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Installation Concerns
The RT will most often be installed on a rooftop but
in some cases it may be preferable to install the unit
at ground level beside the building, or even indoors.
This portion of the IOM applies directly to roof top
installations but most of the concerns remain the
same regardless of where the unit is installed.
Determine the best location, taking into consideration
proper air movement around the unit, proper
support of the unit and space around the unit for
periodic maintenance. Refer to architect / engineer's
instructions in the plans and specifications. Verify the
load bearing capacity where the unit is to be installed
and make certain that supporting structural members
will not conflict with openings needed for ductwork.
The RT must be elevated to isolate it from certain
weather/temperature conditions and to permit proper
installation of a condensate P trap and drain. Some
installations will use FHP model GKD roof curb
and an installation manual is included with it. It is
preferable that the GKD roof curb be installed prior to
installation of roofing membrane so that the curb can
be properly flashed. If the owner chooses to fabricate
a base in the field from materials supplied by others,
observe all area building codes and use industry Best
Practices to accomplish proper unit support and
elevation. See also "Rail Installations" in this manual.
If more than one unit is to be installed, make certain
that the discharge air from one unit is not directed
toward the outdoor air intake of any other unit.
Clearance for exhaust air and return air ducts may
be accomplished either by cutting individual duct
openings or by opening the entire space within the
roof curb unit. If the entire space within the curb is
opened, higher radiated sound levels may result.
Whenever supply or warm air ducts pass through
a combustible roof, clearance of at least one inch
(25 mm) must be maintained between the outside
surfaces of the ductwork and any combustible
materials in accordance with NFPA Standard 90.
Installation
The system design and installation should follow
accepted industry Best Practices, such as described
in the ASHRAE Handbook. Adequate space should
be left around the unit for piping coils and drains,
filter replacement, and maintenance. Sufficient space
should be provided on the side of the unit for routine
service and component removal should that become
necessary.
See Service Clearances/Access Panel Locations
section for more details.
Unit Weights and Recommended Roof
Opening
Exhaust
Intake
Unit Size
U
RT-20
46
RT-45
54
RT-55
65
RT-90
85
All dimensions are in inches. Unit weights assume rooftop
configuration with weatherhoods, filters, outdoor air
damper, six row DX coil, integral condensing section and
an indirect gas-fired furnace.
Position the unit roof opening such that the supply
discharge and exhaust inlet of the unit will line up
with the corresponding ductwork. Be sure to allow
for the recommended service clearances when
positioning opening (see Service Clearances).
Do not face the outdoor air intake of the unit into
prevailing wind and keep the intake away from any
other exhaust fans. Likewise, position the exhaust
discharge opening away from outdoor air intakes of
any other equipment.
Model RT Energy Recovery Unit
V
U
Supply
Discharge
1/2 inch
1/2 inch
1/2 inch
Approximate
V
Weight (pounds)
37
2150
39
3500
47
4450
49
5300
9
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