Electronic Ignition 4th year

Question 1

What is important for the Sheet Metal Worker to understand effectively when
troubleshooting HVAC appliances?

Answer 1

By understanding these factors, sheet metal workers can troubleshoot appliances more effectively, ensuring that systems are repaired correctly and functioning safely

Question 2

What are the four different ways that an electronic ignition system can be configured for a
heating appliance?

Answer 2

1. Hot Surface Ignition:
2. Direct Spark Ignition:
3. Standing Pilot Ignition:
4. Intermittent Pilot Ignition:

Question 3

Describe how the ignition process for an interrupted Pilot Ignition System works.

Answer 3

. It works by using an electrical spark to ignite a small flame, called a pilot light, which in turn ignites the main burner.

Question 4

Describe how the ignition process for an Intermittent Pilot Ignition system works.

Answer 4

It works by using an electrical spark to ignite a small flame, called a pilot light, which in turn ignites the main burner.
The only difference is that the pilot is not extinguished after ignition of the main burner

Question 5

On the occasion that a smart valve is used in a gas heating appliance, what is the voltage,
ignition type, and what is lit first?

Answer 5

1. Voltage: Smart valves typically operate on 24-volt AC power.
2. Ignition type: hot surface ignition,direct spark ignition and intermittent pilot ignition
3. What is lit first: In smart valves with intermittent pilot ignition, the pilot light is the first to be lit.

Question 6

What device controls the ignition process and also senses that there is flame through the
flame rod?

Answer 6

is called a flame sensor, also known as a flame rectification sensor

Question 7

What is the recommended spark gap distance?

Answer 7

The recommended spark gap is 1/8”

Question 8

About how many volts are sent through the spark igniter?

Answer 8

24- volts

Question 9

What are some of the disadvantages for using a silicon carbide igniter as part of the hot
surface igniter?

Answer 9

1. Fragility: Silicon carbide igniters can be brittle and can easily break or crack. They are also sensitive to physical damage from handling during installation or maintenance, which can shorten their lifespan.

Question 10

Describe how the ignition process for a Direct –Spark Ignition System works.

Answer 10

It lights the main burner directly,using spark as in the intermittent pilot ignition.

Question 11

What does the external fuse protect inside a furnace?

Answer 11

The external fuse in a furnace is designed to protect the furnace’s electrical components, including the control board, blower motor, and gas valve, from electrical current surges or shorts.

Question 12

What voltage does the hot surface igniter use?

Answer 12

115-volt AC

Question 13

How long does the hot surface igniter take for it to heat up fully?

Answer 13

17-34 seconds

Question 14

What is the approximate temperature of the hot surface igniter when energized?

Answer 14

approximately 2600 f (1427c)

Question 15

Why should you not touch the hot surface igniter itself with your fingers (silicon carbide)?

Answer 15

is very brittle, it will burn out.

Question 16

When the flame rod needs to be cleaned, what should be used to clean it?

Answer 16

use scotch brite pads or 000 steel wool only.

Question 17

If an abrasive material is used for cleaning of the flame rod then what could happen to the
ratio?

Answer 17

will cause a change and the system will not prove flame.

Question 18

What is the flame sensor to ground ratio?

Answer 18

at least 4:1

Question 19

Why is the ratio needed for flame rectification?

Answer 19

to best operate, the larger the ratio of ground area to flame rod area the greater the rectified current.

Question 20

List the two different principles in a flame detection system.
___________________________________________________________________________
___________________________________________________________________________

Question 21

Which flame detection system is not used today?
___________________________________________________________________________

Question 22

List the parts of the circuit required for flame rectification.
___________________________________________________________________________
__________________________________________________________________________

Question 23

What ionizes the current?
___________________________________________________________________________

Question 24

What is usually good knowledge when servicing a furnace or heating appliance?
___________________________________________________________________________

Question 25

What is the first thing that needs to happen to start the sequence of operation? ___________________________________________________________________________

Question 26

Which terminals are used for the call for heat signal? ___________________________________________________________________________

Question 27

What are some of the other names that can be used for, “Inducer fan”? ___________________________________________________________________________ ___________________________________________________________________________

Question 28

What ensures that the inducer fan is in proper operation before the furnace is able to continue its heating process? __________________________________________________________________________

Question 29

What does the module do when it completes the safe- start check? ___________________________________________________________________________ __________________________________________________________________________

Question 30

Once the pilot flame is present, what does the module do next? ___________________________________________________________________________ __________________________________________________________________________

Question 31

Describe post purge cycle. ___________________________________________________________________________ __________________________________________________________________________

Question 32

When the furnace has completed the heating cycle, what happens next? __________________________________________________________________________

Question 33

When the ignition system fails to ignite properly, the module will wait to clear the combustion chamber of unburned gas and re-try. This is called: __________________________________________________________________________

Question 34

What are some ways to reset the lockout for trial for ignition? __________________________________________________________________________

Question 35

List the two different types of wiring diagrams that are usually available in HVAC equipment.

Answer 35

pictorial (connection), schematic (ladder)

Question 36

Are there any standards set for the electrical symbols and abbreviations in wiring diagrams? _________________________________________________________________________

Question 37

Which type of wiring diagram uses wire colors in its schematic? _______________________________________________________________

Answer 37

connection diagram

Question 38

Do the wiring diagrams show with power or no power? ______________________________________________________________________

Question 39

What is the benefit of using a ladder diagram over the connection diagram? ________________________________________________________________________

Answer 39

it is most helpful in determining the sequences of operation of the appliance for the purposes of troubleshooting.

Question 40

When working with a thermostat, there are the following terminals: R,W,Y,G,C,W1,W2. Identify what each letter is used for. ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ __________________________________________________________________________

Question 41

What does IDM stand for?

Answer 41

induced draft motor

Question 42

What does PRS stand for?

Answer 42

pressure switch

Question 43

What voltage is at the “R” terminal when energized?

Answer 43

24 vac

Question 44

About how long does it take for the hot surface igniter to warm up?

Answer 44

17-34 seconds

Question 45

What is the “Spare” terminal used for? ________________

Question 46

What is the average time allowed for the Post Purge? ___

Answer 46

30 seconds

Question 47

When replacing a fuse in the furnace, it is best to replace it with:

Answer 47

the right size

Question 48

Replacing electrical components in the furnace must be installed as per the manufacturer’s specifications. (True/False)

Answer 48

true

Question 49

What are the fan speeds adjusted to when starting up the furnace? _________________________________________________________________

Question 50

What does DIP stand for?

Answer 50

Dual in-line packaged

Question 51

What two methods are normally used to change the fan off delay in the furnace?

Answer 51

the electronic control board incorporates small DIP switches or there could be a jumper plug that can be adjusted for different fan off delay setting.

Question 52

Do all ignition control modules (gas fired furnaces) come with Light –emitting diodes?

Answer 52

yes

Question 53

What is good about the LED codes in a furnace?

Answer 53

good for troubleshooting, diagnose normal condition or a faulty one,