Here's another one with some differently worded instructions (note that I didn't say "different"--but the explanation is a bit different).
http://www.freeinfosociety.com/site.php?postnum=768
And another:
http://www.seascouts.ca/resource/pipe1.htm
That said, as far as I know, it should blow the low note just like a whistle, as long as you aren't covering the hole with your hand. If it doesn't, there may be something wrong with it.
I did find some sites that discussed tuning it, which involves reworking it by soldering/flattening/filing. However, that is to perfect the sound--it should make one on it's own, however nasty.
:::shivering in remembrance:::