8
3.4 - Mounting the unit
Horizontal units should be mounted using the factory-installed
hangers. Proper attachment of hanging rods to building structure
is critical for safety (see Figs. 2 and 5). Rod attachments must
be able to support the weight of the unit. See Table 1 for unit
operating weights.
3.5 - Duct system
Size the duct system to handle the design airflow quietly.
NOTE: Depending on the unit, the fan wheel may have a
shipping support installed at the factory. This must be removed
before operating unit.
3.5.1 - Sound attenuation
To eliminate the transfer of vibration to the duct system, a flexible
connector is recommended for both discharge and return air
duct connections on metal duct systems. The supply and return
plenums should include internal duct liner of fibreglass or be
made of duct board construction to maximise sound attenuation
of the blower. Installing the water-source heat pump unit to un-
insulated ductwork in an unconditioned space is not recommended
since it will sweat and adversely affect the unit performance.
To reduce air noise, at least one 90
°
elbow could be included in
the supply and return air ducts, provided system performance is
not adversely impacted. The blower speed can also be changed
in the field to reduce air noise or excessive airflow, provided
system performance is not adversely impacted.
3.5.2 - Existing duct system
If the unit is connected to existing ductwork, consider the
following:
•
Verify that the existing ducts have the proper capacity to
handle the unit airflow. If the ductwork is too small, install
larger ductwork.
•
Check existing ductwork for leaks and repair as necessary.
NOTE: Local codes may require ventilation air to enter the
space for proper indoor air quality. Hard-duct ventilation may
be required for the ventilating air supply. If hard ducted ven-
tilation is not required, be sure that a proper air path is provi-
ded for ventilation air to unit to meet ventilation requirement
of the space.
Fig. 5 - Horizontal hanger bracket (factory-installed)
50RHE
Dimensions, mm
A
B
C
D
E
006-024
568
1095
619
1095
516
030, 036
568
1349
619
1349
518
042, 048
568
1577
619
1577
518
060
645
1806
695
1806
594
3.6 - Condensate drain
Slope the unit toward the drain at a 6.5 mm per 300 mm pitch
(see Fig. 6). If it is not possible to meet the required pitch, install a
condensate pump at the unit to pump condensate to building
drain.
Horizontal units are not internally trapped; therefore an external
trap is necessary. Install each unit with its own individual trap
and means to flush or blowout the condensate drain line. Do not
install units with a common trap or vent. For typical condensate
connections see Fig. 7.
NOTE: Never use a pipe size smaller than the connection.
3.6.1 - Venting
Install a vent in the condensate line of any application that may
allow dirt or air to collect in the line. Consider the following:
•
Always install a vent where an application requires a long
horizontal run.
•
Always install a vent where large units are working against
higher external static pressure and to allow proper drainage
for multiple units connected to the same condensate main.
•
Be sure to support the line where anticipated sagging from
the condensate or when “double trapping” may occur.
•
If condensate pump is present on unit, be sure drain
connections have a check valve to prevent back flow of
condensate into other units.
Fig. 6 - Horizontal unit pitch
Fig. 7 - Trap condensate drain
Note: Trap should be deep enough to offset maximum unit static difference.
A 102 mm trap is recommended.
B
A
C
E
D
D
Air handler
section
Compressor
section
Pitch toward
drain
Drain connection
Minimum pitch
25 mm per 3 m
of line
Open vent
To unit
See note
Drain plug
65 mm pitch
for drainage
