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Subject to Technical Modifications of Combi 185 S/LS
Ducting system
It is recommended that the ducting system is made from
spirally flanged pipes using fittings with a rubber ring seal
so that an airtight and durable ducting system is achieved.
In order to achieve a noise level from the unit which satis-
factorily low, silencers should always be mounted on the
supply air and exhaust air ducting systems between the
unit and the first air intake and exhaust valves.
It is recommended that air speeds in the ducting are kept
sufficiently low so that noise is not generated by the air
intake and exhaust valves.
When air roof-cowls/air gratings for air discharged to the
outside are established, it must be avoided that the two air
streams short circuit so that the discharged air is drawn
back in.
It is recommended to place roof-cowls/ air gratings on the
northern or eastern side of a building in order to achieve
maximum comfort in the dwelling.
Minimum distance between roof-cowls/air gratings is
3 metres.
Insulation of ducts in cold
spaces
In order to exploit the unit’s high recovery potential
(efficiency), it is necessary to insulate the ducts correctly.
Genvex recommends as follows:
Supply air and extract air ducts
To minimise heat losses from the duct system in cold loft
spaces, the supply and extract ducts must be insulated
with a minimum of 100 mm insulation. If insulation form
alternative A is used, it is recommended that it is execut-
ed with two layers of 50 mm lamella mats with paper or
foil externally and with staggered joints between the two
layers. If the ducts are laid on the rafter foot, alternative
B may be used. The insulation must always be tightly
packed round the ducts.
Fresh air and exhaust air ducts
It is recommended that fresh air and escaping ducts
are insulated with a minimum of 50 mm insulation. The
fresh air duct is insulated to prevent warm air in the loft in
summer from heating up the fresh air. Take care to seal
the termination where the escaping duct is led through
the roof or through the gable end, in order to avoid
condensation damage.
Refer to your local distributor for guidance on national
insulation directives.
Duct insulation, alt. A
Duct insulation, alt. B
Faulty duct insulation
