Filter Replacement
Prefilters should be replaced at least annually,
or more regularly dependent on environmental
conditions. To be certain if the active carbon
filters require changing, we recommend using
the NO2 testing kit or the Carbon Life Prediction
Service.
Prefilter
Prefilter can be changed by the householder.
Replacing the prefilter for a higher grade (G4 to
F7) will increase the system resistance and may
require re-commissioning to maintain the design
airflow rates.
Active Carbon Filters
Changing of active carbon filters should be
carried out by experienced or trained personnel
in accordance with safety requirements as
defined by the “Control of Substances Hazardous
to Health” (COSHH) Regulations. i.e. Someone
who fully understands the design, operation and
implications of the product and its use.
NO2 Testing Kit
A NO2 testing kit is available from EnviroVent
that can be used to determine the levels of NO2
within the property. The testing kit requires a
minimum of 8 hours of exposure to the air and
during this time the property must be sealed
from the outside air meaning all doors/window/
vents closed and only the ventilation system
containing the NO2 filter to be in use.
This will give an accurate result for the
performance of the NO2 filter. If the levels of NO2
are greater than 40µg/m3then the filter should
replaced.
The 8hr exposure test kit consists of a plastic
container with a removable black plastic cap.
If the testing kit is not to be used immediately
after receipt then it must be stored in a sealed
polyethylene bag or similar and kept in a
refrigerator.
Instructions for use
1. Apply sample identifier that comes with the
kit to the back of the sampler.
2. Fix the sampler to a vertical surface using
adhesive tape, blu-tack or similar.
3. Remove the black cap and store in a safe
place. There is a minimum of 8 hours of
exposure and can be exposed up to 72 hours.
At the end of the exposure period, replace
cap and label the sample with the barcode
label provided.
4. Affix the corresponding number label to the
exposure sheet.
The testing kit should be returned within 2
weeks and must be stored in a refrigerator
until dispatch.
Carbon Life Prediction Service
If requested, EnviroVent can provide a Carbon Life
Prediction Service. Part used filters can be sent to
EnviroVent whereby they are tested to determine
the life expectancy of the carbon cells in use.
If the filters are likely to have been exposed to
hazardous contaminants then EnviroVent must
be informed of this. Please contact EnviroVent
for more information.
Maintenance
