Answer
Unplug the saw. Clamp the head's movement with the handwheels and remove the front blade guard. The lock nut is left-handed, so turn it clockwise with a 19 mm wrench to loosen it. Bring the head forward a little and tilt it so the blade lifts out. Look for debris between the flange and the blade, and do not use tools that could mark or bend the flange. Drop in the new blade with its arrow pointing the right way, then tighten the nut anticlockwise to 40 Nm (about 30 ft-lb). Pick a continuous-rim blade made for wet cutting that suits the material, and never use reduction rings to fit the blade hole.
Source
Reviewed by our parts specialists from IMER manuals and parts books. Check the part number on your machine or in its parts book before you order. Not sure? Ask a parts specialist.