Accessories Ppt notes page 3+4

Question 1

Crankcase heaters: Purpose;

1. Prevents off cycle _______ of refrigerant by warming the oil in the crankcase
2. Prevents liquid _______ of refrigerant oil (flooded starts)

Answer 1

1. prevents off cycle migration

2. prevents liquid dilution

Question 2

Crankcase Heaters: Types;

1. Electrical (75watt)
   - Internal: insertion in a ___
   - External: Wrap _____
2. Coil _______
3. Oil ________

Answer 2

1. Electrical 75watt, Internal is insertion in a well and external is wrap around
2. coil discharge
3. oil separator

Question 3

Crankcase Heater: Purpose;

1. Minimizes the amount of ____ circulated through the system
2. excessive oil circulation causes reduced system ______ by reducing heat transfer within the evap coil
3. Especially important if the oil is not ______ with the refrigerant such as R-717 or R22 in low temp applications

Answer 3

1. oil
2. capacity
3. miscible

Question 4

Crankcase Heaters: Installation;

1. _______ line of the system
2. Return line back to ______ (with shut off valve)
3. separator should be

Answer 4

1. discharge line of the system
2. return line back to crankcase
3. separator should be insulated

Question 5

Liquid Line Heat Exchanger: Purpose;

1. Increase suction line ______ and increase liquid line ________
2. Make sure they have a bit of superheat to protect the _________
3. May help provide minimum _______ requirement
4. Tube within a tube: vapour in suction line is ______ than liquid in liquid line

Answer 5

1. increase suction line superheat and increase liquid line sub-cooling
2. compressor
3. superheat
4. colder

Question 6

Evaporator Pressure Regulator: (EPR)

Also known as;

1. Pressure reducer _____
2. Two ________ ______
3. ______ pressure valve

Answer 6

1. pressure reducer valve
2. two temperature valve
3. constant pressure valve

Question 7

Evaporator Pressure Regulator:

1. Location: At the ______ of the evaporator
2. Valve operation: maintain pressure which means it opens on _____ of _____
3. When inlet valve pressure is higher than spring it will ______ refrigerant to go through the valve
4. Open force is _____ and closing force is the _____

Answer 7

1. outlet
2. rise of inlet
3. allow
4. suction, spring

Question 8

Evaporator Pressure Regulator: Purpose;

1. To prevent evaporator from going below a predetermined _____ or ________
2. Types: (2) _____ operated and _____ operated

Answer 8

pressure or temperature

temp operated and press operated

Question 9

Evaporator Pressure Regulator: Applications;

1. Any application where an abnormally ____ temp could create a problem
2. On a system operating two or more condition spaces at _______ temps
3. On ______ systems one setting used for operating cycle and other setting used during ______ mode
4. Multiple Evap/Temp systems EPR is installed at the _____ of the warmest coil

Answer 9

1. low
2. different
3. ammonia, defrost mode
4. outlet

Question 10

Evaporator Pressure Regulator: Applications;

5. *Check valve must be located at the _____ of the ______ coil
6. Required if TD between warmest and coldest coils exceed __F
7. Controlled evaporators must not exceed ___% of grand total load

Answer 10

5. outlet of the coldest coil
6. 5F
7. 40%

Question 11

EPR Considerations;

1. At 40% EPR load, system may require capacity control using a _______ bypass valve to compressor suction, along with a de-superheating _______ valve
2. A ____ tank may also be required to prevent _____ cycling

Answer 11

1. discharge bypass valve, along with a de superheating expansion valve
2. surge tank, to prevent short cycling

Question 12

Solenoid Valve: Installations;

1. When brazing heat rapidly and direct flame away from valve _____ to protect it from ________
2. Must be _______
3. • Usually in ______ line could be found in _____ line for pump down or two temp applications
4. Most valves use _______ to seat the valve, mount valve _______

Answer 12

1. away from valve body to prevent overheating
2. anchored
3. • discharge line sometimes in suction line for pump down or two temp applications
4. Gravity, mount valve upright

Question 13

Check Valves: Purpose;

1. To ______ fluid flow
2. Allow refrigerant to flow in one _______

Answer 13

1. control

2. one direction only

Question 14

Check Valve: Types;

3. _____ gate

Answer 14

1. ball
2. magnetic
3. swing gate

Question 15

Check valve: Installation;

1. When brazing heat rapidly and direct flame away from the valve _____
2. Protect from ________
3. must be installed with the arrow pointing in the direction of ________ flow

Answer 15

1. away from the valve body
2. overheating
3. refrigerant flow

Question 16

Muffler: Purpose;

1. To ______ gas pulsation which helps reduce _______ transmitted to refrigerant lines
2. Used in _________ compressors

Answer 16

1. reduce gas pulsation to help reduce vibrations

2. reciprocating

Question 17

Muffler: Installation;

1. Mounted ________ or ________
2. horz install must ensure bulge is on ___ to prevent oil trapping
3. when brazing heat rapidly and direct flame away from ______
4. Must be ________
5. protect from _________
6. Installed with arrow point in direction of ref _____
7. installed _______ from compressor discharge

Answer 17

1. horizontally or vertically
2. top
3. body
4. anchored
5. overheating
6. flow
7. downstream

Question 18

Valves are installed at various locations in the refrigeration system to:

1. insulate equipment for ______
2. _____ portions of the system when refrigerant is not required in a certain area
3. provide manual _____-connection from one component of system to another

Answer 18

1. servicing
2. isolate
3. cross connections

Question 19

Valves Classified by design: Globe valve;

1. Used for ____ refrigerants
2. cast body able to withstand ____ pressures
3. Flow is essentially straight through from _____ to ______
4. most ______ valve in use
5. A _______ pressure drop than any other valve making them _________ on suction line or low pressure liquid line where pressure drop affects efficiency

Answer 19

1. all
2. high
3. inlet to outlet
4. common
5. higher, unsuitable

Question 20

Valves classified by design: Angle valve;

1. Used for ___ refrigerants
2. Cast body able to withstand ____ pressures
3. flow through valve is at ___ degrees relative to _____ and ______
4. they have lower resistance (pressure drop) than globe valves making them more suitable for use on ______ lines and low _____ liquid lines

Answer 20

1. all
2. high
3. 90 degrees relative to inlet and outlet
4. lower resistance pressure drop to flow then globe valves making them more suitable suction lines and low pressure liquid lines

Question 21

Valves classified by design: Gate valve;

1. Used in refrigeration systems with _____, ______, and glycols
2. They are not used with ________ primary refrigerants as they are not manufactured for this
3. gate valves are usually used up to ___mm pipe diameter over which they become physically too large and difficult to install

Answer 21

1. water, brine, and glycol
2. vaporizing primary refrigerants
3. 75mm diameter

Question 22

Valves classified by design: Butterfly valve;

1. Have a very low ______ drop and are economical and easy to install in pipe diameters _____mm and above
2. Require ______ connections
3. while suitable for primary and secondary ref, some problems exist with them holding _______ when using _______ refrigerants
4. Problem is the behaviour of the seating material when exposed to a mixture of ____ and _____. Hence these valves are best suited to water, brines, or glycols.

Answer 22

1. very low pressure drop and easy to install in pipe diameters 100mm and above
2. flanged
3. holding pressure when used with primary ref
4. ref and oil

Question 23

Valves classified by design: Ball Valve;

1. May be used with _______ refrigerants
2. May also be used with ______ refrigerants but are more expensive than gate valves or butterfly valves
3. they have the lowest _______ drop of any valve (when selected full port size in the wide open position)
4. They are best suited to ____ pressure pumped liquid lines

Answer 23

1. primary
2. secondary
3. lowest pressure drop
4. low pressure pumped

Question 24

Valves classified by design: Diaphragm valve;

1. used for ____ refrigerants
2. flow through the valve is ___ degrees parallel to the ______
3. ______ resistance to flow (pressure drop)
4. cast body able to withstand ____ pressure
5. Hermetic seal between _______, diaphragm, and _______

Answer 24

1. all
2. 90 degrees parallel to inlet
3. lower
4. high
5. bonnet, diaphragm, and body

Question 25

Valves classified by design: Access Valve;

1. Used to gain access to _____ systems
2. They are equipped with a _______ valve
3. Service lines ______ the schrader valve if equipped with a depressor

Answer 25

1. small
2. schrader
3. depress

Question 26

Access control valves are used to remove a _______ core while pulling a vacuum on a system

Answer 26

schrader

Question 27

Valves classified by design: Line Piercing Valve;

1. Used on small systems that do not have ______ valves
2. May be installed on _________ systems
3. Bolt on style tend to ____ as O ring deteriorates over time and exposure to system ___
4. Brazed on ______ valve (on a vapour line)

Answer 27

1. service valves
2. pressurized
3. leak, oil
4. saddle valves

Question 28

Split AC service valves:

1. made of ____ and used for ____ temperature and pressure applications
2. These valves are used with _________ refrigerants

Answer 28

1. brass, high

2. halocarbon

Question 29

Types of connection to piping: Screwed;

1. Used for ____ pressures
2. a usually confined to under ___mm due to difficulty in making screwed joints

Answer 29

1. all pressures

2. under 50mm

Question 30

Types of connection to piping: Flanged;

1. Available from ___mm pipe diameter and up
2. Usually used on pipe diameters ___mm and larger
3. Whenever removal from the line is contemplated for _________ purposes

Answer 30

1. 12mm
2. 50mm and larger
3. maintenance purposes

Question 31

Types of connection to piping: Welded in line;

1. Lightweight and easy to install compared to larger _____ and ______ valves
2. The valves are becoming less expensive in pipe diameters ____mm and over
3. The main disadvantage is the valve must be ____ out of the line if removal is necessary
4. They should be installed in a position where _________ may be easily performed

Answer 31

1. globe and angle valves
2. 100mm and over
3. cut out
4. maintenance

Question 32

Types of connection to piping: Brazed;

1. Used where _______ and _________ is a factor in application
2. Sil-foss is a ______ brazed filler

Answer 32

1. temperature and pressure

2. common brazed filler

Question 33

Types of connection to Piping: Soldered;

1. Used on copper piping where ____ temperatures and pressure is not a factor
2. Not used on ________ refrigerant lines
3. Used for ____ lines

Answer 33

1. high
2. primary
3. drain

Question 34

Types of connection to piping: Flared;

1. Used with ____ walled tubing up to ___mm pipe diameters
2. Used with standard wall tubing up to ___” OD

Answer 34

1. light walled up to 50mm

2. 7/8” OD

Question 35

Types of enclosures: Seal cap;

1. The valve packing and stem is enclosed with a _____ cap to prevent _______
2. Usually used with _______ since leaks cannot be detected by _____ and the refrigerant is relatively expensive

Answer 35

1. screwed cap, prevent leakage

2. halocarbons, can not be detected by smell

Question 36

Types of Enclosures: Exposed;

1. The valve packing and ____ is exposed
2. _______ can occur from the packing to atmosphere

Answer 36

1. stem

2. leakage

Question 37

Valve Stem Packing:

1. Provides a ____ between the system and surrounding environment
2. ________ and non-_________ packing

Answer 37

1. seal

2. replaceable and non-replaceable packing

Question 38

Valve Stem Packing:

Material must be compatible with _________ and _____ used

Answer 38

refrigerants and oils used