5
15. 03. 21. Document Number 671838
Nuaire |
Western Industrial Estate
|
Caerphilly
|
CF83 1NA
|
nuaire.co.uk
MRXBOXAB-ECO4-1Z
Installation Manual
3.8 ADF 2010 Ventilation Calculations Design of MVHR
Systems
The MVHR system has been sized for the winter period. Additional
ventilation may be required during the warmer months and it has
been assumed that the provisions for purge ventilation (e.g. openable
windows) could be used.
Step 1:
For any design air permeability, determine the whole dwelling
ventilation supply rate from
Whole Dwelling Ventilation Rates table.
As an alternative where the design air permeability is intended to be
more than (>) 5m3/(h.m2) 50 Pa, allow for infiltration for all dwelling
types by subtracting from the whole dwelling ventilation supply rate
from Whole Dwelling Ventilation Rates table;
0.04 x gross internal
volume of the dwelling heated space (m3).
Step 2:
Calculate the whole dwelling extract ventilation rate by
summing the individual room rates for ‘minimum high rate’
from ADF
2010 - Extract Ventilation Rates table.
(For sanitary accommodation only, as an alternative, the purge
ventilation provisions given in ADF 2010 can be used where security is
not an issue. In this case ‘minimum high extract rate’ for the sanitary
accommodation should be omitted from the step 2 calculation).
Step 3:
The required airflow rates are as follows:
•
The maximum whole dwelling extract ventilation rate (e.g. boost)
should be at least the greater of step 1 and step 2. Note that the
maximum individual room extract rate should be at least those
given in
ADF 2010 - Extract Ventilation Rates table.
•
The minimum air supply rate should be at least the whole building
ventilation rate found in step 1.
For Scotland refer to BRE Digest 398.
For further information refer to “Domestic Ventilation Compliance
Guide” www.planningportal.gov.uk/buildingregulations/approved
documents/partl/compliance.
3.8.1 Pre Commissioning MRXBOX MVHR Units
MRXBOX units are designed to ventilate the whole dwelling and must
not be used during site construction or the clean-up period. Cement
and plaster dust can be abrasive and can affect fan performance
and reliability. Please ensure that the filters are checked prior to
commissioning to ensure there is no build-up of dust or debris.
While the property is drying out, very high moisture levels are likely
to occur. Therefore it is advisable that if the installation and building
works are complete the unit is left running. If the building works are
not complete please close the air valves or cover up the air valves to
prevent condensation forming in the ductwork and the MRXBOX unit
due to natural migration of warm air.
3.9 Dimensions (mm)
10
Unit Dimensions
789
14
56
52
191
290
200
485
672
If ancillary distribution box MRXBOX-DB4 is to be used
refer to documentation supplied with MRXBOX-DB4
for additional infomation as requirements will differ.
Condensate drain position for standard hand
configuration. For opposite hand configuration,
position will be mirrored to other side.
