AAON RN-140 - Manual (Page 64)

64
proper operation efficiency and building
occupant comfort.
Normal maintenance requires periodic
inspection of filters, the cassette wheel,
drive belts, air seals, wheel drive motor, and
its electrical connections.
Wiring diagrams are provided with each
motor. When wired according to wiring
diagram, motor rotates clockwise when
viewed from the shaft/pulley side.
By carefully reviewing the information
within this section and following the
instructions, the risk of improper operation
and/or
component damage will be
minimized.
It is important that periodic maintenance be
performed to help assure trouble free
operation.
Initial Mechanical Check and Setup
Outdoor units equipped with outside air
intake will have an outside air hood. The
outside air hood must be opened prior to unit
operation.
Outdoor air intake adjustments should be
made according to building ventilation, or
local code requirements.
After the unit installation is complete, open
the cassette access door and determine that
the energy wheel rotates freely when turned
by hand. Apply power and observe that the
wheel rotates at approximately 30 RPM. If
the wheel does not rotate when power is
applied, it may be necessary to readjust the
“diameter air seals”.
Air Seal Adjustments
Pile type air seals across both sides of the
energy wheel diameter are factory adjusted
to provide close clearance between the air
seal and wheel. Racking of the unit or
cassette during installation, and/or mounting
of the unit on a non-level support or in other
than the factory orientation can change seal
clearances. Tight seals will prevent rotation.
Cross Section of Air Seal Structure
Wheel to Air Seal Clearance
To check wheel to seal clearance; first
disconnect power to the unit, in some units
the energy recovery wheel assembly can be
pulled out from the cabinet to view the air
seals. On larger units, the energy recovery
wheel may be accessible inside the walk-in
cabinet.
A business card or two pieces of paper can
be used as a feller gauge, (typically each
.004” thick) by placing it between the face
of the wheel and pile seal.
Using the paper, determine if a loose slip fit
exist between the pile seal and wheel when
the wheel is rotated by hand.
To adjust air seal clearance, loosen all seal
plate retaining screws holding the separate
seal retaining plates to the bearing support
channels and slide the seals plates away
from the wheel. Using the paper feeler
gauge, readjust and retighten one seal plate
at a time to provide slip fit clearance when
the wheel is rotated by hand.