AAON RQ-006 - Manual (Page 65)

65
Figure 30 - Evaporator Coil Access
Remove screws attaching filter rack to the
evaporation coil at the front and back of the
coil. It may be necessary to remove the
economizer assembly (if equipped) to access
the screws at the back.
Slide the evaporator coil straight out of the
unit.
It may be necessary to make a vertical cut in
the front flange of the drain pan on either
side of the coil and bend the flange down
between the cuts to remove the evaporator
coil.
Reinstallation
Slide the new coil into the unit through the
notch cut in the front of the drain pan.
Re-bend the cut flange back to the original
position,
then seal the cuts with
polyurethane caulking.
Attach the filter at the front and back of the
evaporation coil. Reinstall economizer
assembly if necessary.
Connect the suction and liquid copper
connections to the evaporator coil. Reinstall
the TXV bulb on the suction line.
Evacuate the refrigerant system. Weigh in
the nameplate refrigerant charge.
See Adjusting Refrigerant Charge section to
check for proper sub-cooling and superheat
of the refrigerant systems.
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage.
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow. If unable to back wash
the side of the coil opposite of the coils
entering air side, then surface loaded fibers
or dirt should be removed with a vacuum
cleaner. If a vacuum cleaner is not available,
a soft non-metallic bristle brush may be
used. In either case, the tool should be
applied in the direction of the fins. Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins.
Use of a water stream, such as a garden
hose, against a surface loaded coil will drive
the fibers and dirt into the coil. This will
make cleaning efforts more difficult. Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse.
A
monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides, dirt, and debris. It is very
important
when rinsing, that water
Electric shock hazard. Shut off all
electrical power to the unit to avoid
shock hazard or injury from rotating
parts.
WARNING