After some failed attempts I came up with the method outlined below, which has been running flawlessly ever since. No combinators or complex timers are used (yes, figuring out how to set these up is fun. But I wanted something simple and reliable in place fast, ‘cause I was wasting fuel cells by continuously inserting them into my reactors).
The setup:
Have a belt load fuel cells in chests next to the Reactors (limited to a single slot, no need to fill the entire chest). Wire one of your (connected) Steam Tanks to the inserters feeding your reactors and the inserters between chests in the control setup, as in this schematic:
How it works:
There is a single Fish in chest 1. When the steam level in the tank drops below 2000, Inserter A is enabled, moving the Fish to chest 2. Inserter B generates a pulse when it moves the fish to chest 3. This pulse is the trigger for the inserters feeding your reactors to load 1 fuel cell. Once the steam level is high enough, inserter C moves the fish to chest 4. This prevents small fluctuations of the steam to trigger multiple refuels. Inserter D moves the fish to the first chest, where it will stay till the next refuel is at hand.
in-game:
I made the sytem described above, and it hasn't malfunctioned in the 50 hours I've spend on the map since. Everything is tested 'in the wild', I don't use creative mode
My factory is quite small (haven’t even launched a rocket yet in this game), but the large island/continent it is on has been cleansed of Biters, so I’m not in a rush. I’ve invested resources in building 8 reactors (which count as 28 'effective' reactors with the bonuses), 28*4=112 Heat Exchangers and
This would support 28*7=196 Turbines, but I need just 9 now. I've attached a speaker to the Fish pulse, so every two hours I get a *ding* that indicates my reactors have been fuelled up.
Notes:
-when placing the first Reactors, or adding new Reactors or Heat Exchangers, manually load fuel for the initial heating.
-make sure you have enough tanks to capture all the steam.
-the image above shows the control setup, not an actual layout for Heat Exchangers etc. In my game I stack rows like the image below for every 4 ‘effective’ Reactors (so when you extend your 2x8 setup with 2 extra Reactors to make it 2x10, you'd add two of these rows, as you're adding 8 'effective' Reactors). Every row is fed by two pumps, and has 16 Heat Exchangers,
- first time poster, hope I didn't re-invent a wheel, but couldn't find a setup like this here. Simplest is probably vanatteveldt's "Very simple controlled reactor setup" (to which I can't link 'cause URL's are not allowed in a first post, it appears :-/) . Wish that had been available when I was searching Hope it is of some use!
*edit: typooos :-/
*edit: doubled amount of tanks