Any air intake terminal MUST be installed in accordance
with the appropriate regulation. Installers are advised to be
aware of the requirements of this standard when installing
‘through the wall’ supply air ducting.
2.1 Condensate Drain
1.
If using a U-trap please ensure the U-trap has been filled to a
suitable level of water to avoid any air locks.
2.
If the condensation pipe is fitted in an unheated space the pipe
should be in insulated to prevent freezing.
Figure 5a. Wet option.
Condensate pipe connection
to unit and a typical example
of a “U” trap drainpipe.
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) and WC’s.
Supply air should be to all habitable rooms e.g. bedrooms and lounge.
Extract / input grilles should be adjustable valve types (not supplied).
2.3 Ducting
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 300mm should be used on
each leg.
To prevent condensation on the exterior of the outside air inlet duct
and the air outlet duct from the unit, these ducts should be insulated
with material having a thermal resistance of >0.625m
2
K/w.
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 200mm diameter or 204 x 60mm
rectangular ducting should be used.
Ducting joints must be sealed with silicone type sealant and shall be
adequately and reliably fixed to the appliance.
2.4 Ventilation flow rates
Flow rates applicable to local market. Meets EPBD
requirements / EN308 tested.
2.5 Handing
The unit may be handed to switch the supply and extract spigot
positions, this can be done by following the steps below and are
shown in fig. 6.
Note: This process should only be carried out by a competent and
qualified person.
Step 1.
Remove the front cover and inner panel followed by the rear
panel to gain access to the inside of the unit
Step 2.
Partially pull out the metal tray to access the circuit board
and cable connections. All connections are required to be
disconnected and although assistance has been given to allow correct
reconnection please familiarise yourself with the layout before doing
so. Once all connections are disconnected the PCB tray can then be
fully removed, at this point the cables should be pulled through to the
other side of the unit. Then slide the PCB tray partially into the unit
ensuring the stand offs are on the side the front cover is going to be
fixed and that no cables are trapped. All cables can then be
re-connected to the PCB as per the original arrangement, note the
following cables have been tagged with a cable tie approximately
25mm from its termination point for identification as there are two
identical components. These are supply control cables, supply power
cables, TH1 and SWL1.
Once complete the PCB tray can be slid in the remainder of the way.
Step 3.
The filter should be reversed so the pull tab is at the side the
front cover is to be attached
Step 4.
The panels and cover removed in step 1 can then be
re-assembled to the opposing sides that they were removed, care
should be taken to ensure a good seal is achieved.
Figure 6. Unit handing view.
Figure 7. Airflow through unit in handed configuration.
2
27. 11. 17. Leaflet number 671617
Installation and Maintenance
MRXBOX95B-450 WC and MRXBOX95B-450
Figure 5b. MVHR-DRAIN option.
Condensate drain, uninsulated
drain pipe with min 5
o
fall running
to soil vent pipe.
Min 5
o
Drop
Collar
PCB
Front cover
Inner panel
Filter x 2
Rear panel
PCB tray
Exhaust air from
house to outside
Supply air
to house
Extract air
from house
Intake air
from outside
