Hvac

Question 1

React to heat by changing resistance, often to modify an electrical signal being measured by an instrument

Answer 1

Thermistor

Question 2

React to heat by producing a voltage that generates a current in a completed circuit

Answer 2

Thermocouple

Question 3

React to heat by changing pressure, usually with diaphragm or bellows.

Answer 3

Sensing bulb

Question 4

A circuit that responds to change in the signal from sensors and issues signals to devices

Answer 4

Controller

Question 5

A device that change an input energy into mechanical motion

Answer 5

Actuator

Question 6

A device commonly use to start and stop another operation of another system component such as motor

Answer 6

Relay

Question 7

Relay that uses electronic devices for switching

Answer 7

Solid state

Question 8

Heavy duty relay with built-in overload protection

Answer 8

Motor starter

Question 9

Heavy duty relay with parts that can be replaced

Answer 9

Contactor

Question 10

Whose operation is based on CEMF

Answer 10

Potential relay

Question 11

The present condition as it is measured

Answer 11

Control point

Question 12

The difference between the desired and present condition

Answer 12

Offset

Question 13

The desired conditions

Answer 13

Set point

Question 14

This motor is not commonly found in AC units, it has a centrifugal switch or start relay to remove the start capacitor and start winding from the circuitry once it reaches 75% of it rate RPM’s

Answer 14

CSIR

Question 15

This motor is basically a PSC motor with a start capacitor and relay to drop out the start cap. It has a high starting torque

Answer 15

CSCR

Question 16

This motor has a run capacitor wire in series with start winding. Start relay or centrifugal is needed, the run capacitor reduce the current flow through the start winding so it can stay in the circuit

Answer 16

PSC motor

Question 17

This motor has a run and start winding and start winding must be protected. It has a low running and starting torque

Answer 17

Split phase motor

Question 18

This motor is single speed or multi speed motor. It has low running and starting torque and has a run winding only

Answer 18

Shaded pole motor

Question 19

This compressor is a piston type compressor use in domestic commercial system

Answer 19

Reciprocating compressor

Question 20

This compressor is use in large commercial refrigeration systems over 50 tons. It use impeller or wheels and has no valve or piston and operated at high speed

Answer 20

Centrifugal compressor

Question 21

This compressor is the newest type of compressor and has no intake or discharge valve except a check valve on the discharge. It has very little wear and tear because it has so few moving parts

Answer 21

Scroll compressor

Question 22

This compressor is used on large chill water systems 20 tons and up. It uses to spacing between the lobes of screws to compres the refrigerant and will operate smoothly even when it’s capacity is reduced to as low as 10%

Answer 22

Screw compressor

Question 23

This compressor is small and light weight and uses blades or vane to move the refrigerant

Answer 23

Rotary compressor