Unit 37 - Quiz

The pressure in a duct system is measured in:

The __________ or fan provides the pressure difference to force the air into the duct system, through the heat transfer surfaces in the conditioning equipment, through the grilles and registers, and into the room.

The atmosphere exerts a pressure of __________ at standard atmospheric conditions.

Measuring velocity pressure in a duct indicates the __________.

An air pressure measuring instrument __________

Why we use a reducing plenum system is to __________.

A(n) _________ degree F temperature difference from inside the duct to outside the duct is considered the maximum difference allowed before insulation is necessary.

If the equivalent length of a transition piece of ductwork is 10 feet and the main duct in series with it is 20 feet, what is the length used to estimate the total frictional loss?

What is an air conditioning systems capacity in tons if the supply air is moving through a 12" x 24" main duct at a velocity of 400 feet per minute.

If you were to use a vane anemometer to check air flow what velocity pressure would you use if your traverse readings were: 475, 500, 500, 450, 500, 525, 550, 500, 450, 500, 525, 475

One psi is equivalent to:

The main reason for using a reducing extended plenum system is to __________.

The forced-air system is different from a natural-draft system.

The duct pressure equals the velocity pressure plus static pressure.

Adjusting the tension on the belt will alter the rate at which air is moving through the system, but does not affect the amperage draw of the motor.

Canvas collars are generally made of canvas rather than other materials such as rubber.

Oversized duct systems cost more to fabricate and install and will also result in the slowing of the air as it flows through the duct.

The device used to put trunk duct or extended plenum sections together is called a drive clip.

Friction due to air rubbing the walls of the ductwork can be eliminated.

The main drawback of the extended plenum system is that the velocity of the air is lower as the air reaches the last takeoffs on the extended plenum.