AAON M3-094 - Manual (Page 61)

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will help prevent dirty coils; however, coils
should still be cleaned at least annually by
an HVAC professional.
The coils should be cleaned using steam,
low-pressure water, low-pressure air, or a
non-corrosive coil cleaner.
Take care not to damage fins while cleaning.
High pressure water can damage fins.
Condensate drain pans should be inspected
often and cleaned at least annually to
maintain proper drainage and prevent the
spread of disease. Cooling coils are raised
off the drain pan to facilitate cleaning.
The drain and p-traps should also be
checked to prevent clogging. A clogged
drain will result in water backing up in the
drain pan and potentially damaging the unit
and the building.
Winterizing Coils
In some cases it may be necessary to
winterize water coils to prevent them from
freezing.
First completely drain the coils. There is a
drain located below the ‘water in’
connection and a vent connection located
above the ‘water out’ connection. Auxiliary
drain piping can also be added to exterior
water piping if yearly winterizing is
necessary.
After the coil is drained, fill with an
antifreeze solution using a circulating pump.
Then thoroughly drain.
Removing Coils
Coils on the M3 units can be removed from
either side of the unit. The coils are
independently supported so they can be
removed independently from either side of
the unit.
To remove a coil, first disconnect the water
piping from the coil. Remove the coil access
panel on the side from which the coil is to be
removed. Remove the screws connecting
coil end panel to the coil. Slide the coil
straight out onto a support that is at the same
level as the coil.
To replace the coil, the above procedure
should be reversed. The coil should first be
placed on a support that is at the same level
as the coil position in the unit. The coil
should then be slid straight into the unit.
The upper coil location has angles on both
the front and back side of the coil; the lower
coil has an angle on the downstream side of
the coil and guides on the upstream side. Be
sure that the coil is all the way up against the
front (downstream) side of the coil, this
should center the coil in the opening.
Push the coil all the way in so that the
return-bend side of the coil is between 1/8”
and 1/4” from the inside wall of the unit. For
cooling coils, be sure that the vertical
headers are entirely over the drain pan.
Screw the coil end panel to the coil using
self-tapping sheet metal screws.
When steam cleaning coils, be sure
area on both sides of coil is clear of
excess personnel.
WARNING
Take care that the coil is not dropped
or knocked over. This could damage
the coil fins, or cause a leak in the
coil.
CAUTION