Why would a 35F medium-temperature case need to defrost?
A) It is common for water to freeze at 35 in higher elevations.
B) The store manager might decide to maintain a lower box temperature.
C) The coil temperature for a 35F box operates below freezing.
D) A 35F temperature case does not need to defrost.
[Ques. 2] The most common sensing materials used in mechanical humidistats are:
A) Charged bulb and expansible tube. B) Diaphragm and bellows.
C) Nylon strips and hair. D) Bimetal strips and Bourdon tubes.
[Ques. 3] Why are the 90 percent condensing furnaces unique?
A) The flue gas affects the venting material at a greater-than-normal rate.
B) The venting of this type of furnace is made of PVC and is easy to seal airtight.
C) The flue gas is excessively hot and can cause fires if improperly used.
D) The venting material is rare, as it is no longer manufactured due to defects.
[Ques. 4] The most common fan used for moving air across outdoor condenser coils in residential air conditioning is:
A) Vane axial. B) Propeller.
C) Backward-curved centrifugal. D) Forward-curved centrifugal.
[Ques. 5] A refrigerated case that maintains a temperature of 28F would be classified as:
A) A cryogenic system. B) A low-temperature system.
C) A high-temperature system. D) A medium-temperature system.
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