Specifications

72
2. Installation
Of The Unit.
(1) The figure shows the use of the roof curb available for
mounting these units.
(2) The curb should be sealed and fixed to the roof by
weather stripping. A suggested means of sealing the
unit and roof curb is shown below.
3. Duct Construction.
(1) Series MRT side flow units are equipped with horizontal supply and
return air openings. Duct connection to the unit should be made with
duct flanges and secured directly to the air openings with flexible duct
connectors to avoid normal noise transmission.
(2) For vertical air supply, a field supply plenum should be used.
The figure below shows the recommended method for duct connection.
(3) Series MRT down flow units are equipped with vertical supply and return
air openings. Duct connection to the unit should be made with duct
flanges to avoid normal noise transmission.
(4) To prevent air leakage, all duct seams should be taped.
Ducts run in air spaces that are not air-conditioned must be insulated
and provided with a vapor barrier.
Ducts exposed to the outside must be weather proofed. For quiet
operation, we recommend that the insulation on the supply duct be
placed inside, lining the duct.
(5) Where ducts from the outside enter a building, the duct openings
in the building should be sealed with weather stripping to prevent
rain, duct, sand, etc. from entering the building.
(6) Fans will not accept any external resistance to airflow and what
provision is available if ductwork is to be fitted to the external fans.
(7) Correctly sized filters must be fitted and there is no provision within
the unit, however the filters may be installed in the return air.
(8) Duct earth wiring must be connected, refer to term 4 (outline drawing)
about earth point.
In case of down flow, we must use accessory screw attached on
control box cover.
MRT250/300 A/AR
Duct connection with
a vertical air plenum
at MRT side flow unit
Duct connection at
MRT down flow unit