I bought a couple Hela fans for my fine yacht about a month ago. The two
wires were labeled (+) and (-) and I connected the (+) wire to the positive
wire (red) from my distribution pane. Lo and behold, the air blew out the
BACK of the fan. Duh! The Hela fan has asymmetrical blades with a bit of a
scoop to the trailing edge to better force the air forward. When running
backwards not only does the fan not blow as much air but the shielding and
off/on knob ends on the back of the fan where it is hard to access.

So, I connected the (+) wire to the black (negative) wire from my
distribution panel and it now blows the air out the front of the fan. It
blow the air more vigorously to boot as the fan blades are operating in the
right direction.

So, here's a clue to those of you who have a Hela fans. The air should be
blowing out the front where the off/on knob is located. It it is blowing out
the back (which is open and has no shrouds) then you have it wired
backwards. But, since the wires are labeled wrong from the factory you are
forgiven your blunder.

Wilbur Hubbard