Unit 21 Evaporators

A typical superheat for an evaporator operating under normal conditions would be 8 to _____ degrees F.

12

If an evaporator has a pressure drop of 10 psig and the low side pressure is 15 psig, what is the pressure at the inlet of the evaporator? ____ psig

25

A typical evaporator operating temperature in an air-conditioning system is _____ F.

40

If an R-12 refrigeration system is operating with a 25.4 psig suction pressure, what is the evaporator superheat if the evaporator outlet temperature is 34 F? ____ F

8

"If a low temperature evaporator is forming excess ice, which of the following could be a possible problem?"

All of these answers are correct

A forced draft high temperature evaporator would _____.

BOTH have its fins very close together and not need to be defrosted

The forced draft medium temperature evaporator would _____.

Be defrosted by off cycle defrost

A refrigeration system designed for the storage of flowers or candy is considered a _____ temperature type.

High

A large capacity evaporator would probably have _____.

Multiple refrigeration circuits

The capacity of an evaporator is affected by _____.

all of these answers are correct

"If the application requires a coil design to operate below 32 F, there must be provision for _____."

defrost

A direct expansion type evaporator is also called a ______. flooded evaporator dry-type evaporator multi-circuit evaporator stamped evaporator

dry-type evaporator

If a high temperature evaporator is forming ice, where is the possible problem? ____ fan is not runnin

evaporator

The device used to feed refrigerant to multiple circuits in an evaporator is called a flow control.

false

A large capacity evaporator would probably have _____.

multiple refrigerant circuits

"When the velocity of the air moving over an evaporator is slow, the ""air film"" acts as an insulator and slows the rate of heat exchange."

true

A stamped plate evaporator usually does not use a fan to move air across it.

true

Fewer fins per inch on an evaporator allow more ice to build between defrost cycles.

true

The refrigerant in the evaporator must be colder than the air passing over it for heat transfer to the evaporator.

true

"During the defrost cycle of a forced draft low temperature evaporator, the evaporator fan would ______."

turn off

Excess evaporator superheat _____. is desired to prevent liquid from entering the compressor will reduce the cooling capacity of the system can be removed by removing refrigerant from the system will cause the system to go into defrost

will reduce the cooling capacity of the system