Heating Mod Week 4 Final Review

Front 1

In a hydronic heating system, the medium that circulates in the building is:

Back 1

Hot water

Front 2

If too little primary air is supplied to a gas burner the flame will:

Back 2

Turn yellow

Front 3

The body loses heat less rapidly when the relative humidity is:

Back 3

High

Front 4

In a standing pilot, the thermocouple:

Back 4

Converts the heat from the pilot into an electrical current

Front 5

The fuel most likely to be used in a residential oil furnace is:

Back 5

Grade 2

Front 6

In order for combustion to occur, there must be:

Back 6

Fuel, ignition, oxygen

Front 7

In a forced-air furnace, the air filter is normally located:

Back 7

At the return inlet

Front 8

In a pressure-type oil burner system, the fuel:

Back 8

is converted into a mist before it enters the combustion chamber

Front 9

Heat is transferred via each of the following except:

Back 9

Condensation

Front 10

The best spray angle for round or square combustion chambers is:

Back 10

70 to 90 degrees

Front 11

Which grade of fuel oil is used in vaporizing-type oil burners?

Back 11

Grade 1

Front 12

A pressure-type oil burner should burn with a _________ flame:

Back 12

Yellow

Front 13

Which condition will cause the flame to lift off of a gas burner surface?

Back 13

Too much primary air

Front 14

The hydronic heating system component that monitors water temperature in the boiler and controls the circulation of water is the:

Back 14

Aqua stat

Front 15

Name the ways hvac equipment conditions the air:

Back 15

Heating, cooling, humidification, de-humidification, air circulation, filtration

Front 16

Which of the following is true of a direct-drive fan?

Back 16

The fan speed is altered only by changing the motor speed

Front 17

In a gun-type oil burner, ignition is caused by:

Back 17

An electric spark

Front 18

A two-stage oil pump is used:

Back 18

For installations where the oil tank is below the level of the burner

Front 19

A device commonly used to check gas manifold pressure is a:

Back 19

Manometer

Front 20

One of the products of incomplete combustion is:

Back 20

Carbon monoxide

Front 21

An electric furnace

Back 21

Is powered by 220V

Front 22

What is a BTU?

Back 22

The amount of heat needed to heat 1 Lb of water 1 Degree.

Front 23

What device creates draft in a modern gas furnace?

Back 23

Induced draft motor fan

Front 24

The aquastat controls the room temperature?

Back 24

False

Front 25

One major difference between a gas-fired furnace and a packaged unit with gas heat (Gas pack) is that packaged units:

Back 25

need no vent pipe

Front 26

If a gas furnace continually trips on the temperature limit, a likely cause is a:

Back 26

dirty filter

Front 27

What method is used to prove the burner flame in a furnace with a Hot surface ignitor?

Back 27

A flame-sensing rod is located near the burner

Front 28

If reading 24V between C & W of control board indicates?

Back 28

a call for heating

Front 29

One of the purposes of using a two-speed blower is to provide:

Back 29

the different speeds needed to optimize operation of the cooling and heating functions in a dual-purpose system

Front 30

A led code of open pressure switch fault is an indication of all of the following problems EXCEPT:

Back 30

Bad HSI

Front 31

A pilotless system is one in which:

Back 31

a direct spark ignitor or HSI is used

Front 32

Which of the following is not part of the operating sequence of a natural-draft furnace?

Back 32

The pressure switch proves that the Induced-draft fan is on

Front 33

If reading 24V between R & W of control board indicates:

Back 33

no call for heating

Front 34

Each of these is a device for igniting the gas at the gas burners, except the:

Back 34

thermocouple

Front 35

If you read voltage at the primary side of a transformer but no voltage on the secondary side, this indicates:

Back 35

a bad transformer

Front 36

A device made up of 2 unlike metals that generates electricity when there is a difference in temperature from one end to the other:

Back 36

Thermocouple

Front 37

A gas control containing 2 gas valves in series. If one fails, the other is available to shut off the gas when needed:

Back 37

Redundant gas valve

Front 38

A switch that is activated by a blade that reacts to the flow of water or air:

Back 38

Vane switch

Front 39

A gas valve body containing 2 separate valves that supply fuel gas to the burners based on the amount of heat demand from the t-stat:

Back 39

Two-stage gas valve

Front 40

A gas valve provides precise control of burner capacity by changing the flow of gas to the burners in small increments:

Back 40

Modulating gas valve

Front 41

A process in which exposure of a sensing rod to a flame produces a tiny current that can be sensed and used to control the gas valve:

Back 41

Flame rectification

Front 42

First sequence of operation (Gas furnace induced draft with direct ignition)

Back 42

Call for heat / 24V

Front 43

Second sequence of operation (Gas furnace induced draft with direct ignition)

Back 43

Induced draft motor energizes / 120V

Front 44

Third sequence of operation (Gas furnace induced draft with direct ignition)

Back 44

Vacuum switch energizes / 24V

Front 45

Fourth sequence of operation (Gas furnace induced draft with direct ignition)

Back 45

HSI Hot surface ignitor energizes / 120V

Front 46

Fifth sequence of operation (Gas furnace induced draft with direct ignition)

Back 46

Gas burner energizes / 24V

Front 47

Sixth sequence of operation (Gas furnace induced draft with direct ignition)

Back 47

Flame sensor senses flame rectification / DC Millivolts

Front 48

Seventh sequence of operation (Gas furnace induced draft with direct ignition)

Back 48

Blower motor starts / 120V

Front 49

Refrigeration Cycle Step 1

Back 49

Starting at the compressor inside the condenser, the vapors compress from a low pressure, low temperature vapor exiting thru the Discharge line as a High temperature, High pressure vapor.

Front 50

Refrigeration Cycle Step 2

Back 50

The High temperature, High pressure vapors continue thru as the air blown across the coils rejects heat at the condenser coils where half way thru the vapor changes to a Sub cooled liquid and exits the condenser thru the liquid line.

Front 51

Refrigeration Cycle Step 3

Back 51

The sub cooled High pressure liquid continues thru the liquid line to the Metering Device where it changes from a High pressure liquid to a Low pressure, Low temperature 75% Vapor, 25% liquid passing thru the capillary tubes into the Evaporator coil.

Front 52

Refrigeration Cycle Step 4

Back 52

As this mixture enters the Evaporator coil about half way thru as the warmer air blown across the coils absorbs heat the mixture changes to a Vapor or Superheated Gas and then it exits the Evaporator thru the Suction line maintaining the Evaporators 40 degree optimized temperature and heads back outside back to the suction side of the compressor where the cycle starts all over again.