Heat recovery unit RDKS - Technical manual
15
FläktGroup DC_9295GB_20190326_R5
We reserve the right to make changes without prior notice
DUCT CONNECTION
Exhaust air from the unit may only be connected to a ventilation
duct intended for this purpose. Connection must not be made to a
smoke or gas flue. In case of extract air ventilation in premises where
a smoke or gas flue is used (for instance, an open fireplace or heating
stove), an adequate supply air flow must be ensured A kitchen flue
must be installed in accordance with applicable regulations.
We recommend having a separate extract air device in the kitchen and
a boost damper with dense blades to ensure heat recovery from air in
kitchen.
DUCT CONNECTION, DUCT INSULATION
Note! During installation, the instructions regarding unit installation and duct insulation must be adhered
to without deviation. Otherwise, there is a risk of condensation and moisture resulting in major damage.
DUCT INSULATION
In order for the installation of the unit to be effective, it is crucial that
the installation of the ventilation ducts in the unit, as well as the instal-
lation of ducts through external walls containing insulation and vapour
barriers, roofs and joists, is executed in a professional manner. Other-
wise there is a risk of condensation, resulting in moisture damage.
If older units are replaced, it is also necessary to inspect ducts and
duct insulation for damage and ensure they are of adequate quality.
Supply air ducts (T) and extract air ducts (F), i.e. ducts containing
warm air, which are located in unheated spaces, must be insulated.
The insulation should be installed externally and have a wind-proof
surface.
Outdoor air ducts (U) and exhaust air ducts (A), i.e. ducts filled with
cold air, which are located inside the building’s vapour barrier, must be
insulated and have a diffusion-proof (moisture-proof) surface. Given the
high degree of heat recovery achieved by the unit, the exhaust air also
gets very cold and must be thermally insulated. Moreover, ducts which
run alongside each other must have a common vapour barrier.
For designations of the various ducts, see figure 15 on previous page.
The wall on which the unit is to be installed must be well insulated.
All figures in this table are recommended values which apply in central Sweden. Please check for local variations.
DUCTS IN WARM SPACES (INDOORS)
The temperature of the air
in the duct is above +10 °C
The temperature of the air
in the duct is below +10 °C
No insulation
Supply air ducts (T)
Extract air ducts (F)
Outdoor air duct (U)
Exhaust air duct (A)
Supply air duct (T)
Extract air duct (F)
Fire protection
mesh mat 30 mm
with moisture-proof surface
DUCTS IN COLD SPACES
Supply air duct (T)
Outdoor air duct (U)
Extract air duct (F)
Exhaust air duct (A)
DUCTS IN LOOSE WOOL
RECOMMENDED INSULATION AND VAPOUR BARRIERS FOR DIFFERENT TYPES OF DUCTING
Ducting type
Approved material and
location
Duct in a warm space
Insulation
Vapour
barrier
Duct in a cold space Insulation
Vapour barrier
Exhaust air (flue)
In kitchen
Sheet metal, accessible for
inspection
Armaflex AF3, 19 mm
Yes
–
–
Between joists and in attic
Sheet metal
Fire protection E15,
Yes
Fire protection E15,
Only inside
mesh mat 30 mm
mesh mat 50 mm
building's vapour barrier
Exhaust air (no flue)
Sheet metal
Mineral wool 25 mm
Yes
–
–
Between joists and in attic
Sheet metal
Mineral wool 30 mm
Yes
Mineral wool 30 mm
Yes
From tumble dryer
Sheet metal
Mineral wool 30 mm
No
Mineral wool 100 mm
No
Outdoor air
In kitchen
Sheet metal, accessible for
inspection
Armaflex AF3, 19 mm
Yes
–
–
Between joists and in attic
Sheet metal
Mineral wool 60 mm
Yes
Inside building’s vapour barrier
Only inside
Mineral wool 60 mm
building's vapour barrier
Supply air
Sheet metal
No requirements
Mineral wool at least 80 mm
No
Extract air
or equivalent.
Roof truss
Moisture barrier
Moisture barrier
Moisture barrier
Moisture barrier
The sheet must be bound
tightly to the duct.
Min thickness 10 cm.
Roof truss
Moisture barrier
Moisture barrier
Moisture barrier
Moisture barrier
The sheet must be bound
tightly to the duct.
Min thickness 10 cm.
Min thickness 10 cm.
Moisture barrier
Roof truss
Roof truss
Moisture barrier
Moisture barrier
Moisture barrier
Moisture barrier
The sheet must be bound
tightly to the duct.
Min thickness 10 cm.
Min thickness 10 cm.
Moisture barrier
Roof truss
