AAON RN Series, Installation Operation & Maintenance, Page: 65 / 136

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2. Remove the belt tensioner bolt
completely, as indicated by the arrow
below.
3. At this point the motor mount can be
slid toward the wheel, and the belt
can be removed.
4. Once the belt is removed the motor
and mount can be lifted out. Make
sure the wires to the motor are loose.
DX Cooling
Set unit controls to cooling mode of operation
with supply fans on. Check the fan for correct
operating direction, amperage and voltage.
Check
compressor operation, rotation,
amperage and voltage to the unit nameplate
(check the amperage on the load side of the
compressor contactor).
Condensate Drain Pans
Drain pans will have moisture present and
require
periodic cleaning to prevent
microbial growth. Cleaning of the drain pans
will also prevent any possible plugging of the
drain lines and overflow of the pan itself.
Cleaning of the drain pans and inside of the
unit must be done only by qualified service
technician.
Brazed Plate Heat Exchanger Cleaning
Because of a normally high degree of
turbulence in brazed plate heat exchangers,
for many applications the heat exchanger
channels are self cleaning. For applications
that are not self cleaning (i.e. hard water at
high temperatures, etc.) or applications where
additional cleaning is desired, it is possible to
clean the brazed plate heat exchanger by
circulating a cleaning liquid.
Use a tank with weak acid, 5% phosphoric
acid (H
3
PO
4
) or, if the exchanger is
frequently cleaned, 5% oxalic acid (H
2
C
2
O
4
).
Pump the cleaning liquid through the
exchanger. For optimum cleaning, the
cleaning solution flow rate must be a
minimum of 1.5 times the normal flow rate,
preferably in a back-flush mode. After
cleaning, the heat exchanger must be rinsed
with clean water. A solution of 1-2% sodium
hydroxide (NaOH) or sodium bicarbonate