206-Components

Question 1

What five devices are used to measure changes in temperature

Answer 1

Bimetal, fluid expansion, thermocouple, thermistor, hydraulic

Question 2

What four things do you have to know to buy a replacement control transformer

Answer 2

VA rating, size, primary voltage, secondary voltage

Question 3

What are the electrical characteristics of most residential transformers

Answer 3

Electrical devices that produce electrical current in a secondary circuit through electromagnetic induction

Question 4

What are the three types of mounts for transformers

Answer 4

Foot, hub, plate

Question 5

What does a fan control center consist of

Answer 5

Transformer, indoor fan relay, low-voltage terminals

Question 6

When would you need to phase 2 transformers

Answer 6

When you have a transformer in the furnace and a separate transformer in the AC system

Question 7

What is the purpose of the heat anticipator

Answer 7

To prevent or reduce overshooting the temperature setting

Question 8

When is the heat anticipator in the circuit

Answer 8

While the system is an operation, and it energizes anytime the thermostat Contacts close

Question 9

What current is used to set the heat anticipator

Answer 9

Set the anticipator to the amp draw of the heat controller

Question 10

What three things can be used to find the heat anticipator setting

Answer 10

Ammeter with jumper wire, Digital milliamp meter, manufacturers literature

Question 11

On new digital thermostat is what takes the place of the heat anticipator

Answer 11

Cycle rate settings

Question 12

What is the purpose of a cooling anticipator

Answer 12

To turn the system on ahead of time, so it doesn’t get hot in the conditioned space before the unit turns on

Question 13

When is the cooling anticipator in the circuit

Answer 13

When the system is in the off cycle

Question 14

What are the differences between line voltage and low-voltage thermostats

Answer 14

Line voltage operates with 120 V and above, low-voltage operates with 24 V

Question 15

What are some applications of line voltage thermostat’s

Answer 15

Refrigeration systems, gas-fired unit heater, electric baseboard heaters, PT AC’s, ventilation fans

Question 16

What are two types of motor protectors

Answer 16

Fuses, circuit breaker’s

Question 17

How will a compressor ohm out from common to run when the internal overload opens

Answer 17

OL

Question 18

How will a compressor ohm out from common to start when the internal overload opens

Answer 18

OL

Question 19

How will a compressor ohm out from Run to start when the internal overload opens

Answer 19

Will read resistance

Question 20

What should you do if the internal overload opens

Answer 20

Wait until the compressor cools down, or seal up electrical components and run water over the compressor to cool it down

Question 21

Gift for uses of a pressure switch that brakes on a fall

Answer 21

Condenser fan cycle control, low pressure cut out control, low charge protection, cycle compressor on a pump down control system

Question 22

List five reasons a high-pressure switch with open

Answer 22

Dirty condenser coil, fan out, fanblades wrong direction, overcharge, high heat load

Question 23

What are the two connections of an oil pressure switch

Answer 23

Oil pump outlet, crankcase

Question 24

What are the three uses of air pressure switches

Answer 24

Ice build up on the outdoor coil of a heat pump, ensure that the blower is passing air through the duct, prove combustion blower motor is operating

Question 25

What is the purpose of a programmable thermostat

Answer 25

Set up days of the week, times for running, schedule the operation of the systems unit

Question 26

What maintenance should be done on thermostats

Answer 26

Change batteries if needed, check heat and cooling anticipator

Question 27

Why are staging thermostats used

Answer 27

Stage on compressor or heat strips depending on the heat or cooling load (save money because of changes in building a load)

Question 28

Why are two stage heating thermostats used with heat pumps

Answer 28

Heat pumps aren’t efficient below a certain temperature so you need a two stage heating thermostat to bring on either strips or furnace to make up for the heat pump

Question 29

What are the two differences between a relay and a contactor

Answer 29

Relay handle small loads and is a throwaway, contactor handles larger loads and can be rebuilt

Question 30

A relay or contactor consists of what three parts

Answer 30

Coil, contacts, terminals

Question 31

What do the terms normally open and normally closed mean in reference to switches

Answer 31

When do you energized it will either be normally open or normally closed

Question 32

What four things do you have to know to buy a replacement contactor

Answer 32

Voltage rating, amp rating, coil voltage, mounting arrangement

Question 33

What is the difference between a contactor and a starter

Answer 33

Contactor has no overload protection, starter has overload protection built in

Question 34

How are contacts cleaned

Answer 34

They may be buffed or cleaned with a file or sandpaper, this is a temporary solution

Question 35

How can dirty contacts be detected with a voltmeter

Answer 35

You can use a voltmeter to check resistance across a set of contacts on your full load. When laser place on each side of a set of contacts in a measurable voltage exists there is resistance in the contacts. When the contacts are new and have no resistance no voltage should be read

Question 36

What is another good way to check contacts

Answer 36

Visual inspection looking for pitted contacts

Question 37

What are three types of motor protection

Answer 37

Internal external magnetic

Question 38

What is another name for a magnetic overload

Answer 38

Heinemann overload, Circuit overloads protection