[D2L] 104A Intro to Controls

Question 1

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

Answer 1

All of the above

Question 2

What type of temperature controller is used in a typical residential household?

Answer 2

Thermostat

Question 3

What are the main type of sensors used in the HVAC/R industry?

1) temperature
2) pressure
3) humidity
4) all of the above

Answer 3

all of the above

Question 4

Where would you find an averaging element?

Answer 4

Across the face of a heating coil

Question 5

where is the best place to mount a fast response element with regards to off cycle defrost?

Answer 5

evaporator

Question 6

What sensor uses a thin flexible membrane that stretches across the mouth of a bell shaped container?

Answer 6

flexible diaphragm

Question 7

What sensors react to pressure?

1) diaphragm
2) bellows
3) bourdon tube
4) all of the above

Answer 7

All of the above

Question 8

What type of loop control is turning on a light in bedroom?

Answer 8

open loop

Question 9

Open loop controls are automatic

Answer 9

False. They are manual
close loop is automatic

Question 10

Thermostat Terminal

Answer 10

R - Main Power(24v)
G - Fan on/off (green)
Y - Cooling (blue)
W - Heat (black)
C - Common (white)

Question 11

Closed loop controls are automatic

Answer 11

True

Question 12

A motion sensor controlling a light in a room is an example of closed loop

Answer 12

True

Question 13

What is the control agent in a residential furnace?

Answer 13

natural gas

Question 14

If the thermostat is calling for cooling and you read 24v between R and Y which component is running?

Answer 14

Nothing

Question 15

If 0v is measured between R and Y what components should be running?

1) Indoor Blower
2) Air conditioning
3) Heating
4) A & B

Answer 15

A & B