Sait Refrigeration Controls, 1St Year

Front 1

A control action that is continuously variable, the output signal changes in the same direction that the controlled or measured variable changes

Back 1

Direct-acting

Front 2

A thermostat sensing element that response to the average duct temperature

Back 2

Averaging element

Front 3

A metal element that forms from two metals that have different coefficients of thermal expansion

Back 3

Bi-metal element

Front 4

A control action that is continuously variable

Back 4

Analog

Front 5

The change in the applied signal that operates the control device while under actual conditions

Back 5

Actual spring range

Front 6

The difference between the set point and the value of the controlled variable at any instant

Back 6

Deviation

Front 7

A method of communicating in an electronic control system where the signal is a series of ones and zeros

Back 7

Digital

Front 8

A metal alloy that consists of nickel and iron

Back 8

Invar

Front 9

a mode of automatic control in which the action of the final control element is proportional to the deviation from the set point of the control medium

Back 9

Modulating control

Front 10

an electromechanical device with a terminal that connects to each end of the resistive element and a third terminal that connects to a wiper contact

Back 10

Potentiometer

Front 11

the difference between the least and greatest possible values of a controller or sensor

Back 11

Range

Front 12

The point at which the operator sets the controller

Back 12

Set point

Front 13

The difference between two limits usually expressed as a single value with a single unit

Back 13

Span

Front 14

The three main types of sensors in the HVAC industry

Back 14

Temperature sensors, pressure sensors, humidity sensors

Front 15

Four types of pressure sensors

Back 15

Flexible diaphragm, Bellows, bourdon tube, electronic pressure transducer

Front 16

Controller system modes

Back 16

On/Off, multi position, Floating, Proportional or Modulating

Front 17

Types of Heating and Cooling Systems

Back 17

Open Loop, Closed Loop

Front 18

Power Sources

Back 18

Internally powered, pneumatic, electromechanical, electronic, hybrid

Front 19

Basic Diagrams

Back 19

Connection, schematic

Front 20

Function of Delay On Make timer

Back 20

To control staging

Front 21

2 controllers a pump down system requires

Back 21

Temperature and Pressure

Front 22

Function of Delay On Break controllers

Back 22

Prevent short cycling

Front 23

What sensitivity level should a controller be set at?

Back 23

The smallest practical range

Front 24

4 primary types of controllers

Back 24

1.) Temperature

2.) Pressure

3.) Humidistat

4.) Flow

Front 25

Another term for humidistat

Back 25

Hygroscopic Controller

Front 26

Relays are rated for_________

Back 26

15A and under

Front 27

Contactors are rated for__________

Back 27

15A and greater

Front 28

Function of timers

Back 28

To introduce a pause or delay in the activation or deactivation of a circuit

Front 29

Overloads are either_____ or _____

Back 29

Line duty or pilot duty

Front 30

Function of a line duty overload

Back 30

Interrupt current to the motor directly

Front 31

Function of a pilot duty overload

Back 31

Interrupts a motor control circuit

Front 32

Function of a transformer

Back 32

Provides an increase or decrease in control circuit voltage

Front 33

Function of an Oil Failure Control (OFC)

Back 33

Protect the compressor from a lack of lubrication

Front 34

What pressures does an Oil Failure Control monitor

Back 34

Crankcase and oil pump discharge pressure

Front 35

Function of an enthalpy controller

Back 35

Measures the actual heat content of the ambient air, has a remote dry bulb sensing element and an internal hygroscopic nylon ribbon element

Front 36

In an economizer, what does the enthalpy sensor do

Back 36

Increases the efficiency of economizer-to-mechanical cooling changeover

Front 37

Time initiated, pressure-terminated defrost time clocks serve what purpose

Back 37

End a defrost cycle when the saturated suction pressure rises to a pre-set point

Front 38

Time initiated, temperature-terminated defrost time clocks serve what purpose

Back 38

Initiate a defrost cycle on a regular schedule, but allows the defrost cycle to continue until the evaporator is defrosted and the temperature reaches 45°F

Front 39

What two switches are in a standard time clock

Back 39

1.) SPDT

2.) N.C. SPST

Front 40

4 important control system characteristics

Back 40

1.) Code compliance

2.) Design

3.) Suitability

4.) Aesthetics and cost

Front 41

Analog actuator output signals

(For BAS Systems)

Back 41

1.) 0-5 VDC

2.) 0-10 VDC

3.) 4-20 mA

Front 42

Echelon Corporation developed

Back 42

Longtalk

Front 43

ASHRAE developed

Back 43

BACnet

Front 44

Modicon Corporation (now Schneider Electric) developed

Back 44

Modbus