Numatic Permatex Primary Fi...
$197.99
Product details
Part 604311 is the PermaTex primary filter listed for Numatic canister vacuums. Numatic describes its PermaTex filtration system as three high-efficiency layers built so that what goes into the drum stays in it, and a primary filter is the stage that holds dust back before it can be carried further into the machine.
- Part: 604311, PermaTex primary filter
- Fits: Numatic canister vacuums that take this primary filter
- Replace when: the filter is torn, saturated, or no longer shakes clean
A primary filter that has loaded up restricts airflow well before the collection bag or bin is actually full, so weak suction with a bag that still has room left is often this filter rather than the bag. Once the media is saturated with fine dust it stops shedding when tapped or shaken, and at that point cleaning it further does not bring suction back.
A filter is worth checking any time suction feels weak with a bag that still has capacity, since a filter can look intact from the outside while being loaded through and through. Holding it up to a light is a fair test, because dust packed into the weave rather than sitting on the surface shows as an even gray haze instead of letting light through cleanly.
Numatic's canister lineup uses more than one primary filter size, so match the number on your existing filter, 604311, before ordering rather than relying on the machine name alone.