AAON RN Series Installation Operation & Maintenance page 80

2. Adjust purge sector to the specified
angle.
3. Tighten the purge adjusting screws.
4. Turn the wheel by hand clockwise
(when viewed from pulley side) to
check for interference.
Polymer Wheel Check Purge Seal
If a purge is installed, check for a slight
interference fit between the seal and the face
of the wheel by sliding a piece of paper
("feeler gauge") between the seal and the
media a multiple locations along the purge
seal as you rotate the wheel slowly by hand
(clockwise when viewed from the pulley
side). Verify that the media slightly grabs the
paper during rotation.
If it is necessary to adjust a purge seal to the
face of the wheel, loosen the two or three
screws along the bearing beam and adjust to
the proper distance from the media surface.
Tighten the screws and retest the seal.
80
Polymer Wheel 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
Polymer 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