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Operation and Maintenance
Envistar Top 04-21
DSET.190501.01.EN
Continuous product development may give rise to specification changes without notice.
6.2 Filters (code ELEF)
The air filters in an air handling unit are designed to prevent dust
and other impurities from entering the building. They should also
protect sensitive components inside the unit, e.g. water coils and
heat exchangers, from exposure to impurities.
The dust separation efficiency varies considerably between
various filter types. The dust collecting efficiency also varies
substantially.
It is therefore important to use filters of the same quality and
capacity when you change them.
According to guidelines for hygienic design VDI 6022 Part 1: The
supply air filter must be class ePM1-50% (F7) or have a greater
filtration efficiency.
The filters are designed for one-time use. If they become
fouled, the unit will lose capacity. The filters should therefore be
changed if the pressure drop across them exceeds the specified
final pressure drop.
It is important to stop the unit before changing filters to prevent
dust from coming loose and being drawn into the unit. The inside surfaces of the
filter sections should therefore also be cleaned when the filters are changed.
Lifespan and filter control Carbon filter
The function and lifespan of the carbon filters depends on the volume of air
that passes through and on the molecular density of odorous substances. This
means that the time intervals for filter replacement can vary from unit to unit
depending on operation mode and the volume of odorous substances in the air.
Units delivered with control equipment (code MX) are equipped with the filter
control function – FLC (Filter Lifetime Control). FLC indicates when it is time to
replace the carbon filter. Indication is through an alarm on the Climatix display.
FLC calculates the volume of air passing through the carbon filters and triggers
the alarm for filter replacement when the preset value has been reached. The
volume of air passing through is measured in mega cubic metres (Mm³). The
function does not take into account the odour content of the air, which means
that the indication should be regarded as a recommendation for checking the
filter function. If no odours pass through, there is no need to replace the filter.
Preset FLC values are based on max. air flow over 12 months of full-time opera-
tion. If required, the value can be lowered in order to: - change to more frequent
Filter
