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Standard Dry Filters
The NVD 750F (SNTD 750) is normally equipped with a 2 stage main filter assembly
immediately underneath the powerhead. This consists of a red Filtrex filter providing
5.0 micron filtration and a white Permatex 0.5 micron filter.
If higher filtration levels are required, it is possible to install a 2 stage Permatex (NVM
13B) / Microtex (NVM 10C) assembly instead of the standard filters. This increases the
filtration to 0.3 microns with an efficiency in excess of 99%.
As the standard become loaded with dirt & debris during use, they should be removed
periodically and brushed to remove the gross soil. Both stndard filters can be washed in
mild detergent & hung to dry. Do NOT wash the Microtex filter if this is installed in the
machine. The Microtex filter is easily identified by its bright yellow colour. It also has a
warning tag indicating that it should not be washed.
Optional HEPA Filter Module
As an optional accessory, the NVD 750F (SNTD 750) may be fitted with a HEPA filter
module. When this filter is used it must always be used with a Permatex filter as a pre-
filter. Failure to do so will drastically reduce the working life of the HEPA filter.
As a safety precaution in sensitive areas, it is possible to secure the HEPA filter module
to the powerhead by using split pins. These can be inserted through the holes in the
steel retaining toggles once they are closed.
The HEPA filter is capable of filtration to 99.97% to 0.3 microns even if the intake of the
machine is completely blocked.
The code for the replacement filter is NVM 25B. Replacement of the HEPA filter must
be carried out by qualified personnel.
Special Cyclonic Assembly
Below the main filter assembly is the special cyclonic assembly. The intake, to which
the vacuum hose is attached, is mounted so that debris enters in a tangential fashion to
enable "cyclonic" separation of dusts from the airstream.
To remove the cyclonic assembly it is necessary to first remove the transfer hose
screwed onto the rear of the assembly. Then lift up on the 2 steel toggles and release
the claws from the rim of the assembly.
Collection Filters
The standard filter supplied with the machine is a deep Permatex filter. In addition to
this the recovery tank is lined with an open paper bag (type-NVM 5B). It is also possible
to use the Permatex filter as a liner with the open paper bag as the main collection filter.
