Pneumatics

Question 1

Which of the following is not an advantage of using pneumatic controls?

A : simple operation
B : flexible application
C : Built in safety
D : Unreliable service

Answer 1

D: unreliable service

Question 2

On an uncontrolled open loop system which of the following statements is true?

A : saves energy
B : wastes energy
C : occupant is comfortable
D : temperature is automatically controlled.

Answer 2

B: Wastes Energy

Question 3

What devices are needed to have an automatic closed loop system as applied to a control system?

A : Plug, seat and spring
B: Controller, control device and process
C : Tubing, fittings and hangers
D : Air compressor, prv and air dryer

Answer 3

B: Controller, control device and process

Question 4

The device that delivers a constant air supply to a pneumatic system is called?

A: relief valve
B: Automatic drain valve
C: control valve
D Pressure regulating valve

Answer 4

D: Pressure regulating valve

Question 5

What are three qualities that compressed air must have if it is to be used to operate pneumatic controls?

Answer 5

Clean, Dry, and oil free

Question 6

What weight of oil should always be used in a temperature control air compressor?

Answer 6

20 or 30 weight non-detergent oil.

Question 7

What is the source of energy for a pneumatic control system?

Answer 7

Compressed Air

Question 8

What is the purpose of a safety relief valve in a pneumatic control system?

Answer 8

Prevents main air supply from exceeding a preset safety limit.

Question 9

When air is removed from a controlled device, what drives the device to its normal position?

Answer 9

Spring

Question 10

What is the temperature range of a -40 degree to 160 degree transmitter?

Answer 10

200 degrees

Question 11

What is the constant supply pressure delivered to a pneumatic control system?

Answer 11

13-25 psi

Question 12

What is the pneumatic span of a transmitter regardless of the manufacturer?

Answer 12

3-15 psi

Question 13

What is an example of a control device?

A: Control valve
B: Thermostat
C: Humidistat
D: relay

Answer 13

A: Control Valve

Question 14

What is an example of a process?

A: Control Valve
B: Dehumidification
C: thermostat
D: humidistat

Answer 14

B: Dehumidification

Question 15

What is an example of a controller?

A: Control valve
B: damper actuator
C: pe relay
D: thermostat

Answer 15

D: thermostat

Question 16

What is the device called that is installed with preheat coils subjected to freezing temperatures?

Answer 16

Safety low limit

Question 17

What is the operation of modulating outside air, return air and exhaust dampers?

Answer 17

Mixed air control

Question 18

When using an external restrictor, a transmitter should be located not more than how many feet from the receiver controller?

Answer 18

1000’

Question 19

On a dual input receiver controller that is controlling a hot water system, the hot water is being reset from outside air temperature, what is the adjustment of the reset called?

Answer 19

Authority

Question 20

What type of transmitter should be used in a mixed air plenum?

Answer 20

Capillary tube

Question 21

What activates a pneumatic- electric relay?

Answer 21

Pneumatic signal

Question 22

What activates an electronic- pneumatic relay?

Answer 22

Electricity

Question 23

A direct acting thermostat would control a?

Answer 23

Normally open hot water control valve

Question 24

A reverse acting humidistat would control a:

Answer 24

Normally closed steam humidity valve

Question 25

What is the term used to describe an air handling unit that is using outside air for cooling below 75 degrees outside air temperature?

Answer 25

Economizer/ free cooling control