rise in pressure
  2. High pressure switch: ____ on rise in pressure
  3. Low ambient control: _____ on rise in pressure
  4. Oil safety switch: has a _____ delay; _____ on rise in pressure
A
  1. closes
  2. opens
  3. closes
  4. time delay, opens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Low pressure control applied as a thermostat:

  1. Can be set to operate the compressor the maintain the space temperature in the cooler and to serve as a ___-charge protection as well
  2. No interconnecting wires must be installed between the inside of the cooler and the _______ unit
  3. Control is rated by pressure range and ______ draw of the contacts
A
  1. low charge
  2. condensing unit
  3. current draw
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

High-pressure control:

  1. Prevents compressor from operating at high _____ pressures
  2. Opens on a ______ in pressure
  3. Can be automatically or manually ______
  4. Control cut-in point must be above the pressure corresponding to the _______ temperature
  5. Some have a fixed differential of ___psig
  6. Some manufacturers specify a manual ______
A
  1. head
  2. rise
  3. reset
  4. ambient
  5. 50psig
  6. reset
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Oil Pressure Safety Control:

  1. Larger compressors use with _____ pumps
  2. Pump is connected to compressor _______ and oil is forced through ______ in crankshaft
  3. Measures ___ oil pressure
A
  1. oil pumps
  2. crankshaft, holes
  3. net
20
Q

The Solenoid Valve:

  1. Valve position controlled by a solenoid ______
  2. Normally ____ or normally ______
  3. Used to control ______ or _______ flow
  4. Valves must be installed with arrow pointing in direction of ______
A
  1. coil
  2. open or closed
  3. liquid or vapour flow
  4. flow
21
Q

Automatic Pumpdown systems: Sequence of pumpdown operation;

  1. Normally closed liquid-line solenoid valve controlled by a _________
  2. Thermostat opens when desired ____ temperature is reached
  3. The solenoid deenergizes and _______
  4. Comp continues to pump ref downstream of closed solenoid valve to the high side causing low side pressure to _____
A
  1. thermostat
  2. box temp
  3. closes
  4. drop
22
Q

Automatic Pumpdown Systems: Call for Cooling:

  1. When box temp rises, thermostat ______
  2. Liquid line solenoid is _______
  3. Refrigerant flows to _______
  4. when low side pressure increases, the low pressure control _____
  5. the compressor is once again _______
A
  1. closes
  2. energized
  3. evaporator
  4. closes
  5. energized
23
Q

Medium-Temp Refrigeration:

  1. Box temperature ranges from __F to 45F
  2. Coil temps are normally 10 to ___F cooler than the box
  3. Coil temp as low as ___F
A
  1. 34 to 45F
  2. 10 to 15F
  3. 19F
24
Q

Random or Off-Cycle Defrost:

  1. Most _______ type of defrost
  2. Occurs when refrigeration system has enough reserve capacity to cool more than the _____ requirement
  3. Air in the cooler can defrost ice from the coil and evaporator fans continue to ___
A
  1. common
  2. load
  3. run
25
Q

Planned Defrost:

  1. Defrost is controlled by a ______
  2. System goes into defrost at predetermined _____
  3. Defrost cycle is initiated during low _____ periods
  4. Systems in retail establishments often go into defrost when the store is ______
A
  1. timer
  2. times
  3. load
  4. closed
26
Q

Low-Temp Evaporator Defrost:

  1. Low-temperature evaporators operate below _________
  2. Must have planned ______
  3. _____ must be added, ______ or ________ heat
A
  1. freezing
  2. defrost
  3. heat must be added, internal or external heat
27
Q

External Heat Defrost:

  1. Usually accomplished with _______ heaters mounted to the evaporator coil
  2. Timer controls the following events:
    - Stopping evaporator fan and compressor
    - Energizing electric heaters and drain pan heaters
  3. Temp sensor may be used to terminate _______
A
  1. electric
  3. defrost
28
Q

Defrost Termination and Fan Delay Control:

  1. Temperature-activated, single-pole-double-throw switch controlled by a remote _______ bulb
29
Q

Refrigeration Accessories are devices that improve system _______ and service functions

A

performance

30
Q

Receivers:

  1. Tank-like device located in the _______ line
  2. Used to store liquid ________ after it leaves the condenser and should be ______ than the condenser
  3. May be installed upright or __________
  4. Refrigerant must enter the _____ of the receiver and be taken from the _____ to ensure it is 100% liquid
A
  1. liquid
  2. refrigerant, lower
  3. horizontally
  4. top, bottom
31
Q

King Valve on the Receiver:

  1. Located in the liquid line between the receiver and _________ valve
  2. Normally the valve is ____seated
  3. Has a _______ port to enable readings
  4. Many systems also contain a _______ valve which stops and starts liquid flow
A
  1. expansion valve
  2. backseated
  3. service port
  4. solenoid valve
32
Q

Liquid-Line Filter Driers

  1. Located in the ______ line
  2. Removes foreign matter from the __________
  3. Connected with _______ or _______ connections
A
  1. liquid
  2. refrigerant
  3. solder or
    flare
33
Q

Refrigerant Sight Glasses:

  1. Normally located anywhere liquid flow exists and anywhere it can serve a _______
  2. When installed just prior to expansion device it enables technician to determine if a solid column of________ is reaching the device
  3. When installed at the condensing unit it can help with _________
  4. May be supplied with a moisture _________
A
  1. Purpose
  2. liquid
  3. troubleshooting
  4. indicator
34
Q

Liquid Refrigerant Distributors:

  1. Used on multi circuit ________
  2. Located at the ______ of the expansion valve
  3. Designed to allow _____ ref to flow to all circuits
A
  1. evaporators
  2. outlets
  3. equal
35
Q

Heat Exchangers:

  1. May be placed in or at the ______ line leaving the evaporator
  2. Suction and liquid lines are connected to allow _____ to transfer between them
  3. Increase the amount of ________ in the liquid entering the expansion device
  4. Prevents liquid refrigerant from moving through the suction line into the __________
A
  1. suction line
  2. heat
  3. sub cooling
  4. compressor
36
Q

Suction Line Accumulators:

  1. Prevents liquid refrigerant from entering the __________
  2. Gives liquid a place to ________ before entering the compressor
  3. Should have adequate liquid holding ________
A
  1. compressor
  2. vaporize
  3. capacity
37
Q

Suction-Filter Driers:

  1. Good compressor ________
  2. Must be installed when system has become _________
  3. Most have some means for determining the _______ drop across the cores because even a small
    pressure drop can reduce the _______ of the compressor
A
  1. protection
  2. contaminated
  3. pressure drop, efficiency
38
Q

Refrigerant Check Valves:

  1. Allow refrigerant to flow in ____ direction
  2. Can be either the ____ type or magnetic type
  3. Must be installed with arrow pointing in the direction of refrigerant _____
  4. Cause some pressure drop, even when ______
A
  1. one
  2. ball type
  3. flow
  4. open
39
Q

Suction Service Valves:

  1. Normally attached to the _________
  2. Can never be totally _______
  3. Positions: ____seated, front______ and ___seated
A
  1. compressor
  2. closed
  3. front-seated, back-seated, mid-seated
40
Q

Discharge Service Valves:

  1. Located in the ________ line
  2. Used as a gauge port and to valve off the compressor for _______
  3. Should not be ____seated when the compressor is running except during closed-loop capacity tests
A
  1. discharge
  2. service
  3. front seated
41
Q

Refrigeration Line service valves:

  1. Hand-operated speciality valves used for ________ purposes
  2. Used in any line that may have to be valved ____ for any reason
  3. Two types: Diaphragm valve and ____ valve
A
  1. service
  2. off
  3. ball valve
42
Q

Diaphragm Valves:

  1. Same internal flow pattern as a _____ valve
  2. Can be tightened by hand enough to hold back _____ pressures
  3. Installed into the system with either a flare or ______ connection
A
  1. globe
  2. high
  3. flare or soldered
43
Q

Ball Valves:

  1. Straight-through valve with little pressure _____
  2. Advantage is that it can be opened or closed easily because it only takes a ___degree turn to either open or close it
  3. Known as a “quick open or close”
    _____
A
  1. drop
  2. 90 degree
  3. valve
44
Q

Pressure Access Ports:

  1. Used for taking pressure readings at places that do not have _____ ports
  2. ______ the line when attached
  3. Some can be attached while the unit is operating, may be _____ or ______ to the line
A
  1. service
  2. pierce
  3. bolted or soldered
45
Q

Relief Valves:

Release refrigerant from a system when predetermined ____-pressures exist

Term 1: Accessories/Oil/Piping (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions