De-Limer gas water boiler

Has anyone heard of this unit? It came with the house we bought and I was looking for a drain pipe, but for the life of me, couldn't find any. Shouldn't they be at the bottom of the boiler? The only thing that remotely looks like one is about 2 or 3 feet up from the base. It has a weird looking knob. But i thought that to drain water boilers, the sediment usually sets at the bottom. I can take a picture..but i don't know if this forum allows pictures.
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