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68 UNT-SVX07A-EN
Maintenance
maintenance
procedures
Coil Maintenance
Keep coils clean to maintain maximum
performance. For operation at its highest
efficiency, clean the coil often during
periods of high demand or when dirty
conditions prevail. Clean the coil a
minimum of once a year to prevent dirt
buildup in the coil fins, where it may not
be visible.
Remove large debris from the coils and
straighten fins before cleaning. Remove
filters before cleaning.
Clean the coil fins using steam with
detergent, hot water spray and deter-
gent, or a commercially available
chemical coil cleaner. Be sure to rinse
coils thoroughly after cleaning.
WARNING
Hazardous Chemicals!
Coil cleaning agents can be either
acidic or highly alkaline. Handle
chemical carefully. Proper handling
should include goggles or face shield,
chemical resistant gloves, boots,
apron or suit as required. For
personal safety refer to the cleaning
agent manufacturer’s Materials
Safety Data Sheet and follow all
recommended safe handling
practices. Failure to follow all safety
instructions could result in death or
serious injury.
Inspecting and Cleaning Coils
Coils become externally fouled as a
result of normal operation. Dirt on the
coil surface reduces it’s ability to transfer
heat that can result in comfort problems,
increased airflow resistance and thus
increased operating energy costs. If the
coil surface dirt becomes wet, which
commonly occurs with cooling coils,
microbial growth (mold) may result,
causing unpleasant odors and serious
health-related indoor air quality
problems.
Inspect coils at least every six months or
more frequently as dictated by operating
experience. Cleaning frequently is
dependent upon system operating
hours, filter maintenance, and efficiency
and dirt load. Follow the suggested
methods in the following paragraphs.
Steam and Hydronic Coil Cleaning
Procedure
1. Disconnect all electrical power to the
unit.
2. Don the appropriate personal
protective equipment (PPE).
3. Access both sides of the coil.
4. Use a soft brush to remove loose
debris from both sides of the coil.
5. Use a steam cleaning machine,
starting from the top of the coil and
working downward. Clean the leaving
air side of the coil first, then the
entering air side. Use a block-off to
prevent steam from blowing through
the coil and into a dry section of the
unit.
6. Repeat step five as necessary.
Confirm that the drain line is open
following completion of the cleaning
process.
7. Allow the unit to dry thoroughly before
putting the system back into service.
8. Straighten any coil fins that may be
damaged with a fin rake.
9. Replace all panels and parts and
restore electrical power to the unit.
Winterizing the Coil
Make provisions to drain coils that are
not in use, especially when subjected to
freezing temperatures.
To drain the coil, blow the coil out with
compressed air. Next, fill and drain the
tubes with full-strength ethylene glycol
several times. Drain the coil as com-
pletely as possible.
CAUTION
Coil Freeze-up Damage!
Failure to properly drain and vent
coils when not in use during freezing
temperatures may result in coil
freeze-up damage.
Figure M-MP-3. To remove the main drain
pan on vertical fan-coil units, disconnect
the clips holding the pan to the fanboard.
Figure M-MP-4. To remove the main drain
pan on horizontal fan-coil units, peel the
insulation from the edges of the pan’s
underside to access the mounting screws.
clips hold drain pan in place
mounting screws