What is the purpose of the venturi on a one-pipe venturi system?
A) The venturi separates air bubbles from the circulating water.
B) The venturi creates a negative pressure at the main connection, drawing the necessary flow through the branch.
C) The venturi mixes the supply and return water for more even temperatures.
D) The venturi increases the pressure in the pipe to offset piping losses.
[Ques. 2] A water-source system that recirculates water in pipes buried in the ground is:
A) Considered a hybrid between an open- and a closed-loop system.
B) An open-loop system.
C) A closed-loop system.
D) Called a quasi-open loop because it still must have an air gap at the circulating pump.
[Ques. 3] The output of an oil furnace ignition transformer can be tested:
A) Using the microamp scale on a multimeter.
B) Using a voltmeter that can read 1,000 V DC.
C) Using a voltmeter that can read 1,000 V AC.
D) With a special high-voltage probe that reduces the voltage to a level a standard meter can read.
[Ques. 4] When comparing duct materials, none have a lower friction rate or are as durable as:
A) Sheet metal. B) Ductboard. C) Flex duct. D) Fiberboard.
[Ques. 5] What is the recommended face velocity for a return air filter grille?
A) 1,0001,500 ft per minute B) 500600 ft per minute
C) 300400 ft per minute D) 6001,000 ft per minute
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