[johnmay]

The front-center burner on our cooktop won't light. When we turn on the gas, the ignitor sparks maybe once and then stops, while the ignitors on the other
five burners continue to spark. Since this was the most commonly used burner I suspect it got gunked up somehow. I've cleaned all the external parts I can see and gently scraped the exposed metal parts of the ignitor with an emery board. Sometimes this helps for a while (or maybe it's just coincidence) but it seems to be getting harder and harder to make this burner light with its own spark. It lights fine with a match, so there is no problem with the gas.

[Gene]

The first failure suspect is the burner igniter.

- The part number for the igniter is AP2838563

If it would not help then replace the spark module (#30 on the break down diagram).

- The part number for the spark module is AP2836547

Here are the break down diagrams for the Thermador cooktop Model PCS366

Gene.
P.S. I would recommend to buy a special burner ring tool which will help you to remove a burner ventures.

[johnmay]

Thanks for the pointers. Using the breakdown diagram, I was able to figure out how to disassemble the burner so I could remove the ignitor. (I didn't realize until I looked more closely that the brass rings on the venturi could be unscrewed). Gene must already know this, but for other readers, if you unscrew these rings, you can remove the whole two-burner section, or the individual burner bases if they are not stuck down with burned grease. Once the section is out, it's easy to take everything apart and clean it thoroughly. I just carefully cleaned the ignitors and removed as much gunk as I could from everywhere, to ensure that all the right electrical contacts were being made. Once I reassembled everything, the problem was fixed. Of course, you could order a new ignitor, since they are cheap, but 15 minutes with some degreaser and a scouring pad worked for me.

[Gene]

You did very good job! Most complicated problems end up being simpler than they seemed.

Gene.

[ckit]

It is clear that it is important to keep the connection between the ignitor, burner base and stove top electrically sound. Reading this thread, I used a 13/16 socket to unscrew the brass venturi and remove the burner plate (with ignitor attached). I washed this with Simple Green the used a fine grit sandpaper to clean under the ignitor base and burner base. The burner works just fine now! Thank you for the clues.

[woodyw]

I have similar problems and not sure what to use to remove the ring. The ring tool suggested by Gene is out of order on the site. Can't imagin socket will do the trick, there is not room to stuck the socket in. Any other suggestion? thanks

[Gene]

Originally Posted by woodyw

I have similar problems and not sure what to use to remove the ring. The ring tool suggested by Gene is out of order on the site. Can't imagin socket will do the trick, there is not room to stuck the socket in. Any other suggestion? thanks

Have you speak with the APP customer service regarding the ETA on this tool?

Gene.

[woodyw]

Originally Posted by Gene

Have you speak with the APP customer service regarding the ETA on this tool?

Gene.

Yes. Just talked to them. It is a special ordered tool. It takes 2-4 weeks to ship.

[Gene]

Originally Posted by woodyw

Yes. Just talked to them. It is a special ordered tool. It takes 2-4 weeks to ship.

Unfortunately I do not see any other solution.

Gene.

[woodyw]

Just received the tool and unfortunately it doesn't fit

One end is too wide to fit in the hole and the other end is too small. I double checked and the model number is correct.