How to Troubleshoot & Replace Bosch AP2821594 / 00188978 Nut

Bought a Thermador PRSE48" dual fuel range from Craigslist really cheap because it didn't work. Did a little research and decided to overhaul most of the top (gas) end. For what I paid for it it was worth it and I'd have a good stove with new components. Replaced the griddle thermostat, ignition micro switches, ignition re-igniter box, installed fixing kit with 2 new potentiometers, both solenoids, and gas regulator. Had to replace 2 gas lines, all 4 jets, and one brass nut that were corroded or damaged in removal. Replaced all igniters and clips and main oven door seal. Kept the wiring harness. The only issue was the directions for re-igniter are WRONG. Don't connect wires to the same "number" as directions say, instead connect them in the same "position" as the old one. I connected them to the number as directions say for 4-burner but the ignition won't stop after lighting - it just keeps ticking away. Pulled it apart and put them to the same position (it says to do for a 6-burner) and then it worked correctly. Spent about 2 months cleaning it - it was filthy inside and out. Now it looks great and everything works perfectly. A like-new 48" Thermador for the cost of parts. 90% of the time spent was cleaning. I'm just a DIYer and have never owned a stove like this or overhauled a stove before and it wasn't a bad project. 

Had two different repair companies come in to repair my Thermador PRG304US Range. Both explained the the "broken" parts were no longer available making the repair impossible and thus I would have to buy a new range. Ok, but before I shell out $5K to replace the one I had, I needed to answer the questions I had. After twenty minutes of online research and the help of AppliancePros I was able to repair my own range. The techs obviously mis-diagnosed the problem, and not only that the one guy "pretended" that he attempted a repair that he never did. Repair was not overly difficult for someone with a little "handyman" skill and common sense, but was time consuming. Had to remove multiple parts for proper exposure to allow replacement of solenoid. The Venturi Tubes were frozen also adding to the difficulty and time required. DIY repair videos that greatly helped me with the repair: https://www.youtube.com/watch?v=p5O7UV_aQjw https://www.youtube.com/watch?v=g8_rUV0wFyM 

Replaced both ignitors. Since I was working on the range I also overhauled the final 2 of the 6 burners on the stove top. Venturi tube and jet nuts were frozen and could not remove drip tray for cleaning and access to ignitor clip. Had to drill out Venturi tubes using a tapered bore bit. Used Dremmel with cutting wheel to remove jet nut. This range has been heavily used since new for 16 years. Works like new, again. 

The root cause of the problem was a bad potentiometer. The carbon tracks were worn out, and not providing electrical contact that energizes the gas control solenoid. In order to test the solenoid, I had to disassemble the cooktop, and the nut and "jet holder" were welded together from years of exposure to heat. Disassembling the old parts was difficult, but installing the new ones was easy. Note that the new potentiometer (AP3782975) appears to be a direct replacement for the old one (AP2825521). Thermador PRG304US 

I had to cut out the venturi with one of those vibrating tools with a narrow metal blade like a hack saw. Takes time and wear your ear plugs . I had two different repair guys here they both said I need a new range . It's 15 years old and 9 grand to replace it. No No . I'll fix it and I did . 

The oven was not heating, and there was no gas flow to the oven or spark. I replaced the spark igniter, but that did not fix it, so the problem was either the ignition device or the oven bake solenoid. In order to get to them, I had to cut the venturi tubes which hold down the burner rings with a Dremel tool, which was easy enough. There is no other way to get these tubes out if they are stiff or seized as you will simply twist the gas supply line to the burner if you try to rotate the nut. Also note you will need a very shallow 20mm socket to grip the nut if you try, which is not easy to find. I also had to cut off the old nuts holding the gas jets because they had also seized. Once I had access, I replaced the ignition device, and the oven worked, so the gas solenoid was not needed. I then replaced the gas jets, and venturi tubes, and the oven and range top burners are working again. Appliance Parts Pros was very helpful. 

Upon disassembly, I found the burner gas tubes were seized in the burner assembly requiring destructive disassembly to remove them. After drilling these out, I was sure that it would take weeks to source all of the parts and get them back together. In three days all parts were at my door and the range was back together that day. 

Ordered the parts from Appliancepartspros with the help of Kimberly. She researched the parts I needed from my description. All the parts we ordered were pictured on the email confirmation they sent. The order came sooner than promised and was correct and complete. From there it was just a matter of reassembling. Everything fit perfectly. Job finished in two hours. Nice to have six burners working again. By the way, another thank you to Kimberly