Why Do It?

The screen should not need changing in normal usage but, although it is metal, it is quite delicate and can be pierced (if for example you drop a screwdriver on it) or as happened in my case, it was damaged by the courier who delivered it. (I am told that packaging will be changed in future, so this should not happen again – but as with all things pond related, if it can happen, it will)
Tools Required

Crosshead screwdriver or cordless
Allen Key (2mm)
Stanley Knife
Time Required
20 minutes
Equipment Required
New/Replacement 50 micron screen
Process - Removal

Lay the drum on its flat side (there is only one)
Remove the 2 bands on each side of the drum, they are held by allen bolts and hold the sides of the screen in place
Across the drum, there are 2 ‘end clamp’ bars holding the ends of the screen and 1 bar in the middle providing tension
Rotate the drum until the single 'tension' bar is accessible in the open area under the drum housing
Remove the single ‘tension’ bar (it is held by 3 screws)
Rotate the drum until the 2 ‘end clamp’ bars are accessible in the open area under the drum
Remove the 2 bars holding the ends of the screen (3 screws each)
The screen is now free to drop off. Remove from the drum.
Process – Replacement

Drape the new screen around the drum (open the lid so you can ensure it is under the washer jets and in the correct position)
Loosely fix one end of the screen in place by inserting the central screw through one of the ‘end clamp’ bars and fitting it back in its original position (Note the 2 end clamps each have a top (where the screw is inserted), a flat side and an angled side. The flat sides butt together such that the angled sides are in contact with the screen and pull it down tight to the drum.)
Pull the screen tight and fit the 2nd ‘end clamp’ bar loosely with one screw
The excess screen can now be removed. Although it is metal, it is reasonably delicate and can be scored with the Stanley knife where it protrudes between the end clamps and then the excess torn off
If the edge is at all ragged, push any protruding edge between the end clamps
Now tighten the end clamps and fit the remaining screws
After checking the screen is properly fitted and reasonably taught, refit the ‘tension’ bar and confirm that everything is as it should be
Now refit the 2 edge bands
Make one final check that everything is as it should be and then put your drum back into your filter system