Board Thread:Questions and Answers/@comment-66.253.245.118-20140110141850/@comment-13413401-20140111014621

If you are powering the Induction Furnace with a repeater, then this is why. Repeaters make it so that the block that they are facing is powered, but that block also becomes a restone power source, powering surrouding blocks. If you power the furnace with just redstone, red allow wire, or a torch, the problem should be fixed. If you used a button on lever, make sure to place it on a block next to the induction furnace, not on it.