How does a duct blaster measure air leakage in duct systems?
A) It measures the airflow required to maintain a specified pressure.
B) It uses a velocimeter to calculate the speed of the sonically diffused airstream.
C) It measures the time it takes the duct system to depressurize.
D) It measures the actual leakage area through reflected pressure waves.
[Ques. 2] How much vacuum must a fuel oil pump produce to move fuel oil 20 ft horizontally?
A) 20 5 = 4 in of vacuum B) 20 10 = 2 in of vacuum
C) 20 2 = 10 in of vacuum D) 20 1 = 20 in of vacuum
[Ques. 3] If the liquid oil acid test kit cannot be used, indicators may be used to connect to the:
A) Suction line. B) Gas exhaust.
C) Oil drain plug. D) Liquid refrigerant line.
[Ques. 4] How can you tell when a filter drier is stopped up?
A) You will see the accumulated debris in the filter's sight glass.
B) The plugged filter flag will pop out of the leaving flare port.
C) You will hear a whistling sound in the filter.
D) It will have a pressure drop of more than 2 psi across the filter.
[Ques. 5] How do mixing valves save energy?
A) By reusing loop water for domestic hot water
B) By delivering only enough heat to the loop to meet the load
C) By maintaining a hot loop regardless of outdoor temperature
D) By mixing costly boiler water with inexpensive domestic hot water
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