Quote: "otherwise it will explode"
Good source, bad quote. Did you read what behedwin is asking?
True: the hobbyist engine will (like any Railcraft boiler) explode when it runs out of water and then, while still hot, receives more water. However, with an aqueous accumulator present (in the same chunk), this should never happen.
The actual answer: If the engine fills up its internal buffer with energy it cannot output, it will stall, but not explode. You might be able to fix it by whacking it with a wrench or crowbar, but if that doesnt work, you'll need to break it and place it down again in that case.