My current set-up is the one attached below (not mine), with 15 Heat Exchangers and 15 Stirling Engines, outputting somewhere around 600-680 EU/t and 260.000 hU/t. It is attached via Glass Fibre wires directly to my energy storage and my Molecular Transformer. Apart from one almost-meltdown, this set-up has been almost completely stable and self-healing, with it getting as much cool coolant in as hot coolant out through the Heat Exchangers and Stirling Engine combo.
However, when I redirected my wires back directly to my energy storage, I quickly found that all my coolant had turned hot and my reactor almost had a meltdown. As well as this most recent encounter and the previous one, I do not know what happened and what flaws are in the reactor.
Diagnosis, anyone? Also, any effective way of turning all the hot coolant back to cool coolant and back into the reactor? The Heat Exchangers are full to the brim with hot coolant.
You need to have the appropriate number of exchangers for the HU output of your reactor.
I think one Heat Exchanger can handle 100HU/t when fully loaded with coils.