Pneumatics Flashcards
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
D: unreliable service
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.
B: Wastes Energy
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
B: Controller, control device and process
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
D: Pressure regulating valve
What are three qualities that compressed air must have if it is to be used to operate pneumatic controls?
Clean, Dry, and oil free
What weight of oil should always be used in a temperature control air compressor?
20 or 30 weight non-detergent oil.
What is the source of energy for a pneumatic control system?
Compressed Air
What is the purpose of a safety relief valve in a pneumatic control system?
Prevents main air supply from exceeding a preset safety limit.
When air is removed from a controlled device, what drives the device to its normal position?
Spring
What is the temperature range of a -40 degree to 160 degree transmitter?
200 degrees
What is the constant supply pressure delivered to a pneumatic control system?
13-25 psi
What is the pneumatic span of a transmitter regardless of the manufacturer?
3-15 psi
What is an example of a control device?
A: Control valve
B: Thermostat
C: Humidistat
D: relay
A: Control Valve
What is an example of a process?
A: Control Valve
B: Dehumidification
C: thermostat
D: humidistat
B: Dehumidification
What is an example of a controller?
A: Control valve
B: damper actuator
C: pe relay
D: thermostat
D: thermostat
What is the device called that is installed with preheat coils subjected to freezing temperatures?
Safety low limit
What is the operation of modulating outside air, return air and exhaust dampers?
Mixed air control
When using an external restrictor, a transmitter should be located not more than how many feet from the receiver controller?
1000’
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?
Authority
What type of transmitter should be used in a mixed air plenum?
Capillary tube
What activates a pneumatic- electric relay?
Pneumatic signal
What activates an electronic- pneumatic relay?
Electricity
A direct acting thermostat would control a?
Normally open hot water control valve
A reverse acting humidistat would control a:
Normally closed steam humidity valve
What is the term used to describe an air handling unit that is using outside air for cooling below 75 degrees outside air temperature?
Economizer/ free cooling control
