Deck 13: Air Removal, Filling, and Purging

Question 1

A device that makes short work out of filling and purging residential and light commercial hydronic systems consists of a minimum 1-horsepower swimming pool pump mounted on a 30-gallon plastic trash barrel This device is called a(n) ____.

A) circulator
B) purge cart
C) air scooper
D) deaerator

Answer 1

B

Question 2

Circulators transfer maximum head energy to incompressible fluids (e.g., liquids).A mixture of water and air is an example of an incompressible fluid.

Answer 2

False

Question 3

A(n) ____ is capable of maintaining the system fluid in an unsaturated state of air solubility.This means that the water is always ready to absorb additional air from any areas of the system where it may be present.

A) air purger
B) coalescing media
C) microbubble air separator
D) hygroscopic air vent

Answer 3

C

Question 4

Properly designed and installed hydronic systems will always require constant manual air venting.

Question 5

Air contains oxygen, and oxygen in contact with ferrous metals creates ____.

A) oxides
B) antigens
C) bubbles
D) deaeration

Question 6

Glycol-based antifreezes tend to leave a slippery film on components and tools that eventually turn sticky.

Question 7

A large pocket of air trapped within a system can totally stop flow.This effect is often called air ____.

A) blockage
B) plugging
C) binding
D) trapping

Question 8

Low system pressurization is usually caused by not setting the make-up water system properly.

Question 9

Combined air and dirt separators, or a hydraulic separator with the same capabilities, are never desirable in situations where an older distribution system containing steel or iron piping or radiators will be interfaced to a new boiler.

Question 10

Air has much lower specific heat and density than water.

Question 11

If properly designed, a closed-loop hydronic system should rid itself of most air within a few days of initial start-up.

Question 12

The oxygen that causes corrosion is the same oxygen that forms water molecules.

Question 13

Circulators with internal spring-load check valves installed in vertical piping with upward flow are especially susceptible to air pockets.

Question 14

Dissolved air can also lead to gaseous cavitation.Gaseous cavitation occurs when the pressure on the fluid ____ the saturation pressure of the dissolved gases it contains.

A) equals
B) drops below
C) rises above
D) is double

Question 15

An automatic fluid feeder uses a small positive displacement pump operated by a pressure sensing switch to automatically pump fluid into the system when the pressure ____ a set minimum value.

A) reaches
B) drops below
C) exceeds
D) is stored at

Question 16

When air exists as bubbles, a moving fluid may be able to carry them along through the system.This is called ____ air.

A) entrained
B) fluid
C) deaerated
D) bubbly

Question 17

The air removal devices used in small hydronic systems can be classified as either high point vents or ____.

A) "bleeders"
B) central air separators
C) "coin vents"
D) deaerators

Question 18

Flow noise is generated when dissolved gases are released from improperly deaerated fluid due to a ____ in pressure.

A) increase
B) modulation
C) equalization
D) reduction

Question 19

Although water may appear perfectly clear and free of bubbles, it can still contain a significant quantity of air in solution.

Question 20

The need for fully automatic (unattended) venting in locations not easily accessed requires a different type of device.A(n) ____ air vent often provides the solution.

A) electronic
B) top-loaded
C) ergonomic
D) float-type