The two types of drive assemblies that are commonly used to turn fans and blowers are __________.

A(n) ________ is recommended on all installations to prevent noise transmission through the duct system.

The return duct system distributes air to the terminal units, registers, grilles, or diffusers in the conditioned space.

Plenum, extended plenum, reducing plenum, or perimeter loop are all types of ________.

A __________ is used to make a duct more rigid, which prevents it from swelling and making noises when the blower starts and stops.

Flexible round duct comes in sizes up to about 24 inches in diameter and 25 feet of length to a box.

A branch duct should be fastened to the main trunk line with a __________.

________ is a very thick, putty-like substance that is applied to the duct connections to help make the system airtight.

Two ways that fresh air can enter a structure are infiltration and ventilation.

Which of the following types of fan is used to move large amounts of air against a low static pressure drop?

The three pressures created by air moving through a duct system are:

Pressure in ductwork is expressed in which of the following?

Warm air heats a room better if distributed

Multiple-zone systems often use oversized ducts or a damper to alleviate the problem of excess air when only some zones are calling for conditioning.

The duct sizes on the air friction chart are expressed in which of the following?

Turbulence in airflow causes friction drop.

True or False: Air for cooling circulates better through the conditioned space when it is introduced to the space through floor registers.