Coil Winterization; Moisture Purge Cycle - Trane UCCA Installation, Operation And Maintenance Manual

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.
To clean refrigerant coils:
1. Disconnect all electrical power to the unit.
2. Wearing the appropriate personal protective
equipment, use a soft brush to remove loose debris
from both sides of the coil.
3. Install a block-off to prevent spray from going through
the coil and into a dry section of the unit and/or system
ductwork.
4. Mix a high-quality coil cleaning detergent with water
according to the manufacturer's instructions.
Note: If the detergent is strongly alkaline after mixing (PH
8.5 or higher), it must contain an inhibitor. Follow
the cleaning solution manufacturer's instructions
regarding the use of the product.
5. Place the mixed solution in a garden pump-up sprayer
or high-pressure sprayer. If a high pressure sprayer is
to be used:
– Maintain minimum nozzle spray angle of
15 degrees.
– Spray perpendicular to the coil face.
– Keep the nozzle at least 6 inches from the coil.
– Do not exceed 600 psi.
6. Spray the leaving air side of the coil first, then the
entering air side.
7. Thoroughly rinse both sides of the coil and the drain
pan with cool, clean water.
8. Repeat steps 6 and 7 as necessary.
9. Straighten any coil fins damaged during the cleaning
process.
10. Confirm the drain line is open following the cleaning
process.
11. Allow the unit to dry thoroughly before putting it back
into service.
12. Replace all panels and parts and restore electrical
power to the unit.
13. Be careful any contaminated material does not contact
other areas of the unit or building. Properly dispose of
all contaminated materials and cleaning solution.
CLCH-SVX009A-EN

Coil Winterization

Water coil winterization procedures consist primarily of
draining water from the coil before the heating season.
Trane recommends flushing the coil with glycol if coils will
be exposed to temperatures below 35 degrees.
NOTICE:
Coil Freeze-up!
Drain and vent coils when not in use. Trane
recommends glycol protection in all possible freezing
applications. Use a glycol approved for use with
commercial cooling and heating systems and copper
tube coils. Failure to do so could result in equipment
damage.
Install field-fitted drains and vents to permit winterization
of coils not in use and to assist in evacuating air from the
water system during startup. If draining is questionable
because of dirt or scale deposits inside the coil, fill the coil
with glycol before the heating season begins.
Note: On many unit sizes, there are multiple coils in the
coil section. Be sure to winterize all coils in a given
coil section.
To winterize hydronic coils:
1. Remove the vent and drain plugs.
2. Blow the coil out as completely as possible with
compressed air.
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.

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
shutdown 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 handler.
Routine Maintenance
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