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21. 06. 13. Leaflet Number 671556
Installation and Maintenance
MRXBOX95B-WH1 Mechanical Ventilation with Heat Recovery & Summer Bypass
Any air intake terminal MUST be installed in accordance with the
appropriate regulation.
As a guide, the BS5440 series of British Standards deals with
this issue and currently states that an air intake must be at a
minimum distance of 300mm from a gas boiler balanced flue.
Installers are advised to be aware of the requirements of this
standard when installing ‘through the wall’ supply air ducting.
Similarly, supply and extract air grilles should be at least
300mm apart.
Figure 5a. Wet option.
Condensate pipe
connection to unit and
a typical example of
a “U” trap drainpipe.
Figure 5b. MVHR-DRAIN option.
Condensate drain, uninsulated drain
pipe with 10o fall running to SVP.
5
o
Drop
Collar
2.1 Condensate Drain
1.
Remove the front cover from the unit.
2. Insert the drain connector through the base of the unit from
outside. The condensate must be discharged under a water
level in a U-trap drainpipe or an alternative drain method
which acts as an airlock.
3. Ensure the drain connector forms a seal with the drain tray
applying sealant if necessary. This condensate discharge
connection is suitable for 21.5mm dia. overflow pipe.
Solvent cement should be used to make the joint.
4. If using a U-trap please ensure the U-trap has been filled to
a suitable level of water to avoid any air locks.
5. If the condensation pipe is fitted in an unheated space the
pipe should be in insulated to prevent freezing.
Nuaire recommend MVHR-DRAIN be used as the primary
condensate take-off. (see figure 5b/7a/7b).
2.2 Extract/input areas
The unit is designed to extract air from all wet rooms
e.g. bathroom, kitchen, en-suite, utility room (with sink).
WC’s do not need to be ventilated if openable windows
are fitted.
Supply air should be to all habitable rooms e.g. bedrooms and
lounge. Extract / input grilles should be adjustable valve types
(not supplied).
External grilles to have a minimum free area of 12,250 sq mm.
2.3 Ducting
Before commencing ducting installation reference should be
made to building regulations document “Domestic ventilation
compliance guide”. This document supports ADF2010 and
details installation, testing and commissioning of all ventilation
systems.
It is recommended that rigid ducting be used it all times.
Flexible ducting has a very high resistance and it is impossible
to calculate how much resistance will be on a system if used.
If used the flexible ducting must be kept to a minimum and
should always be pulled taut. A maximum of 500mm should
be used on each leg.
To prevent condensation on the outside of the outside air inlet
duct and the air outlet duct from the MRXBOX95B-WH1, these
ducts should be insulated.
Ducting must be installed in such a way that resistance to
airflow is minimised. Bends should be kept to a minimum.
A minimum distance of 200mm between the appliance and
any bends in ductwork is recommended.
Ideally 125mm diameter or 204 x 60mm rectangular ducting
should be used. (Refer to dwelling design drawing, figure 7a
and 7b on page 4 for further information).
Ducting joints must be sealed with silicone type sealant and
shall be adequately and reliably fixed to the appliance.
2.4 Ventilation flow rates
Table 1.
ADF2006 / 2010 – Extract ventilation rates
Room
Min high rate
Min low rate
Kitchen
13 l/s
Utility room
8 l/s
Bathroom
8 l/s
Sanitary
accommodation
6 l/s
Table 2.
Whole dwelling ventilation rates
Number of bedrooms in dwelling
1
2
3
4
5
Whole
13
17
21
25
29
dwelling
ventilation
rate l/s
1, 2
Notes:
1,
In addition, the minimum ventilation rate be should be not
less than 0.3 l/s per m
2
of internal floor area.
(This includes all floors, e.g. for a two-story building add the
ground and first floor areas).
2,
This is based on two occupants in the main bedroom and
a single occupant in all other bedrooms. This should be used
as the default value. If a greater level of occupancy is
expected add 4 l/s per occupant.
Total extract rate should
be at least the whole
dwelling ventilation rate
given in table 2.
