AAON M2-036 - Manual (Page 74)

74
Maintenance
(See back of the manual for maintenance
log.)
One week after start-up:
− Check operating pressures.
− Adjust belt tension on all fan drives.
− Check filters for cleanliness. Measure
pressure loss if applicable. Replace if
necessary.
− Check cycling of compressors, fans, and
valves. Correct unusual cycling.
Monthly:
− Lubricate bearings if operating
continuously at 1500 rpm, or higher, or
in other extreme conditions.
− Check cleanliness of filters and replace
if necessary.
− Check cooling coil drain pan to assure
proper drainage.
− Inspect all coils. Clean if dirty or
obstructed in any way.
Quarterly:
− Lubricate bearings if operating at 1000
rpm, or less, and in temperatures less
than 150
°F, or other extreme conditions.
− Check damper operation for freedom of
movement. Correct any binding that
may occur.
− Check belts and pulleys on fan drives for
tension and unusual wear.
− Check operation of heating and cooling
sections.
− Check inlet and outlet air temperatures.
Annually:
− Clean the coils with steam or non-
corrosive coil cleaner.
− Clean the drain line, “P” trap, and
condensate pan.
− Check refrigerant pressures and
temperatures every Spring.
− Check heating section every Fall. Check
all electrical connections for tightness
and check heater elements for
indications of overheating.
Fan Assembly
M2 Series units use backward curved fan
wheels which are non-overloading, energy
efficient and easy to clean. Cleaning the
wheels is necessary to reduce electrical use,
maintain capacity, and reduce stress on the
unit. The wheel and fan 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. Clean the
assembly. Check the bearings. Inspect the
belt condition and tightness. Check screws
for tightness. Rotate blower wheels while
listening closely to each bearing to check for
noise or roughness in the bearing, which can
indicate a failing bearing.
Bearings
AAON uses pre-lubricated bearings, and
bearings that have been sized for an average
failure rate of 50% after 200,000 hours, or
22.8 years, of operation (see heading
“Lubrication” in this section for more
information). The bearing sizing tables
below are based on rotational speeds and
radial loading. However, the alignment of
the bearing to the shaft and the security of
the bearing inner race to the shaft will
greatly affect bearing life. Even though the
manufacturer is responsible for bearing
tolerances and mounting design, the
servicer is advised to regularly check the
security of the bearing locking system.