Karcher vacuum bags
Karcher's WD range of wet and dry vacuums uses fleece filter bags rather than paper dust bags, and the correct reference depends on which WD size you own. Fitting a paper bag or the wrong fleece size to a WD vacuum will reduce suction and can let debris into the motor.
How to identify your Karcher model
Karcher wet and dry machines are identified by a WD number moulded into the body, and the number is the whole of the identification you need: the WD2 and WD3 sizes take one fleece bag, the larger WD4 upwards take another. Read the number on the machine rather than the one on the box it came in.
These machines use a non-woven fleece filter bag rather than a paper dust bag, because the bag has to cope with damp debris during dry-mode use. A household paper bag is not a substitute and will collapse.
Bags for Karcher machines
Each reference below has its own page on this site with the full list of machines it fits, the fitting steps and the mistakes that cost people a pack of bags.
| Bag reference | Fits | Capacity | Bags per box |
|---|---|---|---|
| Karcher WD2/WD3 fleece filter bag | Karcher WD2 and WD3 wet and dry vacuum ranges | Matched to the WD2/WD3 tank size (typically 12 to 17 litres tank, bag sized accordingly) | 5 bags (standard retail pack) |
| Karcher fleece filter bag, part number 2.863-006.0 | Karcher WD4, WD5, WD5 P and WD6 PS wet and dry vacuum ranges | Matched to the WD4 to WD6 tank size (typically 20 to 30 litres tank, bag sized accordingly) | 5 bags (standard retail pack) |
Where Karcher owners go wrong
- Fitting a WD2 or WD3 bag in a larger WD machine. The tank is a different size and the bag will not seat on the inlet.
- Using a paper household bag because the collar looks similar. Paper tears as soon as it meets damp debris.
- Running in wet mode with a fleece bag fitted. The bag is for dry work; wet pickup is done with the bag removed, following the machine's instructions.
When to change the bag
Fleece bags hold airflow longer than paper, so the usual sign is not a sudden drop in suction but a gradual one. On building or workshop debris, change the bag well before it looks full, because the fine mineral dust that these machines pick up blinds fleece from the inside just as it does paper.
Karcher bags: common questions
Can I use the machine without a bag?
For wet pickup, yes, following the manual. For dry work the bag is what keeps fine dust out of the filter and should stay fitted.
Are fleece bags reusable?
No. They are single use, and shaking one out releases the fine dust the bag was there to capture.
How do I tell a WD3 from a WD4?
The number is moulded into the body of the machine, usually on the front or the tank. Tank size differs visibly between the two families as well.