3.0 Loft inspection
Check to ensure that the loft has adequate ventilation. Look for
ridge vents, tile vents, eaves vents and continuous air gaps etc.
making sure none are blocked. In older properties these vents may
not be provided. However, there should be enough ‘leakage’ to
accommodate the requirements of the unit. A useful way of
checking such lofts is to close the hatch, switch off the lights and
look for any daylight penetration. If you can see daylight it is
reasonable to assume that the loft has sufficient ventilation.
There may be occasions where a loft is so well sealed that additional
ventilation may have to be provided by the owner/occupier or the
unit installer.
This will not only assist the operation of the unit, but will help
prevent possible expensive structural damage caused by inadequate
air movement in the loft itself.
It should be noted that there cannot be too much ventilation into
the loft.
Additional checks should be carried out as follows:
Ensure that all water tanks are covered and sealed.
Check that all water pipes are lagged.
Ensure that any extract fans are discharging to outside
and not into the loft.
Check that the loft hatch is tightly sealed.
Ensure all holes in the ceilings are sealed i.e. ceiling
light fittings etc.
A visual inspection of flues or chimneys for leakage
in the loft should be carried out by the installer.
If leakage points are found, or if there is any doubts
regarding the same the installer should advise the
house owner/provider and seek instruction from them
before continuing with installation.
4.0 Siting the Diffuser
The diffuser has a unique air throw pattern and it must be located
correctly in the central hallway in single storey properties or in the
ceiling of the top floor landing on 2 or more storey dwellings.
As can be seen (Figure 2) the diffuser discharges air from all four
sides along the underside of the ceiling. The majority of the air is
discharged through the two longer open sides and it is vital that the
diffuser is positioned to ensure these two sides discharge the air
down the longest lengths of the hallway or landing.
Obstructions within 1m of the diffuser will cause a poor airflow
pattern and unacceptable draughts. Up to two sides of the diffuser
may be closed off using the foam strips supplied.
5.0 Fitting the Diffuser
Cut a circular hole 225mm diameter in the ceiling between two
joists. Position the diffuser frame and secure to the underside of
the ceiling with the 1
1/
2
” x 8 csk screws and plugs provided.
Attach the diffuser plate to the frame using the two 1” x 8 csk
screws and plugs provided. (See figure 3).
Where there is a requirement for maintaining fire rating of the ceiling
then the following alternative method of installing the diffuser using
a 200mm dia. spigot available from Nuaire and a
“Fireblock”
is
recommended. (See figure 4).
Designed to provide 1 hour of fire resistance in accordance with
BS476 Part 20 (1987) and ISO 834, this circular
“Fireblock”
is
available to fit snugly inside our standard 200mm dia. spigot.
(Part No. 011740).
Foam strips should also be used as required when this method of
installing the diffuser is used.
Installation and Maintenance
Low Energy Positive Input Ventilation Unit
Figure 2.
Note: Smoke Detectors
It is important that any open side of the diffuser is not
positioned within 1m of a smoke detector.
If the diffuser cannot be repositioned, up to two sides
of the diffuser may be closed off using the foam strips
supplied so that the open sides face a minimum 1.5m
unobstructed path away from the detector.
As an alternative to the aforementioned, a smoke detector
maybe fitted directly onto the underside of the diffuser.
Figure 3.
2
Leaflet Number 671347 October 2007
Figure 4.
