HVAC 4 commercial and
Refrigeration Final Questions and
Answers (Graded A)
On a low temperature defrost the fans stay running - ANSWER - False
On medium temperature reach an evaporator with a box design temperature of 38
degrees, we normally need to us a planned defrost scheme - ANSWER - False
On a medium temperature walk in system the thermostat can deenergize the liquid
line solenoid at set point - ANSWER - True
Medium temperature systems sometimes use heated defrost - ANSWER - True
Pump down systems protect compressors from slugging - ANSWER - True
A medium temperature meat case can be at 25 degrees - ANSWER - True
The higher the TD of an evaporator, the higher the humidity in the box? - ANSWER -
False
Off cycle defrost on a medium temperature systems use heaters and time clocks -
ANSWER - False
Evaporator temperature affects the btu rating of a compressor - ANSWER - True
A walk-in refrigerator and an A/C system are both R22 and the ambient air at their
condensers is 95°. The AC units condensing temperature will be - ANSWER - A.
About the same as the walk-in refrigerator
, The evaporator temperature Hass to be lower than the box temperature because -
ANSWER - A. He goes to cold, the heat in the box must transferred to the refrigerant
in the evaporator
The condensing temperature have to be higher than the ambient temperature
because - ANSWER - A. The heat goes cold, The heat in the condenser must transfer
to the ambient air
A scroll compressor has fewer moving parts than a reciprocating compressor -
ANSWER - True
Hot gas injected is into an evaporator for load control - ANSWER - True
The approximate box temperature of a medium temperature system is - ANSWER -
C. 35 degrees
On a refrigeration system that has a glide, what do we use to calculate superheat -
ANSWER - B. Dewpoint
How much discharge superheat do we expect on our refrigeration compressors -
ANSWER - C. 30-60 degrees
The condensing unit on a medium temperature refrigeration system runs...... than a
comfort cooling condenser in the same environment with the same refrigeration -
ANSWER - C. About the same
One checking for sub cooling on a 407 a refrigeration system you need to use the...
On a PT chart - ANSWER - C. Bubble point
The condensing temperature Hass to be higher than the ambient air temperature
because - ANSWER - A. He goes too cold, the heat in the condenser must transfer to
the ambient air
Refrigeration Final Questions and
Answers (Graded A)
On a low temperature defrost the fans stay running - ANSWER - False
On medium temperature reach an evaporator with a box design temperature of 38
degrees, we normally need to us a planned defrost scheme - ANSWER - False
On a medium temperature walk in system the thermostat can deenergize the liquid
line solenoid at set point - ANSWER - True
Medium temperature systems sometimes use heated defrost - ANSWER - True
Pump down systems protect compressors from slugging - ANSWER - True
A medium temperature meat case can be at 25 degrees - ANSWER - True
The higher the TD of an evaporator, the higher the humidity in the box? - ANSWER -
False
Off cycle defrost on a medium temperature systems use heaters and time clocks -
ANSWER - False
Evaporator temperature affects the btu rating of a compressor - ANSWER - True
A walk-in refrigerator and an A/C system are both R22 and the ambient air at their
condensers is 95°. The AC units condensing temperature will be - ANSWER - A.
About the same as the walk-in refrigerator
, The evaporator temperature Hass to be lower than the box temperature because -
ANSWER - A. He goes to cold, the heat in the box must transferred to the refrigerant
in the evaporator
The condensing temperature have to be higher than the ambient temperature
because - ANSWER - A. The heat goes cold, The heat in the condenser must transfer
to the ambient air
A scroll compressor has fewer moving parts than a reciprocating compressor -
ANSWER - True
Hot gas injected is into an evaporator for load control - ANSWER - True
The approximate box temperature of a medium temperature system is - ANSWER -
C. 35 degrees
On a refrigeration system that has a glide, what do we use to calculate superheat -
ANSWER - B. Dewpoint
How much discharge superheat do we expect on our refrigeration compressors -
ANSWER - C. 30-60 degrees
The condensing unit on a medium temperature refrigeration system runs...... than a
comfort cooling condenser in the same environment with the same refrigeration -
ANSWER - C. About the same
One checking for sub cooling on a 407 a refrigeration system you need to use the...
On a PT chart - ANSWER - C. Bubble point
The condensing temperature Hass to be higher than the ambient air temperature
because - ANSWER - A. He goes too cold, the heat in the condenser must transfer to
the ambient air
