[Matt Schauer]

Have a cook top that sparks ocassionally when cook top is not in use. Sparks more frequently when in use. Gas only comes out when knob turned and operates normally (except for additional sparking while in use). It has simmer feature which will shut flame down and restart every 10-20 seconds on 2 of 5 burners. 2 Parts debating on replacing... Spark Module Kit (igniter) AP2836547 and Control Unit (gas simmer controller, I think) AP3672574. Igniter is working correctly and when knob is turned ignites as usual. Note all igniters (5) spark when any 1 knob is turned, not sure if that is correct or not. Wasn't sure if simmer controller was defective and sending signal to ignite even when in off position. Any thoughts... any type of flame sensor that could be sending bad signal for restart..even when in off position?

[Admin / APP Team]

I'll let Gene answer this one. He's the Thermador Master!

[Gene]

Matt Schauer
The problem with your cook top is what we call “technician's nightmare” because it is almost not possible to diagnose instrumentally.

The following are the common causes of continuous sparking and tests I would recommend you to perform:

1. Defective spark wires.
Continuous high heat can cause spark wires to degrade. Use volt/ohm meter to determine continuity 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 fire 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 flame would provide under normal circumstances. This will cause the spark module to re-ignite

2. Cracked Ceramic Spark Electrode
It’s important to determine whether the spark electrode is faulty. Physical impacts and high heat can cause the ceramic post to fracture or crack. If this occurs the spark can shoot through the ceramic insulation and will normally go to ground on the burner head rather than through the flame/burner spreader ring.

3. Faulty Burner Grounding
From the spark electrode / burner spreader ring to earth ground it is important that you have a strong connection. This can be interrupted in many different ways.

a) Soiled spark electrode
b) Soiled burner spreader ring
c) Soiled burner head
d) Corrosion between the burner head and burner tube.

Any of these conditions can interrupt current flow. We recommend frequent cleaning with a stiff plastic or soft wire bristle brush using pure alcohol or a window cleaning solution that contains alcohol. It is commonly thought that simple igniter cleaning is enough, it is not. You have to clean all three conductive components to ensure good continuity. A small amount of grease or oil can act as an insulator and prevent the spark from flowing properly. The burner head and burner tube connection has to be tight.

The fastening nut that holds them together has to be seated properly in order for the two
components to properly pass electrical current.

4. Poor house ground
If you have thoroughly diagnosed the spark system and continue to have erratic sparking do not dismiss the home ground as the culprit. Many older homes that are being remodeled do not have adequate ground systems in place to handle today’s demands. A quick diagnostic tool is a 20-foot piece of 16-gauge wire with alligator clips on each end. This can be used as a temporary jumper to a known ground source (water pipe). If the problem is eliminated when you connect the jumper you have to suspect the home ground as the culprit. When tested, the Neutral and ground should share less than 20 volts. It is common to find one or a series of burners that will only spark occasionally. As with the previously described scenarios check all possible ground faults. This is the number one cause of erratic sparking, not spark modules as is more commonly thought. If you have made certain that you have a strong flame current / flame placement / solid ground; replace spark module.

For your reference, here you can find the break down diagrams for the Thermador cook top Model SGCS365RS

Good luck.
Gene.

[Matt Schauer]

You "sparked" an idea/thought. 2 things: 1) I noticed 4 of the 5 burners did not have the red O ring gasket. The remaining one was brittle and crumbling. I assume these are used to isolate the ground and draw the spark to the flame burner spreader? 2) I did notice spark from some igniters occasionally would ignite straight down to cooktop surface (at base where ceramic on igniter met SS cook top) and not over to the flame burner spreader. The proximity was close enough to ignite gas. My plan is to order up some new gaskets and clean/inspect the igniters (replace any if cracked) and check for good house ground. I think this might resolve the issue. Appreciate the help. Will confirm when parts are recieved and installed.

[WhyThermador]

Hello, would the turning the knob activate the sparks on the xlo knobs connected to the simmer control module if the gas was not connected?
I'm wondering and hoping that this is the case because we have a professional cooktop that has 4 burners, the two burners on the right give sparks when turned on, but the two extra low knobs that are connected to the simmer control module seem to do nothing when the knob is turned. Even the red light doesn't go on. Is gas the issue or do I have something broken im my cooktop?
Thank you very much
Stacy

[Matt Schauer]

I gave it a try. All 5 burners were sparking with gas line (off) and removed. Still having problems. None of the igniters bad (visual and igniter test) and gaskets replaced. OHMed out the lines and see no problem there. All very good condition and no indication of over heating, pinched lines or other comprimised wires. Neutral to ground testing ok (less than 1 volt). Hooked up extra ground line from unit to galvanized water line for better ground.. still seems to spark occasionally. Ordering Spark module. I assume this hopefully should take care of issue. Will post when part is received and installed. Service on ordering gaskets was good and timely. Highly recommend. Hopefully I will have resolution soon.

Note to previous post: Ingiters on both XLO are operating as they should. Have correct delay and ignite normally. The only problem is the additional sparking.. happens 1-3 times per hour. No set pattern.

[Gene]

Hi Stacy

The two burners with the xlo future have absolutely different ignition system compare to two other burners. Instead of regular ignition switches they have a potentiometers.
Most likely the problem is a bad potentiometers.
To find out exact parts for your range I need the complete model number.

Gene.

[Matt Schauer]

Here is the results: Ordered the spark igniter.. no such luck. Frustrated..looked further. Zoned in on simmer control. Had back cover that could be easily popped off. Saw 2 brown darkened spots on terminal board. Figured that was the source of the problem. Ordered the simmer control... peace at last. FIXED!!! looks like I have a spare igniter on my shelf if it ever goes out in the future. The info here was good and timely. Orders were taken and processed well. Appreciate the forum. Thanks again and hope I never need the service again, but highly recommend to anyone a little handy and looking to fix it themselves. Thanks again.

[DutchBoy]

Originally Posted by WhyThermador

Hello, would the turning the knob activate the sparks on the xlo knobs connected to the simmer control module if the gas was not connected?
I'm wondering and hoping that this is the case because we have a professional cooktop that has 4 burners, the two burners on the right give sparks when turned on, but the two extra low knobs that are connected to the simmer control module seem to do nothing when the knob is turned. Even the red light doesn't go on. Is gas the issue or do I have something broken im my cooktop?
Thank you very much
Stacy

WhyThermador,

Sorry I can't help you, but I have the exect same problem on my PG-30. It's brand new and I connected it yesterday. The normal burners on the right work, as does the oven. The 2 XLO burners don't spark and gas doesn't flow. The blue light of the XLO burners does come on when I turn the knobs.

Called Thermador and they suspect the ignition switch and have given me the numbers of a couple repair folks. They don't have time to come out until next week... but they did tell me it was safe to use the two working burners and oven. Does anyone disagree with that?

Thanks,

JB

[drchasbe]

I have a 4 burner Thermador dual fuel oven/cooktop, RDSS30. During an oven cleaning cycle, one of the xlo igniters began to spark. When I tried to turn the burner on, the flame came up for a moment and then the gas to that burner shut off. I tried both burners several times with the same result. I left it alone and let the oven finish the cycle. The next morn, the xlo burners were entirely dead. No spark, no light, no gas. The two burners on the opposite side are fine. Igniter? Gas control? One of the Pots? Thanks, cb