Specifications

-38-
3. Duct construction
4. Lifting method
Hook (as directly aligned
over the center of gravity
as possible.
6. Refrigerant charge
4.7
PRHG-8
Refrigerant
charge per circuit
(kg)
5.6
PRHG-10
PRHG-15 PRHG-20
2 × 4.7 2 × 5.6
5. Drain piping
The drain piping should have a drain trap.
A 70mm
B 2C
C 2XE. S. P
Drain trap
Drain piping
Note: ESP = External Static Pressure
Drain trap for condensate
The drain pipe
should extend
below this level.
A
B
C
Roof line
Roof curb
Roof curb
Duct
PRHG down flow unit
Insulation
Outdoor sideIndoor side
Duct connection with
a vertical air plenum
at PRHG side flow unit
Duct connection
at PRHG down flow unit
PRHG
side flow unit
Insulation
Roof curb
Roof line
Duct
Single duct
divider
Plenum
divider
Duct
Roof curb
Duct
Duct-work length 850 mm or more
The rain water come down from joint part.
So prevent rain water from entering the building.
(1) Series PRHG 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 PRHG 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.
When the unit is to be lifted and moved, attach ropes to the suspension
plates (4 pcs) provided on the top of the unit.
When the unit is lifted, it is center of gravity tends to shift the unit one side
and so balance, such as that in the figure below, should be attained.
The angles at which the ropes suspend the unit should be at least 60° at the
compressor end and at least 45° at the condenser end.
Care should be taken to avoid contact with the main unit while carrying.
An additional charge is unnecessary.
The table below shows the amount of the charge when the factory is shipped.
(1) The condensate drain fitting (R 1) is provided. The drain pipe can be led
out at the right side.
(2) The drain pipe must be provided with a trap on the outside of the unit and
also installed at an incline for proper drainage, as shown below.
(3) To prevent condensate formation and leakage, provide the drain pipe with
insulation to safeguard against sweating.
(4) Upon completion of the piping work, check that there is no leakage and
that the water drains off properly.