[D2L] 104A Intro to Controls Flashcards
What are the sub-components all types of controllers in a closed-loop control system?
1) a sensor
2) a comparator or null detector
3) a transmitter
4) all of the above
All of the above
What type of temperature controller is used in a typical residential household?
Thermostat
What are the main type of sensors used in the HVAC/R industry?
1) temperature
2) pressure
3) humidity
4) all of the above
all of the above
Where would you find an averaging element?
Across the face of a heating coil
where is the best place to mount a fast response element with regards to off cycle defrost?
evaporator
What sensor uses a thin flexible membrane that stretches across the mouth of a bell shaped container?
flexible diaphragm
What sensors react to pressure?
1) diaphragm
2) bellows
3) bourdon tube
4) all of the above
All of the above
What type of loop control is turning on a light in bedroom?
open loop
Open loop controls are automatic
False. They are manual
close loop is automatic
Thermostat Terminal
R - Main Power(24v)
G - Fan on/off (green)
Y - Cooling (blue)
W - Heat (black)
C - Common (white)
Closed loop controls are automatic
True
A motion sensor controlling a light in a room is an example of closed loop
True
What is the control agent in a residential furnace?
natural gas
If the thermostat is calling for cooling and you read 24v between R and Y which component is running?
Nothing
If 0v is measured between R and Y what components should be running?
1) Indoor Blower
2) Air conditioning
3) Heating
4) A & B
A & B