Heating cells?

So everything I'm seeing says that you toss in 10 heating cells, they'll heat the reactor up to 10k heat.

So why when I use: http://www.talonfiremage.pwp.b…e37a65csq4je1hnc0st7ogq2o

To try to make a breeder, and toss in the 18 cells it shows in the design, the reactor happily sits at 24 heat... Am I doing something wrong?

No I think you misunderstand. With the reactor off, everything in-place but no redstone current, and 18 heating cells, the reactor hull temp sits at around 25. Not 25k, not 18k, just 25.

I had to toss in double the normal cells so it would heat up with the reactor off, then pull out half and turn the reactor on, at that point, with the reactor ON, and 18 heat cells, it kept it at 18k heat.

Either my understanding of how heat cells are supposed to work (1000 heat per heat cell in a stack, stops producing heat when the reactor hull reaches 1000 x stack size), or heat cells aren't working properly.

Ah hah!
Okay, I get it now, thanks for the updated design and the clarification on how to properly use heat cells.

Oh my god though, that's so much copper. It's taking me forever to find copper. I'm overflowing in Tin, even Iron, but so short on copper.

Quote from baturinsky

If you want it to keep temperature without uranium cells inserted, this
http://www.talonfiremage.pwp.b…i07qky0nyjcumcv33p5grssu8
can be a cheaper solution

Thanks for this design. It's perfect and cheaper than making 57 heat cells.