Controls (Unit 5)

Front 1

A sensor, controller and controlled device to control variable value describes:

Back 1

A control system

Front 2

The control systems most likely to be found in a building may be:

Back 2

Pneumatic or DDC

Front 3

A closed loop control system is controlled by:

Back 3

A self-containrd control system

Front 4

An example of _______________ is when a controller cycles a chilled water pump ON when the outside temp is above 65°F but sends NO signal back showing the status of the pump.

Back 4

Open loop control

Front 5

Valves and dampers are examples of:

Back 5

Controlled devices (or end devices)

Front 6

A _______ control is a control in which the controlled device is positioned (modulated) in direct response to the amount of offset in the system.

Back 6

Proportional (analog)

Front 7

The desired value to be maintained by a control system is the:

Back 7

Setpoint

Front 8

_______ is the difference between a control point and a setpoint.

Back 8

Offset

Front 9

In a hybrid control system, _______ are used as a common interface between different control systems technologies.

Back 9

Transducers

Front 10

A drawing of a mechanical system that illustrates actual controls and piping between devices is called:

Back 10

A control drawing

Front 11

In a hot water tank, electric elements heat up the surrounding water until the hot water rises, which is then replaced by cooler water. This is and example of:

Back 11

Convection

Front 12

The ____________ is when the heat losses through a building are the same as the amount of heat provided by the heat pump.

Back 12

Balance point

Front 13

Comfort is usually attained at normal cooling and heating temperatures with humidity levels of about:

Back 13

50%

Front 14

The outside air dry-bulb temp of _______ is common for outside air economizer use.

Back 14

45°-65°F

Front 15

What is the primary cause of excessively hot or cold temperature complaints?

Back 15

Incorrect setpoint

Front 16

A compressor, dryer, filter, PRV and relief valve are all elements found in:

Back 16

An air supply system

Front 17

The ______________ attached to the receiver starts and stops the air compressor and enables the compressed air station to deliver the correct system air pressure

Back 17

Pressure switch

Front 18

Number of starts per hour of the air compressor should not exceed;

Back 18

The manufacturer recommended limit

Front 19

______ in a compressed air tank causes controls and air compressor problems, receiver to rust and should be drained.

Back 19

Moisture

Front 20

An excessive amount of lubricating oil leaking by the Piston rings and carried into the compressed air system is called:

Back 20

Carry over

Front 21

The ability of a liquid to resist flow is called:

Back 21

Viscosity

Front 22

A _____ compressor uses interlocking rotors to compress air.

Back 22

Screw

Front 23

Dampers that regular air flow, calves that regulate water or steam, and refrigeration compressors that deliver cooling are examples of:

Back 23

Controlled devices

Front 24

__________ dampers have a nonlinear flow characteristic and are widely used on VAV terminal boxes.

Back 24

Round blade

Front 25

What is the normal position of a controlled device?

Back 25

The position of the device when no energy is applied

Front 26

______________ is when control pressure is required to move the end device from fully open to fully closed or vise versa.

Back 26

Spring range pressure

Front 27

_______ dampers regulates the air flow in carrying ducts.

Back 27

Opposed or parallel

Front 28

_______ is the most common blade damper used in HVAC systems.

Back 28

Parallel

Front 29

A _______ valve has one inlet and two outlets.

Back 29

Diverting

Front 30

A _______ valve has two inlets and one outles.

Back 30

Mixing

Front 31

____________ control the flow of fluids (water or steam) in an HVAC system.

Back 31

Control valves

Front 32

__________ thermostats increase in branch line pressure as temperature increases.

Back 32

Direct acting

Front 33

__________ thermostats decrease in branch line pressure as the temp increases.

Back 33

Reverse acting

Front 34

Heating/cooling or day/night thermostats are:

Back 34

Dual pressure thermostats

Front 35

The range between two temperatures in which no heating or cooling takes place is called:

Back 35

Dead band

Front 36

The _______________ in a pneumatic humidistat accepts moisture from, or rejects moisture to, the surrounding air.

Back 36

Hygroscopic element

Front 37

The ____________ senses the room temp and responds accordingly.

Back 37

Bimetal element

Front 38

The small heater in a thermostat that causes an HVAC unit to stop heating before normal shut down to avoid overshooting is called:

Back 38

A heating anticipator

Front 39

A device that sends signal to controller is:

Back 39

A transmitter

Front 40

All pneumatic transmitters produce a _____ to _____ output signal.

Back 40

3psig to 15psig

Front 41

Most transmitters are _____ pipe, _____ volume devices.

Back 41

One-pipe, low volume

Front 42

A two-piped transmitter uses:

Back 42

Full volume of the compressed air available

Front 43

_______ are accurate when shipped from the factory.

Back 43

Transmitters

Front 44

A device that senses total pressure and static pressure in a duct is:

Back 44

A pilot tube

Front 45

A device that allows an air pressure signal to energize or de-energize an electrical device such as a fan, pump, compressor, or electric heating devices is:

Back 45

A pneumatic/electric switch (p/e switch)

Front 46

A device that has a capillary tube sensing element and is used to protect against damage due to freezing conditions is called:

Back 46

A low temp cutout control (freeze stat)

Front 47

The _______ sends a signal to the controlled device (end device).

Back 47

Controller

Front 48

Excessive actuator hunting or cycling is caused by:

Back 48

A throttling range that is too small

Front 49

_________________ is capable of resetting the setpoint.

Back 49

A dual input receiver controller

Front 50

__________ is designed for basic zone control and uses a standard wall-mount temp sensor.

Back 50

A unitary controller

Front 51

Typically a variable air volume (VAV) air handling unit controls building space by changing:

Back 51

The volume of air, not the temperature

Front 52

Most VAV air handling units maintain a constant static pressure, and duct static pressure of _____.

Back 52

1"wc

Front 53

Most VAV air handling units maintain a constant discharge air temp of:

Back 53

55°F

Front 54

The constant volume system provides constant air flow by:

Back 54

Varying the temperature

Front 55

Low voltage is voltage at:

Back 55

30 VAC or less

Front 56

A device that changes AC voltage into DC voltage is:

Back 56

A rectifier

Front 57

An electronic control system has a power supply of:

Back 57

24 VDC or less

Front 58

The most common building automation system controller power supply is:

Back 58

120 VAC to 24 VAC step down transformer

Front 59

DDC systems may be part of a larger system called:

Back 59

A building automation system

Front 60

HVACequiptment, lighting, security, and other essential functions are controlled by:

Back 60

The building automation system

Front 61

Packaged units, VAVs, hot water, and chilled water are:

Back 61

Direct digital controls

Front 62

Features of ____________ may be economizer lockout control, lead/lag control, high/low signal select, and averaging control.

Back 62

Direct digital control

Front 63

DDC controllers are often reffered to as:

Back 63

Modules or panels

Front 64

Appliaction-specific controllers are designed to control:

Back 64

Only one type of HVAC system

Front 65

______________ are fully programmable, can be used in most HVAC systems and have fixed number of inputs and outputs.

Back 65

Universal input-output controllers

Front 66

Inputs and outputs connected to DDC controllers are called:

Back 66

Points

Front 67

__________ are digital inputs used to obtain the operational status of pumps, fans, compressors, and lighting.

Back 67

Current-sensing relays

Front 68

A configuration in which multiple controllers are connected in series is called:

Back 68

A daisy chain

Front 69

A device that has a unique address and is attached to a network is a:

Back 69

Node

Front 70

A network switch board that allows a number of nodes to communicate with each other is called:

Back 70

A concentrator

Front 71

Control algorithm that automatically adjusts it's response time based on environmental conditions is called:

Back 71

Adaptive control algorithm

Front 72

What follows commands sent to it from the CPU of a central DDC system?

Back 72

Field interface devices

Front 73

______________ may be reffered to as data gathering panels (DGPs) or data acquisition panels (DAPs)

Back 73

Field interface devices

Front 74

The building automation system is commonly reffered to as:

Back 74

The BMS

Front 75

An analog input signal:

Back 75

Leaves the sensor and travels to the controller

Front 76

An analog/digital output signal:

Back 76

Leave the controller and travels to the end device

Front 77

A proportional signal that controls a modulating device would use a/an _______ signal.

Back 77

Analog

Front 78

A two-position signal that is sent to the controller would use a/an _______ signal

Back 78

Digital

Front 79

Temperature, pressure and humidity sensors are examples of:

Back 79

Analog inputs

Front 80

Dampers, valves, VFDs and transducers are examples of:

Back 80

Analog outputs

Front 81

The control of a low voltage coil of a relay is an example of:

Back 81

Digital output

Front 82

The process of adding the individual input and output points to the data base of human-computer interface is called:

Back 82

Point mapping

Front 83

The total amount of electricity used during a billing period is:

Back 83

Electrical consumption

Front 84

The highest amount of electricity used during a specific period of time is called:

Back 84

Electrical demand

Front 85

An electric load that has been turned OFF by an electrical demand supervisory control strategy is:

Back 85

A shed load

Front 86

The amount of money a utility is permitted to charge to reflect the constantly changing cost of energy is:

Back 86

The fuel recovery rate

Front 87

Indication of abnormal conditions (alarms), providing information regarding energy consumption and equipment maintnence may be found:

Back 87

In the BAS (building automation system)

Front 88

Duty cycling, optimization, and load shedding are examples of:

Back 88

Supervisory control strategies (energy consuming functions)

Front 89

The primary desktop PC used to communicate with a building automation system is commonly referred to as the:

Back 89

Front end

Front 90

The amount of change required in a variable for the alarm to return to normal after it has been in alarm status is called:

Back 90

An alarm differential