External Heater

The External Heater is a machine added by Immersive Engineering, made to power a Furnace with Redstone Flux (RF).

To function, it should be placed next to a normal Furnace. Right-clicking one of it's sides with an Engineer's Hammer will allow that side to accept RF energy.

The Furnace will be able to smelt items without any fuel, from it taking energy from the External Heater. Initially, the External Heater will consume up to 32 RF/t, but once the Furnace reaches optimal temperates, it will only need around 8 RF/t to stay warm. However, it will still use 32 RF/t total: the other RF used will be used to speed the Furnace's smelting processes. If efficiency is preferred over speed, that functionality can be disabled through a Redstone signal to the External Heater, making it only consume around 8 RF/t.