AAON RN-140 - Manual (Page 66)

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adsorb and desorb moisture and also build
up so as to reduce airflow.
In a reasonably clean indoor environment
such as a school or office building,
measurable reductions of airflow or loss of
sensible (temperature) effectiveness may not
occur for several years. Measurable changes
in latent energy (water vapor) transfer can
occur in shorter periods of time in
applications such as moderate occupant
smoking
or cooking facilities. In
applications experiencing unusually high
levels of occupant smoking or oil based
aerosols such as industrial applications
involving the ventilation of machine shop
areas for example, annual washing of energy
transfer may be necessary to maintain latent
transfer efficiency. Proper cleaning of the
energy recovery wheel will restore latent
effectiveness to near original performance.
To clean, gain access to the energy recovery
wheel and remove segments. Brush foreign
material from the face of the wheel. Wash
the segments or small wheels in a 5%
solution of non-acid based coil cleaner or
alkaline detergent and warm water.
Soak in the solution until grease and tar
deposits are loosened (Note: some staining
of the desiccant may remain and is not
harmful to performance). Before removing,
rapidly run finger across surface of segment
to separate polymer strips for better cleaning
action. Rinse dirty solution from segment
and remove excess water before reinstalling
in wheel.
Air Seals
Four adjustable diameter seals are provided
on each cassette to minimize transfer of air
between the counter flowing airstreams.
To adjust diameter seals, loosen diameter
seal adjusting screws and back seals away
from wheel surface. Rotate wheel clockwise
until two opposing spokes are hidden behind
the bearing support beam. Using a folded
piece of paper as a feeler gauge, position
paper between the wheel surface and
diameter seals.
Adjust seals towards wheel surface until a
slight friction on the feeler gauge (paper) is
detected when gauge is moved along the
length of the spoke. Retighten adjusting
screws and recheck clearance with “feeler”
gauge.
Wheel Drive Components
The wheel drive motor bearings are pre-
lubricated and no further lubrication is
necessary.
The wheel drive pulley is secured to the
drive motor shaft by a combination of either
a key or D slot and set screw.
The set screw is secured with removable
locktite to prevent loosening. Annually
confirm set screw is secure. The wheel drive
belt is a urethane stretch belt designed to
provide constant tension through the life of
the belt. No adjustment is required. Inspect
the drive belt annually for proper tracking
and tension. A properly tensioned belt will
turn the wheel immediately after power is
applied with no visible slippage during start-
up.
Installation Considerations
Energy recovery cassettes are incorporated
within the design of packaged units,
packaged air handlers and energy recovery
Do Not use acid based cleaners,
aromatic
solvents, steam or
temperatures in excess of 170°F;
damage to the wheel may occur!
CAUTION