Also, Chocorate, you're using the wrong transformer. You need an LV-transformer if you want your electric furnace to not explode. Or a transformer upgrade.
Also, are those gold cables double-insulated? If not, you should probably insulate them again.
Also, you will want insulated copper cable coming out of the LV-transformer. Copper can't take as much EU/p as gold, but carries it more efficiently.
EDIT: Your MFE might not have filled when it was facing the right way because EU was getting stored in the transformer. The MV-transformer, if I remember correctly, stores 512 EU, and the geothermal only produces 20 EU/t, so the first few seconds worth of EU probably didn't stay in the MFE for very long.