Gas Heating

Question 1

A limit is stamped 190-50 what does it reset at?

Answer 1

140

Question 2

The most common furnace used in a crawl space is?

Answer 2

Horizontal

Question 3

A limits is stamped 190-50. This means it open at?

Answer 3

190

Question 4

High limits are usually what voltage?

Answer 4

24

Question 5

The btu content of one cubic foot of natural gas is?

Answer 5

1050

Question 6

How many millivolts DC does a thermocouple generate?

Answer 6

75

Question 7

In order to use a fan limit control with both high and low voltage what must be done first?

Answer 7

Cut the jumper

Question 8

High efficiency furnaces have how many heat exchangers?

Answer 8

2

Question 9

Going counter clockwise on a fan limit control, the first pin on it does what?

Answer 9

Fan on

Question 10

A fan limit with resister has a coil wired to what terminal

Answer 10

G

Question 11

What terminal is for power on the thermostat?

Answer 11

R

Question 12

The burner that can only be used on induced draft furnaces is?

Answer 12

inshot

Question 13

Air going into the blower is called?

Answer 13

Return Air

Question 14

What does deltaT stand for?

Answer 14

Temperature difference

Question 15

Which valve uses a magnetic coil to pull the valve open?

Answer 15

solenoid

Question 16

How do high effiency furnaces get rid of condensate?

Answer 16

rifling tubes

Question 17

A good burning flame is what color?

Answer 17

Blue

Question 18

A yellow flame means what?

Answer 18

dirt or debris

Question 19

A fan limit control is what type of fan delay?

Answer 19

Temp on- Temp off

Question 20

Air leaving the heat exchanger is called what?

Answer 20

Supply air.

Question 21

Flame rollouts must be what?

Answer 21

Manual reset

Question 22

We delay the blower turning on for what reason?

Answer 22

Prevent blowing cold air.

Question 23

Ignition that lights the burners without a pilot is called what?

Answer 23

Direct burner ignition

Question 24

Primary air and secondary air together is called what?

Answer 24

Combustion air.

Question 25

What is the most common voltage our gas valves run off of?

Answer 25

24V

Question 26

Propane pressure is usually set to how many inches of WC.

Answer 26

10-11

Question 27

What part transfers heat from the flue gases to the conditioned space?

Answer 27

Heat exchanger

Question 28

Solenoid vales close how?

Answer 28

Spring loaded

Question 29

Too low of air flow could cause what?

Answer 29

Corrosion, cracked heat exchanger, blower malfunction

Question 30

How many millivolts DC do thermopiles generate?

Answer 30

750mv

Question 31

What is the most common cause of flame impingement?

Answer 31

misaligned burners

Question 32

We delay turning the blower off for what reason?

Answer 32

Cool the heat exchanger down.

Question 33

Spark ignition that lights the burners without a pilot is called what?

Answer 33

Direct burner ignition.

Question 34

A board delay is what type of fan delay?

Answer 34

Time on- Time off

Question 35

Thermocouples should generate how many millivolts DC.

Answer 35

75

Question 36

Some heat exchangers are coated in aluminum, glass, or ceramic to minimize what?

Answer 36

Corrosion

Question 37

Inducer motors operate on what voltage?

Answer 37

120VAC

Question 38

What terminal is used for heating on the thermostat?

Answer 38

W

Question 39

Why do we not want flue gases in our home?

Answer 39

carbon monoxide, deadly, not good for you

Question 40

The part that is responsible for pushing the flue gases out of our home is called?

Answer 40

Inducer motor

Question 41

What system has a pilot burning all the time?

Answer 41

Standing pilot

Question 42

Going counter clockwise the second pin on a fan limit is what?

Answer 42

High limit

Question 43

A furnace that has supply and return out the top is called what?

Answer 43

Lowboy

Question 44

What part ensure the inducer is doing its job correctly?

Answer 44

Pressure switch

Question 45

Most HSI ignitors operate off of what voltage?

Answer 45

120V

Question 46

Limits are often wired in series with what part?

Answer 46

Gas Valve

Question 47

Give me an acceptable setting for a high limit?

Answer 47

190-200

Question 48

What part leaves the gas valve?

Answer 48

Manifold

Question 49

Which device stops your furnace if the heat exchanger gets to hot?

Answer 49

High limit

Question 50

Two main factors influence temperature difference, give me one?

Answer 50

Blower speed

Question 51

What part do thermopile systems often not require?

Answer 51

Transformer

Question 52

The most common example of a bimetallic safety switch is what?

Answer 52

3 wire pilot

Question 53

Gases leaving the heat exchanger and taken outside to be released are called what?

Answer 53

Flue gases