When complete control systems become very complex, which control signal medium is preferred?

When complete control systems become very complex, which control signal medium is preferred?

a) Pneumatic
b) Electric
c) Electronic
d) Digital
e) Fibre optic





Answer: A

Dehumidification is achieved by

Dehumidification is achieved by

a) absorbing the moisture with a sponge filter
b) absorbing moisture with a chemical drying agent
c) cooling the air to a corresponding dew point temperature
d) heating air to a corresponding wet bulb temperature
e) saturating the air until the precipitation point at room temperature is reached

Answer: C

Air conditioning with respect to heating coils is achieved in which of the following ways?

Air conditioning with respect to heating coils is achieved in which of the following ways?

a) A combination of tempering control functions
b) The selected mixing of warm return air and cooler outside air
c) Selective heating by passing air through the heating coils
d) Proportioning the amount of air flow through the face damper for heat addition, or through the bypass dampers for no heat addition.
e) All of the above







Answer: E

Which of the following is not a correct method of heat regulation?

Which of the following is not a correct method of heat regulation?

a) Direct modulation of the control valve on the steam or hot water to the heating coil
b) Modulating the position of a 3-way mixing valve on the hot/cold water line into the coil
c) Modulating the relative positions of face and bypass dampers controlling air flow across the coils
d) Modulating the actuators or the steam or water supply in conjunction with the coil bypass damper
e) Modulating the valve and the face and the bypass damper 30 degrees out of phase.




Answer: E

When the outdoor air damper increases the flow of fresh air, which of the following is true?

When the outdoor air damper increases the flow of fresh air, which of the following is true?

a) The return air damper throttles up to reduce the volume of recirculated air.
b) The return air damper throttles up to increase the volume of returned air.
c) The return air damper is not affected.
d) The return air damper throttles down to reduce the volume of returned air.
e) The return air damper throttles up to increase the volume of returned air.







Answer: D

Why is the positioner for the outdoor air damper of an HVAC air handling unit interlocked with the supply fan?

Why is the positioner for the outdoor air damper of an HVAC air handling unit interlocked with the supply fan?

a. So the damper will close when the fan starts
b. So the damper will open when the fan starts
c. So the fan starts when the damper opens
d. To ensure the fan stops when the damper is fully open
e. To ensure the fan starts when the damper is fully closed







Answer: B