Exam 3

Question 1

The refrigerant in the condenser in a refrigeration system does what?

Answer 1

Rejects heat

Question 2

The condenser in a refrigeration system

Desuper heats the vapour…
Condenses the vapour from the compressor

SubCool the liquid refrigerant before it leaves…

Answer 2

From the compressor

The condense

Question 3

And normally operating water cold condensers operating with a 10°F differential between water in and water out. Is scale forms on the water tubes in the entering water is 85°F which of the following is possible?

Answer 3

Outlet water temperature will be lower than expect

And system head pressure will rise

Question 4

In a water, cool condenser with dirty condenser tubes the temperature difference between the refrigerant and the water will be when the tubes are clean?

Answer 4

Greater than

Question 5

The water circuit in shell and coil and tube within a tube coil condensers must be cleaned by what method?

Answer 5

Chemically

Question 6

In a water, cool condenser, a regulating valve is used to control the…

Answer 6

Refrigerant head pressure

Question 7

What can be used to maintain the head pressure system with the water glue condenser?

Answer 7

A water regulating valve

Question 8

The typical design temperature for the water entering a recirculating water system condenser is 85°F and most systems have a white degree rise across the condenser?

Answer 8

10°

Question 9

What is the most important parameter in cooling tower selection?

Answer 9

Entering wet bulb temperature

Question 10

What is the importance of condenser subcooling?

Answer 10

It prevents flashing in the liquid line

Question 11

True or false: the desired water flow through a condenser connected to a recirculating water system is approximately 3 gallons per minute per ton of refrigeration

Answer 11

True

Question 12

What problem will happen if head pressure drops too low

Answer 12

The metering device will not be properly

Question 13

If the compression ratio office system with the reciprocating compressor decreases the amount of refrigerant pump by the compressor, will…

Answer 13

Will increase

Question 14

Most of the heat energy in the suction vapour entering the compressor is is what

Answer 14

Superheated from the evaporator

Question 15

The temperature of the compressed gas leaving the compressor can best be described as

Answer 15

Very warm

Question 16

Rotary compressors are used primarily in

Answer 16

Residential and light commercial air conditioning

Question 17

The clearance volume of a compressor cylinder

Answer 17

Volume of the space between the bottom of the valve plate and the top of the piston at the top of the stroke

Question 18

If liquid enters the compression chamber of a reciprocating compressor, what can it damage?

Answer 18

Valves and piston rings

Question 19

The site glass on a semi herd compressor is used to allow light to enter the case to keep the oil warm

Answer 19

False

Question 20

Bolted together, motor compressor assembly, sometimes referred to as a semi hermetic type

Answer 20

True

Question 21

The compression ratio for an R2 two compressor operating with a 68.5 PSIG suction pressure and 260 psi G discharge pressure is

Answer 21

3.3

Question 22

What is the primary function of the condenser?

Answer 22

It rejects heat

Question 23

If the ambient is 78° in the condenser split is 30 what should be the condensing temperature?

Answer 23

Should be 48

Question 24

How does an HPR valve raise condensing temperature?

Answer 24

It backs up refrigerant into the condenser

Question 25

If the condensing temperature is 120°, what should be the temperature of the water leaving the water cooled condenser?

Answer 25

110•

Question 26

Cooling towers design with the fan, pulling air through them are known as what type of tower

Answer 26

Induce draft

Question 27

What is the difference between a hermetic and semi herd compressor?

Answer 27

The hermit has all parts, enclosed in a welded shell

Question 28

What is a suction cooled compressor?

Answer 28

It has suction valves in the cylinder head

Question 29

Why is lubrication important to a compressor

Answer 29

All moving metal services must have oil between them

Question 30

What is the proper level of oil in the site glass of a Copeland compressor?

Answer 30

Anywhere in the site class as long as the top of the oil is visible

Question 31

Detect system pressure is the service. Well stem should be in what position.

Answer 31

Mid seated or cracked

Question 32

What position at the discharge valve will cause damage if the compressor is running

Answer 32

Front seat

Question 33

What is the compression ratio of a compressor operating at 10 psi G suction and 235 psi e.g. head pressure

Answer 33

10 to one

Question 34

What is a primary advantage of scroll compressor over reciprocating compressor?

Answer 34

As few moving parts

Question 35

How do you raise a units condenser sub cooling

Answer 35

Clean the condenser

Question 36

What is a primary function of the comp

Answer 36

Increase refrigerant, temperature pressure and pump  vapour refrigerant

Question 37

The fresher in the middle of the condensers, the same as a pressure at the

Answer 37

Liquid line port on the outdoor unit

Question 38

Where does the hot gas from the compressor? Enter the water cool condenser

Answer 38

Where the warm water is leaving the condenser

Question 39

Why should condenser filters only be used if it is part of a regular scheduled maintenance program?

Answer 39

Condensers do not need filters

Question 40

In order to find the sub cooling bowl, the saturated temperature of the fridge and in the condenser in the actual temperature of the liquid refrigerant________ must be known

Answer 40

Exiting the condenser

Question 41

After the evaporator coil is clean, why should it be santized

Answer 41

To kill bacteria and deodorize the coil