Dacor CABP3, Technical Manual

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Technical Manual - Page 14
The fl ame also plays a very important role in this process. Because the fl ame is conductive, it
allows the voltage to pass through its body like a bridge to the burner spreader ring. This {bridge}
allows the built up spark voltage to bleed off of the igniter tip and move to ground more easily. The
resultant ionized fl ame bridge has now become the path of least resistance for the spark to take
across the gap between the spark electrode and the burner body.
By bleeding off the buildup of voltage we stop the spark from occurring. The spark is, in effect,
still there, you just canʼt see it.
* Ionized / To separate into Ions or to become electrically charged.
In order to successfully detect a fl ame we fi rst need to;
1. Place the electrode in the correct position under all fl ame conditions.
2. Ensure the fl ame is stable and does not “lift off” the burner at the ports adjacent to the
electrode and put the fl ame beyond the electrode. It is very important to have a stable fl ame
especially around the igniter tip.
3. Ensure there is a secure ground path to earth from the burner spreader ring / burner head.
4. Confi rm the appliance is properly connected to earth ground.
Current Path
The current path for detection is through the spark electrode, outer plume of fl ame, burner spreader
ring, burner head, burner base, chassis and earth ground. If this path is broken, the current cannot
fl ow and sparking will occur. A proper fl ame will keep this from happening. In other words, the
current will always fl ow through the path of least resistance and it might not be on top of the
cooktop, it might be below the top frame and out of sight. In this case, suspect a defective spark
wire or a pinched spark wire.
Do you have a ground prior to the igniter tip?
If there is a current path (leak / ground) prior to spark electrode,there will likely not be a spark
pulse between the electrode and the burner spreader ring. This phenomenon is what leads most
servicers to believe they have a defective spark module.
The spark module can tolerate a relatively large leakage before going into fault condition and
generating a spark. The tolerance to leakage decreases with an increasing amount of fl ame current
therefore it is desirable to obtain a high fl ame current at the appliance design stage to provide
some allowance for increasing leakage with age and use. The better the fl ame current / ground,
the less likely there is to be reignition.
Possible Causes Of Continuous Sparking:
Defective spark wires.
Continuous high heat can cause spark wires to degrade. Use volt/ohm meter to determine continu-
ity of spark wires. Look for obvious cuts/ abrasions or pinch points. A defective wire can allow
spark voltage to transfer through insulation to ground prior to reaching spark electrode. Under
normal circumstances all igniters fi re together and if the burner in question has found an easier
ground path the spark will go there. It will not, however, in most cases have found a CONTINUOUS
ground path such as what the fl ame would provide under normal circumstances. This will cause
the spark module to re-ignite.