AAON HB-005 - Manual (Page 26)

26
7. Operation & Maintenance
General
Immediately following building occupancy, the air
conditioning system requires a maintenance schedule
to assure continued successful operation. A
maintenance program similar to the example given
below should be scheduled for routine maintenance of
this equipment in order to provide continued efficient
and reliable operation for the owner.
Maintenance Schedule
One week after start-up:
− Check heating and cooling functions.
− Check cycling of compressor and fan. Correct
unusual cycling.
Monthly:
− Inspect evaporator, and condenser coils. Clean if
dirty, or obstructed in any way.
− Inspect air filters. Replace if required.
Annually:
− Clean the condenser, and evaporator coils with
steam, or a non-corrosive coil cleaner.
− Check refrigerant pressures and temperatures
every spring, and correct unusual operation.
Cooling
Coils should be inspected and cleaned at least once
per year to ensure there is no obstruction to airflow.
Evaporator Coil
Dirty evaporator coils will eventually freeze up, and
often result in a time consuming, and expensive
service call. Clean filters will help to prevent dirt from
accumulating on the evaporator; however the
evaporator should be cleaned annually with a soft
bristled brush, and/or a non-corrosive coil cleaning
solution.
Condenser Coil
One of the most overlooked maintenance
requirements is the need to keep air moving freely
across air-cooled condensing coils. Dirty condensers,
like evaporators, can significantly increase cooling
costs during the year. As a minimum, clean the
condenser coil at the beginning of each cooling
season. It is preferable to use a medium pressure
water spray from the inside of the condenser cabinet
with a non-corrosive coil cleaning solution. TURN
OFF all power to the unit before cleaning.
Comb out any visible exterior fin damage to help
maintain unit efficiency.
Condenser Fan
Always check condenser fan blades to ensure
unobstructed, free rotation after manipulating the unit
cabinet in any way, and before turning power back on
to the condenser. Clean the fan blades if they are
dirty.
Blower Assembly
HB package units use direct drive, backward inclined
airfoil blower wheels that are non-overloading, very
efficient, and very easy to clean. There are no fan
belts or fan bearings to maintain.
Clean blower wheels are necessary to reduce
electrical use, maintain capacity and reduce stress on
the unit. The blower wheel and blower section need to
be inspected periodically, and cleaned of dust, or
debris.
To inspect and clean the blower; set thermostat to the
“OFF” position; turn the electrical power to the unit to
the “OFF” position at the disconnect switch.
Figure 26a, Blower Section