WorksheetsFundamentals of Refrigeration 4
Total questions: 29
Worksheet time: 15mins
What is the function of the capillary tube in a refrigeration system?
Its function is to replace the liquid in the evaporator as rapidly as it boils away.
Its function is to increase the pressure of the refrigerant.
Its function is to cool the compressor.
Its function is to filter the refrigerant.
Which of the following is NOT an advantage of a cap tube?
No moving parts
Low cost to manufacture
Complicated operation
Equalizes in the off cycle
Which of the following is a disadvantage of a cap tube?
Charge is critical
System can adjust well for high load conditions
No moving parts
Low cost to manufacture
The greater the length of a capillary, the ______ its capacity to deliver liquid.
lower
higher
same
faster
The smaller the inside diameter of a capillary tube, the ______ its capacity.
lower
higher
constant
greater
The greater the overall restriction of a capillary, the lower its capacity.
True
False
If a capillary tube has the capacity to deliver a greater amount of liquid than is needed, what happens to the suction pressure?
The suction pressure will not drop past a certain point.
The suction pressure will increase indefinitely.
The suction pressure will become zero.
The suction pressure will fluctuate randomly.
If a capillary tube does not have the capacity to deliver liquid as fast as it is needed, what happens to the evaporator?
The evaporator will be starved.
The evaporator will overheat.
The evaporator will freeze.
The evaporator will leak.
A capillary tube of low capacity is indicated when the evaporator is starved while liquid banks up in the ______.
condenser
compressor
expansion valve
receiver
When is the refrigerant charge in a capillary system considered correct?
When a very small amount of liquid is collected in the bottom of the condenser and the evaporator is fully loaded, but no liquid is present in the suction line.
When the suction line is filled with liquid refrigerant.
When the condenser is completely empty of refrigerant.
When the evaporator is only partially loaded and liquid is present in the suction line.
A low temperature system will usually act as if it had a low capacity capillary tube until the temperature in the box approaches its ______.
normal low temperature
maximum pressure
ambient temperature
critical point
An extremely short unloading time may indicate what in the capillary tube?
Insufficient restriction in the capillary tube, but it may also indicate a blow by in the compressor.
Excessive restriction in the capillary tube, causing high pressure.
A clogged filter drier, leading to low refrigerant flow.
A malfunctioning expansion valve, resulting in overfeeding.
An extremely long running time indicates what?
Excessive restriction by capillary and/or overcharged of refrigerant (and is more likely).
Low voltage supply to the compressor.
Dirty air filters causing reduced airflow.
Faulty thermostat setting.
A capillary tube is plugged when the suction pressure drops into a deep vacuum and fails to equalize when the compressor is stopped. What may cause the plug?
The plug was caused by ice or wax if it opens after the capillary is warmed.
The plug was caused by a faulty compressor relay.
The plug was caused by excessive refrigerant charge.
The plug was caused by a broken thermostat.
An overcharge of refrigerant is indicated when the suction line frosts out or when the lower part of the condenser is flooded with liquid. The head pressure will normally be ______ than usual.
higher
lower
the same as
unaffected
A capillary system should never use a ______ or a sight glass.
receiver tank
filter drier
compressor
expansion valve
A split phase motor may be used with a capillary provided ample time is allowed for the system to ______ between cycles.
equalize
pressurize
cool
expand
The capillary system should never use a receiver tank or a sight glass.
True
False
Which of the following is NOT a step in setting a low pressure control as a cycling control with a capillary system?
Pick the temperature you wish to maintain
Pick your differential
Add your TD to the higher set point
Convert these settings to pressure to set your control
In the example provided, what is the PSIG cut in for a set point of 38°?
35.2
32.8
37.5
40.0
In the example provided, what is the PSIG cut out for a set point of 22°?
22.4
18.7
25.0
20.1
The capillary tube operates on what principle?
Bernoulli's principle
Pascal's law
Capillary action
Archimedes' principle
Which of the following are the three indications of a plugged capillary system?
Frost on the evaporator, low suction pressure, and high superheat
High discharge pressure, low oil level, and noisy compressor
Low head pressure, high subcooling, and liquid line sweating
High suction pressure, low superheat, and warm evaporator
The proper charge on a capillary system is:
Positive
Negative
Neutral
Variable
The function of a capillary tube is:
to store energy
to regulate the flow of fluid
to generate electricity
to measure temperature
If you want to maintain a 34 degree F temperature on a R-12 system with a differential of 6 degrees and a TD of 10 degrees, what would be your cut in, cut out, and differential pressure setting?
Cut in: 34°F, Cut out: 28°F, Differential: 6°F
Cut in: 40°F, Cut out: 34°F, Differential: 6°F
Cut in: 44°F, Cut out: 34°F, Differential: 10°F
Cut in: 34°F, Cut out: 24°F, Differential: 10°F
An extremely short unloading time might be an indication of which of the following?
Efficient process or underloaded vehicle
Overloaded vehicle or equipment malfunction
Underloaded vehicle or efficient process
Equipment malfunction or efficient process
Sizing a receiver tank on a capillary system is typically based on which of the following factors?
Compressor horsepower
Refrigerant charge required for the system
Ambient temperature
Pipe diameter
The purpose of an accumulator on a cap tube system is:
To store refrigerant and prevent liquid from entering the compressor
To increase the pressure in the evaporator
To regulate the flow of refrigerant through the capillary tube
To cool the compressor motor