Finally found some time to replace the wiring of the oven. I yanked out the "controls" and redid the wiring. Installed two SSRs on heatsinks and three thermocouples. The result can be seen below.
I used some kapton tape to cover the bare 230V leads on the SSRs. I still need to fix their heatsinks to the bottom of the oven, for now gravity will do the job.
Please excuse the incorrect symbols...
I moved the thermal safety switch from the front to the back because the mains load wire isn't long enough... Mains L connects to the safety switch, so that power to the oven will be cut when the temperature gets too high. From there it goes to the SSRs. Each SSR is connected to one heater element (wires on the left of the photo, front of the oven). The other end of the heater elements are connected to mains null.
I also added three thermocouples in a more permanent setup. Each heater element has one thermocouple, the fiberglass sleeve of the thermocouple has been wrapped in some kapton, and I used a bit of iron wire to strap the kapton covered sleeve to the heater. The thermocouple's junction just presses to the heater. The floating thermocouple in the middle measures air temperature. It's held in place with, again, kapton tape.
I covered parts of the door with aluminium tape, hopefully that will reflect some of the heat.
The difference is noticable; the covered parts of the glass stay cool to the touch whereas the center gets warm. If this works well then I may just have to cover the entire inside of the oven with this stuff, but I'll have to check how well the glue on this tape holds up in the heat first. This is extremely sticky stuff by the way and very thin.
So with the cover back on I have a few wires poking out of the front panel: 3 thermocouple connectors and 2 times 2 wires for the SSRs. Looks like I didn't mess anything up. I didn't blow a fuse when I plugged it in, it didn't catch fire when I turned it on and it didn't kill me when I touched the metal cover. I'm almost disappointed :)
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