How to Troubleshoot & Replace Bosch AP3782975 / 00422748 Potentiometer

APP was able to find, even in light of no model number available, a replacement part which was regrettably no longer available from the manufacturer, nor from a 3rd party supplier. APP provided me with a schematic to help in this solution, and were very diligent in making sure that I could order a part which may or may not work given the issue. To my relief, the part has worked well. I find the APP team to be most friendly and helpful far beyond what I might normally expect. Appreciate this very useful service indeed. 

The biggest problem is taking apart the cooktop venturi/burner assembly. They were fused after 20 years of use. These have to come out to get to the electric gas solenoid which I thought was not opening to let gas to the burner. I ruined the two Ventura’s and jet holder and the two gas lines getting them out and replaced them with new from appliance parts pros. Before I destroyed the old parts I figured out that it wasn’t the solenoid that was bad but I wanted to be able to see how everything looked underneath in case I needed to get to them in the future. First I made sure that the parts I was going to destroy were in stock and they were so I used penetrating oil a 20 mm flat bottom socket and then a unit to drill the hex head off when the wrenches couldn’t loosen the venturi and started spinning the jet holder around breaking the attached gas tubing. I used 1/4” copper line from an ice maker to make new lines and put everything back together with anti-seize. The problem was the potentiometer. How I found out have I just switched the one that was working with the one that wasn’t and that was it. Appliance parts pros had all the parts in stock and shipped out to me in a few days and then it took me about a half-hour to put everything back to new condition. Works perfect for $105.00 thanks. 

The range is 22 years old. Quickly diagnosed that potentiometer was not sending a signal to simmer control unit to open gas solenoid valve. The original potentiometer was no longer available, but one of the stories on AppliancePartsPros.com said that this part, #00422748, was an equivalent replacement to the original. I took the chance and popped it in. It worked perfectly! The replacement was easy. 1. Turn off the breaker to the range. Remove the front control panel. Remove 2 screws one on each end of the panel, and on this model one in the middle behind the main oven knob. The panel pulled down with no effort after all fasteners were removed. 2. Pull the old potentiometer loose and remove the connecting cable. The pot pulled straight out. No need to remove the top or open any gas connections. 3. Connect the cable to the new pot and slide the new pot onto the valve shaft. 4. Replace the control panel and knobs. 5. Turn the breaker back on and give it a try. Took about 45 minutes total. 

The repair started with replacement of the simmer module as recommended. The key component to removing the cooktop is to remove the venture with the shallow 20mm nut. Which was locked beyond removal. At this point I used a machine shop 90 degree countersink tool to remove the nut portion of the venture. then I was able to remove the top. I then learned that I needed to order jet holders due to the venturis being locked into them. quite a project. bottom line, these potentiometers worked perfectly for the stove top. 

With the help of Appliance Parts Pros, I received the parts in a couple of days. The repair video was very helpful with the repair. The only delay was a wire came loose when I dropped the panel to replace the potentiometer. I called the tech and got a copy of wiring diagram and got it back together and it works fine. This is my 2nd experience with Appliance Parts Pros and both times I have been successful in repairing my 20 year old Thermador range. Would highly recommend your parts and tech department to all. 

The lady on the line was so kind and put me on hold while she checked with a technician. She recommended a part. It came in in a few days and worked. Thank you Appliance Parts Pros. 

Myself 

I changed the part ordered and now it is o.k. 

This range has 4 burners, 2 regular manual and 2 XLO which never worked properly since new installation and therefore I rarely used them. I asked a questions, described their behavior on this website and was told the potentiometer needed replacing. It did. After several years of cursing these burners they finally worked perfectly for the first time ever. I love my stove again, all 4 burners worth. Total fix took about 15 minutes plus another 10 minutes to clean out and dust. 

Replacing the potentiometer