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quired. Inspect the drive belt annually for proper tracking and ten-
sion. A properly tensioned belt will turn the wheel immediately af-
ter power is applied with no visible slippage during start-up.
Cleaning Unit Interior/Exterior
Unit interior/exterior panels should be wiped down using a damp
soft cloth or sponge with a mixture of warm water and a mild
detergent. Avoid using an abrasive cleaner, as damage to the paint
could occur resulting in rust and corrosion. Chemicals such as
paint thinners can damage the painted panels and should be
avoided.
CAUTION
Avoid washing unit electrical devices such as motors, starters,
electric heater control boxes, damper/valve actuators, sensors,
switches, relays, etc. as serious personal injury or damage to
the device could result.
Coil Cleaning
Chilled water, hot water, steam, and direct expansion coils must be
cleaned regularly to maintain peak performance. Dirty coils can
contribute to loss of cooling or heating capacity and efficiency, in-
creased operating costs, and compressor problems on direct ex-
pansion systems. Dirt, grease, and other oils can also reduce the
wettability of the coil surfaces, which can result in moisture blow-
off from cooling coils and resulting water leakage problems. If the
grime on the surface of the coils becomes wet, which commonly
occurs with cooling coils, microbial growth (mold) can result,
causing foul odors and health related indoor air quality problems.
Coils can become dirty over a period of time, especially if air filter
maintenance is neglected. Coils should be inspected regularly and
cleaned when necessary. If coil fins become dirty, pressure clean
with hot water and detergent or a commercial coil cleaner. Be sure
to rinse coils thoroughly after cleaning with chemical cleaners.
CAUTION
Follow all directions provided with the chemical cleaners to
avoid personal injury, injury to others, and/or coil damage.
Chemical coil cleaners may contain corrosive or harmful
agents.
1. Disconnect all electrical power to the air-handling unit,
including any separate power supplies for unit mounted
controls (actuators, sensors, etc.).
2. Wear the appropriate protective clothing (eyewear,
gloves, etc.).
3. Ensure there is sufficient access to the coil.
4. Use a vacuum with a soft tip brush to remove any dust
and loose debris from both sides of the coil.
5. Clean the leaving airside of the coil first, then the entering
airside, starting from the top of the coil and working
downward. Apply a mild non-foaming commercial coil
cleaner or detergent using a garden type sprayer. Rinse
coil
gently
with
high-pressure sprays, which can cause damage to coil
fins. Use a block-off plate to prevent the water or chemi-
cal cleaner from blowing through the coil and into a
clean, dry section of the unit. Confirm that the condensate
drain line is free of debris during and following the coil
cleaning process. Excess water from cleaning may result
in flooding the unit as well as causing damage to the
building if drain is plugged. If coil section does not have a
drain pan, it is recommended that the coil be removed pri-
or to cleaning.
6. Repeat Steps 1 through 5 as necessary.
7. Allow the coil to dry thoroughly before placing the sys-
tem back into operation. A clean dry cloth may be used to
clean
warm
water,
avoiding
wipe down the interior panels before placing the unit in
operation.
8. Using a fin rake, straighten any coil fins that may have
been bent or damaged during the cleaning process.
9. Replace all panels and parts that may have been removed
prior to cleaning and restore electrical power to the unit.
10. Use caution to assure that no contaminated materials con-
tact other areas of the unit or building. Properly dispose of
any polluted materials and cleaning fluids.
Winter Shutdown
It is recommended that auxiliary drain piping be added to coil pip-
ing if yearly winterizing of coils is anticipated. This auxiliary pip-
ing should be located at the highest and lowest point on the respec-
tive header connection for each coil.
ANTIFREEZE METHODS OF COIL PROTECTION
1. Close coil water supply and return valves.
2. Drain coil as follows:
Method I — "Break" flange of coupling at each header
location. Separate flange or coupling connection to facili-
tate coil draining.
Method II — Open both valves to auxiliary drain piping.
3. After coil is drained, Method I, connect line with a ser-
vice valve and union from upper nozzle to an antifreeze
reservoir. Connect a self-priming reversible pump be-
tween the low header connection and the reservoir. Meth-
od II, make connection to auxiliary drain valves.
4. Fill reservoir with any inhibited antifreeze acceptable to
code and underwriter authority.
5. Open service valve and circulate solution for 15 minutes;
then check its strength.
6. If solution is too weak, add more antifreeze until desired
strength is reached, then circulate solution through coil
for 15 minutes or until concentration is satisfactory.
7. Remove upper line from reservoir to reversible pump.
Drain coil to reservoir and then close service valve.
8. Break union and remove reservoir and its lines.
9. Leave coil flanges or coupling open and auxiliary drain
valves open until spring.
AIR-DRYING METHOD OF COIL PROTECTION
(Unit and coil must be level for this method.)
1. Close coil water supply and return main valves.
2. Drain coil as described in procedures for Antifreeze
Methods of Coil Protection, preceding.
3. Connect air supply or air blower to inlet header connec-
tion and close its drain connection.
4. Circulate air and check for air-dryness by holding mirror
in front of open vent in outlet header drain connection.
Mirror will fog if water is still present.
5. Allow coil to stand for a few minutes; repeat Step 4 until
coil is dry.
Coil Removal
NOTE: To reinstall coils, refer to Coil Installation section on
page 131.
REMOVAL OF SINGLE HEIGHT COILS (SIZES 03-36)
The coils in horizontal coil sections must be removed from either
side of the unit. Once the external panels are removed from the
unit, the horizontal upper coil section frame members are easily
removable from the framework to allow hoisting the coil up and
out of the unit.
NOTE: Refer to Table 20 on page 66, (Dry Coil Weights)
before attempting to remove a coil from the unit.
217
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