If you're having issues with heat, try adding a "buffer". Use vents and outlets a stage higher than the exchanger between them. The exchanger is a few orders of magnitude smaller, so a percentage that doesn't show up on the larger ones shows up there. It gives you a warning about a heat issue before things start exploding. This can also work with other setups, the main part is having your 'buffer' object be one tier lower than the other devices.
Also, the upgrades are a -huge- benefit. Do not skimp on the upgrades. Upgrade your vents, upgrade your capacitor effect on your coolant system, whatever. Just upgrade.
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