Wiesenfield WIE-FS-220HAT Manuel D'utilisation page 75

2 – Belt tension bolt
Rotor blade Replacement
Frequently check rotor blades to make sure they are in good working condition
and properly secured to the rotor. Replace worn or damaged parts with new
blades.
IMPORTANT:
Make sure that the replacement of blade with other same weight. This will be a
balance of rotor spinning.
IMPORTANT:
The replaced blade must be the original factory accessories.
The blade have a Crushing edge on both the leading and trailing edges. When the
leading edge wears out, turn existing pair of blade around 180 degrees and
reinstall. Replaced blade should be the same length as existing part to maintain
rotor balance.