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22 Cards in this Set
- Front
- Back
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What is the main difference between an intermittent pilot gas valve and a direct ignition gas valve? |
The direct ignition gas valve has no pilot connection. |
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When using electronic ignition what is the process of flame proofing called and what is the instrument called that accomplishes it? |
Flame rectification, a flame sensor is used (micro amps DC) |
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What is the minimum flame rod to ground electrode area that is immersed in the flame? |
1:4. The grounding electrode has to be at least 4 times larger then the flame proofing rod. |
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Why have flame conductivity systems not been used in the past for proofing flame? |
The system will not distinguish the difference between a flame and a short to ground. |
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What is the average temp. of a HSI? |
2600 F |
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In short what is the sequence of operation for a 90% gas burning furnace? |
Thermostat calls for heat, draft inducer motor starts, closes pressure switch, sends power to HSI, once HSI reaches temp gas valve opens, flame sensor rectifies flame, blower starts after the delay is met. Call satisfies and thermostat ends call. |
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What is the importance of the connection diagram? |
It shows where the wires connect to and the colors of the wires. |
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Why is the ladder diagram important? |
It shows how the appliance works for troubleshooting. |
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What are the four ways that electronic ignition systems can be configured? |
- Intermittent pilot using spark - Intermittent pilot using HSI - Direct ignition using spark - Direct ignition using HSI |
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T or F
Interrupted pilot ignition systems remain on during a call for heat. |
F
Interrupted pilot systems turn on when a call for heat prevails then turns off once the flame is rectified. (HSI) |
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What is one example of a intermittent pilot ignition system? |
A Direct Spark Ignition system is one example of a intermittent pilot. |
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What is the difference between a intermittent pilot system and a interrupted pilot system? |
In an interrupted pilot system the pilot only stays on until the flame is rectified. Once flame rectification takes place the pilot is extinguished.
In an intermittent pilot system the pilot remains on throughout the whole call for heat.
Both pilot systems remain off with no call for heat. |
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What is the is the recommended "spark gap" on a Intermittent Pilot Spark Ignition System? |
The recommended "spark gap" is 1/8" |
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What is the difference between a Dual-Road burner and a Single-Rod burner ignition system? |
The dual rod has two rods. The first rod (the shorter of the two) is the spark igniter. The second rod is the flame sensor.
The single rod uses the same rod for flame sensing flame and creating a spark. |
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What is the potential voltage of the spark ignition rod of a dual rod system? |
13 kV (13,000VAC) |
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How does a 24-Volt Hot-Surface Intermittent Pilot ignition system work? |
It works by using a Silicon Carbide igniter itself as a flame proofing device. The downside is that over time oxides were produced and they would impede the current flow causing the the product to fail needing replacement |
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How does a Direct Spark Ignition System work? |
It works by using spark ignition to light the main burner directly causing it to be an interrupted pilot system. It uses a sparking rod with a grounding surface to create the spark arc. A flame sensor is then connected to the ground terminal on the module for flame rectification. |
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What do you have to cautious about when working on a HSI system with a Silicon Carbide igniter? |
You have to be cautious not to touch the Carbide portion, the igniter should only be handled by the ceramic base. it may also be hot. |
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T or F
A hot surface igniter can be used to sense flame? |
T
On an HSI system the HSI can be used to sense the flame or a separate flame may also be used. |
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What are some things to be cautious about when cleaning a Flame Sensor? |
You can not use an abrasive cleaning item (Sand Cloth) to clean it. As it will leave deep scratches and it will mess up the ground to flame ratio and the system will fail to prove flame. |
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What are the two main principles when it comes to sensing flame? |
Flame conductivity, and flame rectification. |
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Why are flame rectification system better then flame conductivity systems? |
Flame rectification systems can distinguish the difference between a short circuit and flame. |
