This information is from David McGibbon, Festool Tech Support. I couldn't find it on FOG or the Festool USA website, so:
In general (all vacs, any country): Remove the paper filter bag before vacuuming liquids (duh!) The final filters should be replaced with the sponge variety (452924 for CT 22, 33, and so on; 456805 for Mini and Midi). These sponge filters are not expensive. The CT bottoms are watertight, and you can remove the top for emptying. If you do this often, you might want the removable bucket accessory (452925 for CT22, 452926 for CT33). In addition to being more convenient, it also keeps foaming down in the waste area.
Don't ever get HEPA filters wet. If they get wet, the creases in the filter material will flatten out and the airflow will be severely and permanently restricted. I think HEPA filters are only supplied in North America.
The standard-grade filters are a little better than HEPA for moisture, but it's still not a good idea to use them for wet work.
The optional Longlife filters (454869 for CT 22 and 33) will tolerate some moisture. They are made with high-strength three-ply polyester fleece, and are particularly robust and washable.
Never leave anything wet or damp in the machine. Remove the wet filters, dry out the cavity and/or bucket. If you don't, the interior of the vacuum will be an ideal breeding ground for mold and mildew.
To clean the filters, simply tap them to make the heavier particles fall off. If you insist on drying the filters with compressed air, keep the pressure extremely low--5 psi (0.35 bar).
Ned
In general (all vacs, any country): Remove the paper filter bag before vacuuming liquids (duh!) The final filters should be replaced with the sponge variety (452924 for CT 22, 33, and so on; 456805 for Mini and Midi). These sponge filters are not expensive. The CT bottoms are watertight, and you can remove the top for emptying. If you do this often, you might want the removable bucket accessory (452925 for CT22, 452926 for CT33). In addition to being more convenient, it also keeps foaming down in the waste area.
Don't ever get HEPA filters wet. If they get wet, the creases in the filter material will flatten out and the airflow will be severely and permanently restricted. I think HEPA filters are only supplied in North America.
The standard-grade filters are a little better than HEPA for moisture, but it's still not a good idea to use them for wet work.
The optional Longlife filters (454869 for CT 22 and 33) will tolerate some moisture. They are made with high-strength three-ply polyester fleece, and are particularly robust and washable.
Never leave anything wet or damp in the machine. Remove the wet filters, dry out the cavity and/or bucket. If you don't, the interior of the vacuum will be an ideal breeding ground for mold and mildew.
To clean the filters, simply tap them to make the heavier particles fall off. If you insist on drying the filters with compressed air, keep the pressure extremely low--5 psi (0.35 bar).
Ned