What important function(s) does an air receiver perform? - ANSWER Dissipates heat, dampens compressor pulsations, act as water and oil trap
On a compressed air system, a safety valve would generally be installed on the: - ANSWER Air receiver
Variable air volume system: - ANSWER Typically use ...
What important function(s) does an air receiver perform? - ANSWER Dissipates heat, dampens
compressor pulsations, act as water and oil trap
On a compressed air system, a safety valve would generally be installed on the: - ANSWER Air receiver
Variable air volume system: - ANSWER Typically use VFDs to save energy.
In figure 1.3, a full call for cooling would be at what branch pressure to the damper motor? - ANSWER 3
PSIG
A ratio relay would be used to: - ANSWER Control the sequence of actuators.
When in actuated device is said to be normally open, that means the device is open with: - ANSWER No
control pressure is applied.
In figure 1.4, the hot water valve has an 8-12 PSIG spring range, the damper motor has a 3-8 PSIG spring
range. The calibration point of the thermostat is: - ANSWER 8 PSIG
When you are setting up an instrument, you should know all of the following except:
A. Normal position of the valve or damper
B. Action and adjustment of the instrument
C. The rate of flow of the control agent
D. Spring tension or starting point of the valve or damper - ANSWER The rate of flow of the control agent
What is an example of a control with a readjusted setpoint: - ANSWER Submaster controller
, In figure 1.5, the branch pressure from the temperature controller increases in pressure as the: -
ANSWER Controlled variable decreases in temperature.
The departure of the control point from the setpoint, or the amount of that departure is described as: -
ANSWER Deviation
The action of a control that increase its branch pressure as the controlled variable increases: - ANSWER
Direct acting
In figure 1.3, maximum heating would be at what branch pressure to the damper motor? - ANSWER 13
PSIG
In figure 1.0, if the hot water control valve was N/O instead of N/C, what would the control action be?
A. Direct acting
B. Reverse acting
C. Gradual acting
D. Snap acting - ANSWER Direct acting
A three-way mixing valve: - ANSWER Has two inlets and one common outlet
What will be the typical range of a current sensor: - ANSWER 4-20 mA
In figure 1.4, with a loss of control branch pressure, this system will fail on:
A. Full cooling
B. Full heating
C. 75% cooling
D. N/A - ANSWER Full cooling
If you decrease the percentage of proportional band on a receiver controller, you would in effect: -
ANSWER Increase the PSIG/degree Fahrenheit output of the control
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