Routine Maintenance
CLCH-SVX013B-EN 75
3. Fill and drain the coil several times with full strength
glycol so that it mixes thoroughly with the water
retained in the coil.
4. Drain the coil out as completely as possible.
5. To ensure no water remains in
the coil, do not replace
the vent and drain plugs until the coils are put back into
service.
Note: Use care in removing header plugs from Type P2,
P4
, and
P8 coils. Over-torquing may result in
twisted tubes.
Moisture Purge Cycle
By it’s very nature, any HVAC unit with a cooling coil serves
as a dehumidifier, reducing the surrounding air’s ability to
hold water vapor as its temperature falls. This normally
doesn’t present a problem when the unit is running.
However, when the fan stops, water vapor condenses on
the cold metal surfaces inside the air handler and remains
there until the air warms sufficiently to re-evaporate it.
This damp, dark environment—though temporary—can
encourage the growth of mold, mildew, and other
microbial contaminants.
Providing a moisture purge cycle 15 to 30 minutes after
shutdow
n disperses the cold,
humid air inside the air-
handling system more evenly throughout the building.
This four-step cycle:
• Closes the outdoor air dampers.
• Turns off the cooling coil.
• Opens any variable-air-volume
terminals connected to
the air handle
r.
• Operates the supply fan for 10 to 15 minutes.
Air movement discourages w
ater condensation and
hastens re-evaporation of any condensate that does
happen to form. This simple preventative measure
effectively combats microbial growth and curbs moisture-
related deterioration of air-handling components.
Drain Pans
WARNING
Hazardous Chemicals!
Coil cleaning agents can be either acidic or highly
alkaline and can burn severely if contact with skin
occurs. Handle chemical carefully and avoid contact
with skin. ALWAYS wear Personal Protective Equipment
(PPE) including 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.
WARNING
No Step Surface!
Do not walk on the sheet metal drain pan. Walking on
the drain pan could cause the supporting metal to
collapse, resulting in the operator/technician to fall.
Failure to follow this recommendation could result in
death or serious injury.
The condensate drain pan and d
rain li
ne must be checked
to assure the condensate drains as designed. This
inspection should occur a minimum of every six months or
more often as dictated by operating experience.
If evidence of standing water or condensate
overflow
exis
ts, identify and remedy the cause immediately. Refer
to “Troubleshooting,” p. 79 for possible causes and
solutions.
To clean drain pans:
1. Disconnect all electrical power to the unit.
2. Wearing the appropriate personal protective
eq
uipmen
t, remove any standing water.
3. Scrape solid matter off of the drain pan.
4. Vacuum the drain pan with a vacuum device that uses
hi
gh-effi
ciency particulate arrestance (HEPA) filters
with a minimum efficiency of 99.97 percent at
0.3 micron particle size.
5.
Thoroughly clean any contaminated area(s) with a
mi
ld bleach and water solution or an EPA-approved
sanitizer specifically designed for HVAC use.
6. Immediately rinse the affected surfaces thoroughly
with
fresh water and a fresh spong
e to prevent
potential corrosion of metal surfaces.
7. Allow the unit to dry completely before pu
tting it back
into service.
8. Be careful any contaminated m
aterial
does not contact
other areas of the unit or building. Properly dispose of
all contaminated materials and cleaning solution.
Fans
WARNING
Rotating Components!
The following procedure involves working with rotating
components. Disconnect all electric power, including
remote disconnects before servicing. Follow proper
lockout/ tagout procedures to ensure the power can
not be inadvertently energized. Secure rotor to ensure
rotor cannot freewheel. Failure to secure rotor or
disconnect power before servicing could result in
rotating components cutting and slashing technician
which could result in death or serious injury.
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