Electronic Ignition 4th year Flashcards
What is important for the Sheet Metal Worker to understand effectively when
troubleshooting HVAC appliances?
By understanding these factors, sheet metal workers can troubleshoot appliances more effectively, ensuring that systems are repaired correctly and functioning safely
What are the four different ways that an electronic ignition system can be configured for a
heating appliance?
- Hot Surface Ignition:
- Direct Spark Ignition:
- Standing Pilot Ignition:
- Intermittent Pilot Ignition:
Describe how the ignition process for an interrupted Pilot Ignition System works.
. It works by using an electrical spark to ignite a small flame, called a pilot light, which in turn ignites the main burner.
Describe how the ignition process for an Intermittent Pilot Ignition system works.
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
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?
- Voltage: Smart valves typically operate on 24-volt AC power.
- Ignition type: hot surface ignition,direct spark ignition and intermittent pilot ignition
- What is lit first: In smart valves with intermittent pilot ignition, the pilot light is the first to be lit.
What device controls the ignition process and also senses that there is flame through the
flame rod?
is called a flame sensor, also known as a flame rectification sensor
What is the recommended spark gap distance?
The recommended spark gap is 1/8”
About how many volts are sent through the spark igniter?
24- volts
What are some of the disadvantages for using a silicon carbide igniter as part of the hot
surface igniter?
- 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.
Describe how the ignition process for a Direct –Spark Ignition System works.
It lights the main burner directly,using spark as in the intermittent pilot ignition.
What does the external fuse protect inside a furnace?
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.
What voltage does the hot surface igniter use?
115-volt AC
How long does the hot surface igniter take for it to heat up fully?
17-34 seconds
What is the approximate temperature of the hot surface igniter when energized?
approximately 2600 f (1427c)
Why should you not touch the hot surface igniter itself with your fingers (silicon carbide)?
is very brittle, it will burn out.
When the flame rod needs to be cleaned, what should be used to clean it?
use scotch brite pads or 000 steel wool only.
If an abrasive material is used for cleaning of the flame rod then what could happen to the
ratio?
will cause a change and the system will not prove flame.
What is the flame sensor to ground ratio?
at least 4:1
Why is the ratio needed for flame rectification?
to best operate, the larger the ratio of ground area to flame rod area the greater the rectified current.
List the two different principles in a flame detection system.
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Which flame detection system is not used today?
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List the parts of the circuit required for flame rectification.
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What ionizes the current?
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What is usually good knowledge when servicing a furnace or heating appliance?
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What is the first thing that needs to happen to start the sequence of operation?
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Which terminals are used for the call for heat signal?
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What are some of the other names that can be used for, “Inducer fan”?
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What ensures that the inducer fan is in proper operation before the furnace is able to
continue its heating process?
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What does the module do when it completes the safe- start check?
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Once the pilot flame is present, what does the module do next?
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Describe post purge cycle.
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When the furnace has completed the heating cycle, what happens next?
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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:
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What are some ways to reset the lockout for trial for ignition?
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List the two different types of wiring diagrams that are usually available in HVAC equipment.
pictorial (connection), schematic (ladder)
Are there any standards set for the electrical symbols and abbreviations in wiring diagrams?
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Which type of wiring diagram uses wire colors in its schematic?
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connection diagram
Do the wiring diagrams show with power or no power?
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What is the benefit of using a ladder diagram over the connection diagram?
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it is most helpful in determining the sequences of operation of the appliance for the purposes of troubleshooting.
When working with a thermostat, there are the following terminals: R,W,Y,G,C,W1,W2.
Identify what each letter is used for.
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What does IDM stand for?
induced draft motor
What does PRS stand for?
pressure switch
What voltage is at the “R” terminal when energized?
24 vac
About how long does it take for the hot surface igniter to warm up?
17-34 seconds
What is the “Spare” terminal used for?
________________
What is the average time allowed for the Post Purge?
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30 seconds
When replacing a fuse in the furnace, it is best to replace it with:
the right size
Replacing electrical components in the furnace must be installed as per the manufacturer’s
specifications. (True/False)
true
What are the fan speeds adjusted to when starting up the furnace?
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What does DIP stand for?
Dual in-line packaged
What two methods are normally used to change the fan off delay in the furnace?
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.
Do all ignition control modules (gas fired furnaces) come with Light –emitting diodes?
yes
What is good about the LED codes in a furnace?
good for troubleshooting, diagnose normal condition or a faulty one,
